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Ionizer

3-3

SRS Residual Gas Analyzer

Ionizer

Positive ions are produced in the ionizer by bombarding residual gas molecules with
electrons derived from a heated filament. The ions are then directed toward the entrance
of the ion filter where they are separated based on their mass-to-charge ratio.

Description

The SRS RGA ionizer is of an open design (wire mesh construction) with cylindrical
symmetry and mounted co-axially with the filter assembly. The open configuration
provides unrestricted communication between the vacuum environment and the ionizing
region. The entire assembly is built out of type 304 stainless steel for complete vacuum
compatibility. The simple mesh design is very clean (low outgassing) and easy to service.

The principle parts of the ionizer are: the repeller, the anode grid, the filament and the
focus plate.

Focus Plate

Anode Grid

Filament

Repeller

Figure 3 Ionizer Components

The filament is made out of oxidation-resistant thoria coated iridium wire, which operates
at low temperature and can be exposed to atmosphere without the risk of burn-out. The
circular construction consisting of two ThO

2

/Ir wires surrounding the anode grid

preserves the cylindrical symmetry of the ionizer. Both filaments operate simultaneously
under normal operation, and service is not interrupted if a single filament burns out (i.e.
the emission regulator automatically readjusts the temperature of the remaining filament
to restore the electron emission current). Once they wear out, the filaments can easily be
replaced in the field (Please see the RGA Maintenance chapter for details). A firmware
driven filament-protection feature constantly monitors (675 Hz) for overpressure. If
overpressure is detected the filament is immediately shut off, preserving its life.

Principle of operation

The principle of operation of the ionizer is similar to the Bayard-Alpert gauge, except
there is no central wire collector, and the electron repeller has been added.

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Содержание RGA100

Страница 1: ...8 May 2009 Operating Manual and Programming Reference Models RGA100 RGA200 and RGA300 Residual Gas Analyzer 1290 D Reamwood Ave Sunnyvale CA 94089 408 744 9040 408 744 9049 fax info thinkSRS com www t...

Страница 2: ...orized representative before returning this product for repair All users returning an RGA Probe back to the factory for repair and or service must submit a correctly completed Declaration of Contamina...

Страница 3: ...ive ground The exposed metal parts of the instrument are connected to the outlet ground to protect against electrical shock Always use an outlet which has a properly connected protective ground Servic...

Страница 4: ...SRS Residual Gas Analyzer iv...

Страница 5: ...onics Control Unit Installation 1 8 Hardware Requirements 1 8 Procedure 1 10 RGA Windows Installation 1 11 Minimum System Requirements Single Head Operation 1 11 Procedure 1 12 Turning on the RGA 1 12...

Страница 6: ...ultiplier Operation 3 14 Hardware modifications 3 18 Repeller and anode grid modifications 3 18 Repeller removal 3 19 Operation without a filament 3 19 W filament replacement 3 19 RGA Cover Nipple Rep...

Страница 7: ...he RGA System 5 5 Features and Operation 5 7 The RGA Window 5 7 Multiple Head Operation 5 7 Display Modes 5 7 Analog Mode Menu 5 7 Histogram Mode Menu 5 8 Table Mode Menu 5 8 P vs T Mode Menu 5 9 Leak...

Страница 8: ...alysis Procedure 5 20 Averaging Scan Spectrum 5 20 Pressure Reduction 5 21 Y Axis Unit Change 5 21 Head Calibration and Security 5 22 Tuning the RGA Sensitivity 5 22 Adjusting the CEM Gain 5 22 Peak T...

Страница 9: ...Programming the Quadrupole Mass Filter 6 24 Error Checking the RGA 6 25 RGA Command Set 6 29 Initialization Commands 6 30 ID 6 30 IN0 IN1 IN2 6 30 Ionizer Control Commands 6 32 DGparam param 0 20 6 32...

Страница 10: ...0 8500 0 8500 6 64 RIparam param 86 0000 86 0000 none 6 65 RSparam param 600 0000 1600 0000 none 6 67 Error Byte Definitions 6 69 Chapter 7 RGA Tuning 7 1 Introduction 7 2 Tuning Options 7 3 Peak Tun...

Страница 11: ...ntamination 8 15 Storage 8 15 CDEM Pre conditioning 8 16 CDEM Refreshment 8 17 Materials 8 17 Procedure 8 17 CDEM Replacement 8 18 Equipment 8 18 Procedure 8 18 Quadrupole filter cleaning 8 21 Equipme...

Страница 12: ...name QMSE_T3 10 9 DC Control Voltages 10 9 RF Amplitude Detection 10 10 RF Amplitude Control 10 10 Foldback Current Limiting 10 10 Schematic name QMSE_B1 10 11 Mass filter RF Supply 10 11 DC Potentia...

Страница 13: ...s to Sample High Pressure Gasses Appendix C Do I Need a PPM100 Partial Pressure Monitor for My SRS RGA Appendix D SRS RGA LabVIEW Development Kit Glossary of Terms Vacuum References RGA Parts List and...

Страница 14: ...0 CDEM User adjustable throughout high voltage range Minimum detectable partial pressure MDPP 5 10 11 Torr FC 5 10 14 Torr CDEM Operating pressure range 10 4 Torr to UHV FC 10 6 Torr to UHV CDEM Max b...

Страница 15: ...on 2 0 Probe mounting flange 2 75 CF Minimum port I D 1 375 ECU dimensions 9 1 x 4 1 x 3 1 Easily separated from the probe for bakeout LED indicators Power ON OFF Filament ON OFF Degas ON OFF Elec mul...

Страница 16: ...ltage 0 2490 STATUS Byte or query response MO Multiplier Option CDEM option NF Noise Floor 0 7 Query response Scan and Measurement Control Name Description Parameters Echo AP Analog Scan Points Query...

Страница 17: ...e RI RF_Driver 0 amu Peak Position Tuning 86 0000 86 0000 none Query response RS RF_Driver 128 amu Peak Position Tuning 600 0000 1600 0000 none Query response Error Reporting Name Description Paramete...

Страница 18: ...xviii Command List SRS Residual Gas Analyzer...

Страница 19: ...n process In This Chapter Unpacking 1 2 Before You Open the Box 1 2 Checklist 1 2 Standard Equipment Supplies 1 2 Accessories 1 2 Optional Equipment 1 2 Related Equipment 1 3 Installation 1 4 Introduc...

Страница 20: ...your unit includes the electron multiplier option Option 01 6 Do not operate the RGA if the pressure in the chamber is greater than 10 4 Torr Consult Appendix B for information on Pressure Reduction S...

Страница 21: ...nt Ionizer Kit includes filament 7 O100EM Replacement Electron Multiplier 8 O100HJR 200 qC Heater Jacket for RGA cannot be used with O100MAX 9 O100MAX Maximum Insertion nipple with 4 5 CF Flange Facto...

Страница 22: ...he vacuum chamber that provides enough clearance for the ionizer s outer cage A stainless steel tube RGA Cover Nipple covers the probe assembly with the exception of the ionizer The ionizer is the onl...

Страница 23: ...e of the vacuum chamber is greater than 10 4 Torr Consult Appendix B of this manual for details 4 The probe can be mounted directly onto any standard 2 3 4 CF port of a vacuum chamber provided the fol...

Страница 24: ...ch for standard hex head bolts and nuts or a 1 4 12 point wrench for 12 point bolt heads x Optional adapter flanges Install an adapter flange in the vacuum system if no 2 3 4 CF ports are available Ze...

Страница 25: ...r from its walls If available use the vacuum system s total pressure gauge to leak test the probe s connection and monitor the chamber s pressure as a function of time Important x Redo the metal seal...

Страница 26: ...ructions on operating without a repeller cage Electronics Control Unit Installation The Electronics Control Unit ECU attaches directly to the probe s feedthru flange Its correct alignment to the probe...

Страница 27: ...to make a power cord compatible with the RGA s power connector RGA units with the optional built in power module Option 02 are connected directly to a wall outlet using the three wire power cord prov...

Страница 28: ...f the ECU box 3 Push the locking screws of the ECU box as far as they will go into the box 4 Orient the ECU so that the two small alignment holes 1 4 diameter on its front panel and the alignment rods...

Страница 29: ...RS 232 connection Use the straight through RS232 cable with 9 pin type D connectors to connect the computer usually DTE to the RGA If your computer does not have an RS232 port use a USB to RS232 or Et...

Страница 30: ...party USB to Serial or Ethernet to serial adapter to the computer and install all necessary software drivers as indicated by its manufacturer before attempting to run the RGA Windows software Turning...

Страница 31: ...RGA installation program or select the program directly from the Window s task bar 3 Connect to the RGA Head x Click on the toolbar s RS232 Setup button or select Connector List Setup from the Head me...

Страница 32: ...isplay by default The scan range defaults to 1 to 50 amu x Select Start from the Scan menu or simply click on the toolbar s GO button to trigger an analog scan x After a small delay the analog scan da...

Страница 33: ...S RGA In This Chapter What is an RGA 2 2 The SRS RGA 2 3 Basic Operating Modes of the SRS RGA 2 5 The SRS RGA as a Mass spectrometer 2 5 The SRS RGA as a Single Gas monitor 2 6 The SRS RGA as a Total...

Страница 34: ...ions that can be connected directly to a vacuum system and whose function is to analyze the gases inside the vacuum chamber The principle of operation is the same for all RGA instruments A small fract...

Страница 35: ...er It is described in detail in the RGA Electronics Control Unit chapter of this manual It includes several regulated power supplies a microprocessor control firmware and a standard RS232 communicatio...

Страница 36: ...the need for any computer programming however the instrument can also be programmed directly using the RGA Command Set supported by its serial interface Consult the RGA Programming chapter of this man...

Страница 37: ...molecules are so small it is convenient to define a special type of mass units to express the masses of individual ions The atomic mass unit amu defined as 1 12 of the mass of a single carbon atom is...

Страница 38: ...sed to generate data for leak testing measurements and to track changes in the concentrations of several different components of a mixture as a function of time The outputs provided by a set of single...

Страница 39: ...idual gas changes Do not rely on the RGA total pressure measurement for critical applications where accurate total pressure measurements are required A high precision IGC100 controller connected to a...

Страница 40: ...d Error Analysis for the Physical Sciences New York McGraw Hill Chapters 8 9 How Mass Spectra are Interpreted A mass spectrum taken in a real system will almost always contain signals from a mixture o...

Страница 41: ...very vacuum system will have detectable amounts of hydrogen 2 amu water 18 amu carbon monoxide 28 amu and carbon dioxide 44 amu Become familiar with these species and their fragmentation patterns and...

Страница 42: ...the constants DMg and Sg are well known for the RGA being used Note The Analyze Utility of RGA Windows uses a multiple linear regression algorithm as mentioned above to automatically calculate the com...

Страница 43: ...Multiplier Gain Factor is used to correct the ion signals when the electron multiplier is turned on See the Sensitivity and Electron Multiplier Tuning sections of the RGA Tuning Chapter for details Th...

Страница 44: ...e Help Files for details on the automated tuning procedures built into the RGA Windows program Also see the Sensitivity and Electron Multiplier Tuning sections of the RGA Tuning Chapter for more gener...

Страница 45: ...as Analysis Basics 2 13 SRS Residual Gas Analyzer 9 8 10 9 Torr of Ar Note that equation 4 is a particular case of equation 3 and that the fragmentation factor for the principal peak of Ar is one by d...

Страница 46: ...2 14 Residual Gas Analysis Basics SRS Residual Gas Analyzer...

Страница 47: ...3 3 Parameter Settings 3 4 Quadrupole mass filter 3 7 Description 3 7 Principle of operation 3 8 Mass Range Resolution and Throughput 3 9 Zero Blast Suppression 3 11 Ion Detector 3 12 Description 3 1...

Страница 48: ...s ionizing some of the gas molecules positive ions separating the resulting ions according to their respective masses and measuring the ion currents at each mass The total probe equipment consists of...

Страница 49: ...igure 3 Ionizer Components The filament is made out of oxidation resistant thoria coated iridium wire which operates at low temperature and can be exposed to atmosphere without the risk of burn out Th...

Страница 50: ...y an increasing electron density toward the center Hence the ions once formed tend to stay within the anode grid structure and the ion distribution is more localized along the axis The ions formed wit...

Страница 51: ...affects the magnitude of the ion signals collected i e sensitivity of the spectrometer and limits the ultimate resolution of the mass filter Newly formed ions are attracted by the negative potential...

Страница 52: ...is prompted by the LED s If a current of 0 mA is requested the filament s heater is shut down the repeller and focus plate are biased to ground the CDEM is turned off if necessary and the Filament LE...

Страница 53: ...forated screws Figure 5 Quadrupole Mass Filter Components Round electrodes are a common replacement for hyperbolic ones in modern RGA s and result in reduced cost and ease of construction The stainles...

Страница 54: ...C values such that only the ions of interest have stable trajectories down the quadrupole rod assembly By simultaneously varying the amplitude of the DC and RF voltages an entire mass spectrum can be...

Страница 55: ...e alternating component if its magnitude and amplitude are such as to correct the trajectory whenever its amplitude tends to increase Thus the Y direction is a low pass mass filter Only low masses wil...

Страница 56: ...ular mass M and the resolution M10 at that mass Dimensionless ratio It is common practice in modern RGA s to keep M10 constant at a value which insures adequate separation of masses that are 1 amu apa...

Страница 57: ...xact relationship between resolution and sensitivity is very complex as it depends on the concentration and divergence of the ion beam leaving the source It is complicated further by the defocusing ac...

Страница 58: ...box and efficiently shields the small ion currents The FC is attached to the center feedthru with a push on connector and can easily be pulled out for cleaning or modification Notice that an electron...

Страница 59: ...detectable partial pressures as low as 5 10 11 Torr are possible with the FC However in real time applications FC detectors are rarely used to measure partial pressures below 10 9 Torr At pressures be...

Страница 60: ...need to do any sign flipping on the currents received when the CDEM is activated The gain of the electron multiplier in the RGA is a function of the bias voltage and is measured relative to the FC si...

Страница 61: ...es This mass discrimination effect is caused by the dependence of ion electron conversion efficiencies on the velocities of the ions entering the detector For example an inverse relationship with the...

Страница 62: ...discarding a multiplier Channel electron multipliers have a history of high performance and dependability in mass spectrometry applications However in order to achieve maximum useful lifetime and opt...

Страница 63: ...ed to apply the RGA probe to alternative measurement schemes involve the modification of the ionizer from its standard design The ionizer is of a very simple design and can be completely disassembled...

Страница 64: ...s back into the anode grid multiple pass configuration A decrease in ionization efficiency will usually be noticed when the repeller is removed Operation without a filament It is possible to use the q...

Страница 65: ...Cover Nipple consists of two non rotatable 2 75 CF Flanges connected by a short section of 1 5 OD tube 0 065 wall thickness The entire part is made out of stainless steel type 304 and its overall len...

Страница 66: ......

Страница 67: ...oduction 4 2 Front Panel 4 3 Rear Panel 4 4 24VDC 2 5A Connector 4 4 RS232 DCE 28 8k Connector 4 5 LED s 4 5 Locking Knobs 4 5 Power entry module Option 02 4 5 LED Functionality 4 6 STATUS Green LED s...

Страница 68: ...RGA regulated power supplies built into the ECU set the electron emission current the voltage levels on the ionizer electrodes and the high voltage across the electron multiplier RF DC levels for each...

Страница 69: ...es Figure 2 ECU Front Panel The front panel of the ECU box has nine holes of three different sizes and two locking screws The big hole in the center provides access to internal connectors that line up...

Страница 70: ...ltage 90 264 VAC Input Frequency 47 63 Hz Input voltage is set automatically Use a line voltage and frequency within ranges at right Chassis Ground Locking knob LEDs Cooling fan RS232 connector Power...

Страница 71: ...p bits LED s Eight LED s provide constant feedback on the operation of the RGA The function of the LED s is described later in this chapter Locking Knobs Use the two knobs to lock the ECU box in place...

Страница 72: ...the voltage output of the internal switching power supply If the check fails the red Error LED is turned on instead to indicate the problem Note A check on the external power supply can be performed a...

Страница 73: ...implified by an assortment of diagnostic commands built into the firmware and fully supported by the RGA Windows program Leak The Leak LED is automatically turned on whenever the filament heater is un...

Страница 74: ...converter to digitize the output of the electrometer The bandwidth and detection limit of the logarithmic electrometer are fully programmable This programmability is achieved biasing the electrometer...

Страница 75: ...ction of time Adjusting the Zero of the Ion Detector The zero of the ion detector is automatically readjusted at the beginning of each analog and histogram scan so that the baseline is always centered...

Страница 76: ...primarily capacitive so to reduce the circuit drive requirements the rod reactance is resonated with an inductance The advantages of this resonant drive circuit is the primary reason for operation at...

Страница 77: ...e any serviceable parts and does not require any routine maintenance x Do not perform any unauthorized service adjustment or modification of the instrument x Do not install any substitute parts x Cont...

Страница 78: ...4 12 Mass Filter Power supply SRS Residual Gas Analyzer...

Страница 79: ...iles 5 3 RGA files rga 5 3 RGA Scan log files ana hst tbl 5 3 RGA ASCII Data files txt 5 4 RGA Graph Metafiles wmf 5 4 System Requirements 5 4 Getting Started 5 5 Starting the RGA Software 5 5 Connect...

Страница 80: ...e Data Cursors 5 18 Cursor command 5 18 Cursor Properties command 5 18 Scheduled Saving of Data 5 18 Logging Scans 5 18 Viewing Scans 5 18 Browsing Through the Gas Library 5 19 Analyzing the Mass Spec...

Страница 81: ...or Once an RGA window is connected to a Head you can start scanning acquiring data in any of the display modes available When you are done scanning you can either close the file which will automatical...

Страница 82: ...raphs can be easily saved by RGA and then recalled by any of these programs for documentation and presentations System Requirements The RGA program system requirements vary depending on the performanc...

Страница 83: ...of RGA while it is already running the existing copy is activated and brought to the front of the screen Connecting to a Head Connecting to an SRS RGA Head requires an available RS232 port on your PC...

Страница 84: ...t button the STOP sign button 2 Turn off the filament by deselecting the Filament On command in the Head menu or click the shortcut button the filament figure button 3 Save the RGA file you have been...

Страница 85: ...you know is attached to an RGA Head to that window The operation of the RGA program is unchanged whether you have one or several heads connected and scanning The only difference you might see is a slo...

Страница 86: ...from the start to the stop mass running 7 measurements per AMU After performing a peak lock on each 7 points it then sends the maximum value to the RGA program This results in one point per mass bein...

Страница 87: ...Scan Parameters command from the Scan menu or the shortcut button of the Parameter P vs T entries can be configured independently from each other Some entries can use the Channel Electron Multiplier C...

Страница 88: ...the RGA head for that specific mass only The frequency of data acquisition is set in the Schedule setup The time to acquire each partial pressure depends on the scan speed selected the plotting speed...

Страница 89: ...ass range may be changed using either the Scan Parameters command in the Scan menu or the shortcut button of the Parameter button Data Acquisition The terms Data Acquisition and Scanning are used inte...

Страница 90: ...g scanning Almost every graph object in every display mode may be edited by double clicking on it The extent of the editing depends on the actual object For example you may change the text color font...

Страница 91: ...s Spectrum Analysis Mass spectrum analysis takes you one step beyond visual analysis and Library lookup tables RGA looks at the spectrum from 1 to 50 amu and uses a matrix inversion technique to analy...

Страница 92: ...dated when a connection is established To change the scan parameters do the following 1 Select the desired display mode from the Mode menu or by clicking one of the mode buttons 2 Select Scan paramete...

Страница 93: ...ng scans If a selected trigger period is smaller than the actual period of the scan RGA will change the trigger period to the minimum value To change the scan schedule for a mode do the following 1 Co...

Страница 94: ...d data on the screen of the previous mode When the previous display mode is called back the last scan data will be shown Running in Split Display Mode Running in split display mode allows you to view...

Страница 95: ...de the scan must be allowed to finish at the Stop mass before the data can be used as background Use the Stop at End command if in continuous scan mode to guarantee this condition To Enable the Backgr...

Страница 96: ...log file share the same parameters To log scans to disk do the following 1 Establish a connection between the RGA program and Head 2 Select a display mode that supports scan logging except the annuci...

Страница 97: ...file Library Display mode only 1 Activate the Library mode by selecting the Library command from the Mode menu 2 Use the Next Item and Previous Item in the View menu to plot the next and previous gas...

Страница 98: ...Utilities menu or click the analysis button in the Tool Bar to activate the analysis function 3 To bring up the Spectrum Analysis dialog box select the Analyze Window command from the Utilities You ma...

Страница 99: ...tion factor before they are displayed IMPORTANT Entering the wrong pressure reduction factor will result in erroneous measurements being displayed Y Axis Unit Change The default unit of the Y Axis in...

Страница 100: ...ed on your vacuum system There are two sensitivity factors one for total pressure and one for partial pressure Both factors are stored in non volatile memory in the RGA Head To tune the sensitivity fa...

Страница 101: ...mode The span is set to 10 amu with the two peak tuning gas masses set in the middle of each span If you press Scan and you have sufficient gas amounts of each peak tuning gas you should see the two...

Страница 102: ...Head Use this feature in an environment where you would like to restrict access to the head parameters When the RGA Head is locked you cannot perform certain parameter editing procedures such as Peak...

Страница 103: ...command and enter any keyword to display that topic Help Index Displays a comprehensive index to information contained in the RGA Help system To see the entries for a topic click the first letter of...

Страница 104: ......

Страница 105: ...ples of command formats 6 7 Programming tips 6 8 Communication Errors 6 9 Command errors 6 9 Parameter errors 6 9 Jumper Protection violation 6 9 Troubleshooting the RGA communications 6 11 Programmin...

Страница 106: ...param 0 255 6 45 MFparam param 1 M_MAX 6 47 MIparam param 1 M_MAX 6 47 MRparam param 0 M_MAX 6 48 SAparam param 10 25 6 50 SC param param 0 255 6 51 TP TP0 TP1 6 52 Parameter Storage Commands 6 55 MG...

Страница 107: ...Programming the RGA Head 6 3 SRS Residual Gas Analyzer Error Byte Definitions 6 69...

Страница 108: ...imple Windows Terminal program that allows you to communicate with the RGA Head directly by typing valid RGA commands on your keyboard The program functions like any common terminal program where the...

Страница 109: ...he Model number Serial number and firmware version of the RGA Unit you are connected to Important x If you make typing error the RGA s Error LED will blink Press Enter and retype the command the Backs...

Страница 110: ...ectors to connect the computer usually DTE to the ECU The DB9 to DB25 adapter provided with the unit will be needed if the computer has a 25 pin Type D connector Important If you use your own RS232 ca...

Страница 111: ...ion mark must be strictly followed by a CR terminator With a few exceptions the data returned by most query commands is a string of ASCII characters terminated by a linefeed LF decimal ASCII value 10...

Страница 112: ...ighly recommended that the host computer wait for the response of a query before a new command especially a new query is transmitted to the RGA This simplifies the communications and also eliminates b...

Страница 113: ...ote that the LED is not flashed for this error only exception to the rule Parameter errors Bad Parameter error Many different possibilities lead to a bad parameter error x The number parameter is out...

Страница 114: ...zer jumper setting provides very solid protection against inadvertently tampering with important calibration parameters stored in the RGA s memory Please refer to the RGA Command Set list to find out...

Страница 115: ...tected queering the contents of the STATUS byte in the RGA head The query command ER returns the value of the STATUS Byte for analysis and a communication error is present if Bit 0 of STATUS is found...

Страница 116: ...2 interface The ID String stored in the RGA Head is returned to the computer and the integrity of the RS232 link is assured once the character string is received The ID string also contains useful inf...

Страница 117: ...lectron Energy 70 eV Echoes the STATUS Byte IE1 Ion Energy high 12eV Echoes the STATUS Byte VF100 Focus Voltage 100V Echoes the STATUS Byte FL1 0 Filament emission 1 mA and turn filament on Echoes the...

Страница 118: ...2 so that the computer does not need to do any sign flipping on the currents received when the CDEM is activated The accuracy of the ion current measurements is insured by an internal calibration proc...

Страница 119: ...etector settings The correction factor will then be used by all measurements i e single mass and total pressure under this same detector settings to correct against zero drifts Use the HV0 command to...

Страница 120: ...re triggered with the SC command The scan parameter can be set for single multiple and continuous scanning operation The mass range for the scan is set in advance with the commands MI Initial Mass and...

Страница 121: ...re generated and transmitted Analog Scan Programming Tips x It is good programming practice to follow each command that sets a parameter with a query of the parameter setting For example the first com...

Страница 122: ...ration The mass range for the scan is set in advance with the commands MI Initial Mass and MF Final Mass A current value is transmitted for each integer mass value between MI and MF for a total of MF...

Страница 123: ...ar the RGA s transmit buffer Remember to also clear the computer s receive buffer to reset the communications The new command responsible for stopping the scan will be executed x It is good practice t...

Страница 124: ...During a Single Mass Measurement the RGA performs a Miniscan around the mass requested and the maximum current value measured is sent out over RS232 The scanning procedure referred to as Peak Locking...

Страница 125: ...e measuring Single Mass Measurement programming tips x Single mass measurements are very commonly used in program loops where several different masses are monitored in a merry go round fashion and the...

Страница 126: ...re enabled after the CDEM is turned on by using the TP1 command see Tips below The total ion current measured by the electrometer is transmitted in the standard format Integer in units of 10 16 A 4 By...

Страница 127: ...procedure Storing information in the RGA Head In order to make the RGA a stand alone mass spectrometer four parameter storage commands can be used to store head specific information in the instrument...

Страница 128: ...e RGA as a mass filter The QMF is parked at the mass requested but no actual measurements take place The command s parameter can be a real number and the step resolution is 1 256 amu The command execu...

Страница 129: ...is turned on to protect the delicate filament and CDEM from accidental overpressures Several commands can be used to trigger hardware tests on the ECU Any one of the internal checks just described ca...

Страница 130: ...ecks automatically performed upon a power on reset c Error bytes that store the results of the tests for each type of internal check d The Error Reporting command that queries the error byte The Error...

Страница 131: ...nds The ER command used to monitor the STATUS byte regularly returns a non zero byte value Further analysis shows that bit 1 is set indicating a filament problem The EF command is then used to read in...

Страница 132: ...ED s while programming the RGA Diagnose problems as soon as they are detected x Even though a lot of internal checks are performed by the microprocessor not all possible internal error conditions are...

Страница 133: ...sequence specifies the command name The rest of the sequence consists of parameters Three types of parameters are allowed numbers asterisk default param and question mark query Not all commands accep...

Страница 134: ...ady to go x Check the quality of the RS232 connection to the host computer x Check the user s communication software to make sure it is communicating properly with the RGA x Check the serial numbers o...

Страница 135: ...ometer and the QMF RF P S is performed and the necessary error bytes are updated IN1 Reset the RGA to its factory default settings In addititon to the above the RGA is reprogrammed to its default i e...

Страница 136: ...rge flux of highly energetic electrons degasses the ionizer in a process known as electron stimulated desorption Degassing is done in a very controlled fashion The electron emission current is ramped...

Страница 137: ...ued for the Degas command to react to it Some more time a few seconds must be provided to let the pre degas electron emission current be reestablished at the end Parameters DG0 Do nothing command Comm...

Страница 138: ...er setting is returned over RS232 in ASCII format Error checking Number parameters must be within the accepted range and must be integers The absence of a parameter i e EE is treated as a parameter er...

Страница 139: ...quested electron current is achieved FL The command is excecuted using the default parameter value Default 1 00 mA FL Returns over RS232 the value of Electron Emission Current in mA actually flowing t...

Страница 140: ...alue of the anode grid parameter is returned over RS232 in ASCII format Note that it is the parameter value and not the actual voltage level that is returned Error checking Number parameters can be 0...

Страница 141: ...tivated Command excecution times vary depending on the pre existing ionizer conditions The end of the command excecution is prompted to the host computer sending out the STATUS byte over RS232 Paramet...

Страница 142: ...lly cleared after a complete recalibration CL of the electrometer is performed and also when the unit is turned off x Use the CA command every time the detector settings are changed to values that hav...

Страница 143: ...A Error Checking An attempt to pass any parameter with CA results in a bad parameter error being reported CL Description Calibrate Electrometer s I V response Echo STATUS error byte Perform a complete...

Страница 144: ...utomatically reconfigures the electrometer to measure negative currents when a finite biasing voltage is selected The current measurement algorithm is also automatically reconfigured so that the magni...

Страница 145: ...the magnitude of the positive currents measured x The HV_LED is turned off x The STATUS Byte is sent out to prompt the end of the command HVparam param 10 2490 The parameter is the magnitude of the C...

Страница 146: ...provided standard with a Faraday Cup detector For increased sensitivity and faster scan rates an optional CDEM is offered The MO command can be used to determine whether Electron Multiplier detection...

Страница 147: ...ommand See the CA command for details and more recommendations RGA Windows note When using the RGA Windows program to operate the RGA the Scan Speed parameter setting available in the Scan Parameter S...

Страница 148: ...nts an ion current and as such corresponds to 4 bytes being received by the host computer The AP query is used to verify that the RGA and the host computer agree on the number of bytes that will be ex...

Страница 149: ...ram Scans under the present scan conditions The scan parameter can be set for single multiple and continuous scanning operation A Histogram Scan consists of as a succession of individual mass measurem...

Страница 150: ...used for multiple scan excecution Default parameter value 1 single scan Error checking Number parameters must be within the specified range and be integers No query format is allowed Programming Tips...

Страница 151: ...and Histogram scans The last ion current transmitted during an Analog or Histogram scan corresponds the mass to charge ratio specified by the MF parameter Important Note that the final mass setting i...

Страница 152: ...ess than or equal to the final mass setting MF or else a parameter conflict communications error is generated The absence of a param i e MI generates a bad parameter error MRparam param 0 M_MAX Descri...

Страница 153: ...ram scan or using the CA command under the same detector settings An offset correction factor is calculated and stored in memory that it is then automatically used by the Miniscan procedure to correct...

Страница 154: ...of analog scan The parameter specifies the number of steps per amu During an analog scan the quadrupole mass filter is stepped at fixed mass increments through the mass range specified by the MI and...

Страница 155: ...ry command The ion currents are represented as integers in units of 0 1 fA and transmitted directly in Hex format four byte integers with 2 s complement format and Least significant byte first The typ...

Страница 156: ...ll the data is transmitted out to the host computer over RS232 As a result of the high acquisition rate of the RGA there might be a delay between the time at which the data is collected and the time a...

Страница 157: ...o 1 amu and the DC bias is zeroed All ionic species have stable trajectories down the filter under those conditions and reach the ion current detector with different efficiencies x TP_Flag is cleared...

Страница 158: ...tal Pressure query A total pressure measurement is triggered and a total ion current value is returned over RS232 The actual response to the command depends on the status of TP_Flag as described above...

Страница 159: ...rameter interpreted as a CDEM gain in units of thousands is stored in the non volatile memory of the head MG Electron Multiplier Gain parameter query Error checking The absence of a parameter i e MG i...

Страница 160: ...it is simply stored in memory so it can be read and used by any host computer connected to the instrument See HV command Partial Pressure Sensitivity factors are gas specific probe specific and highl...

Страница 161: ...ly dependent on the ionizer conditions and on aging of the probe Note The parameter loaded at the factory is the total pressure sensitivity factor for N2 under default ionizer conditions Parameters ST...

Страница 162: ...ler against temperature fluctuations The result is very stable RF DC levels that are highly insensitive to the operating conditions of the RGA Head Important The RF DC stabilization algorithm Step 2 a...

Страница 163: ...ED Description DET_ERR Byte Query Echo DET_ERR Byte Query the value of DET_ERR and update its value after running a fresh check on the Electrometer Bit5 of STATUS and the DET_ERR byte are updated bas...

Страница 164: ...r detatils on the different error bytes of the RGA Consult the RGA Troubleshooting chapter of this manual for possible causes and solutions to any problems reported Parameters This command is a query...

Страница 165: ...chapter of this manual for possible causes and solutions to any problems reported Always try the query a second time before declaring a hardware problem Parameters This command is a query and can only...

Страница 166: ...its of the STATUS byte are found set the specific error bytes PS_ERR DET_ERR QMF_ERR CEM_ERR FIL_ERR and RS232_ERR must be queried individually to diagnose the problem Consult the Error Byte Definitio...

Страница 167: ...ce of a parameter i e EC is treated as a bad parameter error DIparam param 0 255 Description DI Parameter adjust Peak Width Tuning command JP100 Jumper protected Echo Query Response Program the value...

Страница 168: ...Command the value of DI in non volatile memory is updated and the internal scan parameters used to program the DC during scans and single mass measurements are updated accordingly DI Use this format t...

Страница 169: ...measurements Note to Supervisors A calibration disable jumper JP100 available on the circuit board can be used by a supervisor to block any attempt to modify the value of the DI parameter Supervisors...

Страница 170: ...olatile memory of the RGA Head and used by the firmware to generate the internal scan parameters used to step the RF during scans and single mass measurements Note to Supervisors A calibration disable...

Страница 171: ...he purpose of a Peak Position Tuning Procedure is to determine the voltages that the RF Driver must output at 0 and 128 amu so that all the peaks in an analog spectrum appear in the right position The...

Страница 172: ...is often used to compensate against small temperature drifts in the mass scale caused by drifts in the output of the RF_Driver Error checking The absence of a parameter i e RS is treated as an error i...

Страница 173: ...ifferent problems based on their Error Codes and suggests possible causes and solutions Bit Internal Check a ERROR Byte c Query d 7 not used N A N A 6 24V External P S b PS_ERR EP 5 Electrometer b DET...

Страница 174: ...Used 0 Not Used PS_ERR Error Byte 24V P S Error Byte Bit Description Error Code 7 ADC16 Test failure DET7 6 DETECT fails to read 5nA input current DET6 5 DETECT fails to read 5 nA input current DET5...

Страница 175: ...Not used 4 Power supply in current limited mode RF4 3 Not Used 2 Not Used 1 Not Used 0 Not Used QMF_ERR Error Byte Quadrupole Mass Filter RF P S Error Byte Bit Description Error Code 7 No Electron Mul...

Страница 176: ...ssure too high FL5 4 Not used 3 Not used 2 Not used 1 Not used 0 Single filament operation FL0 FIL_ERR Error Byte Filament Error Byte Bit Description 7 Not used 6 Parameter conflict 5 Jumper protectio...

Страница 177: ...r should be performed by qualified personnel only A mistuned RGA Head could give Erroneous Readings until it is retuned properly In This Chapter Introduction 7 2 Tuning Options 7 3 Peak Tuning Procedu...

Страница 178: ...ions of this chapter describe several tuning procedures designed to assure that all the calibration conditions described above are satisfied prior to a set of partial pressure measurements All tuning...

Страница 179: ...ptions Peak Tuning Peak Tuning Peak Position Peak Width Sensitivity Tuning Sensitivity Tuning Partial Pressure Total Pressure Electron Multiplier Tuning Channel Electron Multiplier Gain adjustment a H...

Страница 180: ...ur Peak Tuning requires a mixture of gases whose mass spectra is well known In general a two gas mixture one with low mass peaks and one with high mass peaks is sufficient The sample is introduced int...

Страница 181: ...st the low end of the mass axis a high mass gas with a mass to charge ratio close to the upper limit of the instrument s mass range is used to adjust the high end of the mass scale Several analog scan...

Страница 182: ...of the RGA Command Set and the instructions of the following two sections Peak Position Tuning Algorithms The magnitude of the RF determines the mass to charge ratio of the ions that can pass through...

Страница 183: ...mass peak by a distance m amu in the mass axis the value of RI must be modified from its original value RI0 according to RI RI0 m RS 128 Notes x The new RI value must fall within the acceptable param...

Страница 184: ...are saved in the non volatile memory of the RGA Head DI and DS commands respectively and used by the firmware to generate the internal scan parameters used to adjust DC_Tweek during scans and single m...

Страница 185: ...repeat the two width adjustments one or two more times until both low and high mass peaks show the desired widths Note Changes in the peak positions will also be observed at a rate of 0 40 amu per amu...

Страница 186: ...the RF power supply to its controlling voltages might be affected or more fundamentally the relationship between mass and RF levels in the filter might change for example if the QMF changes its physic...

Страница 187: ...ors must be obtained under the same operating conditions that will be used during general partial pressure analysis since they depend on many instrumental parameters including ionization energy emissi...

Страница 188: ...measurements replaced by total pressure measurements The total pressure sensitivity factor in units of mA Torr can be saved into the non volatile memory of the RGA Head using the ST command The param...

Страница 189: ...n Factor stored in the non volatile memory of the RGA Head is used by the RGA Windows program to correct the ion signals when the electron multiplier is turned on i e all data acquired while the elect...

Страница 190: ...o of the multiplier output current to the Faraday cup output current Note that there is no need to change the sign of the electron multiplier signal prior to the division since the firmware automatica...

Страница 191: ...e 8 6 Ionizer Degas 8 7 Ionizer Replacement 8 8 Equipment 8 8 Procedure 8 8 Filament Replacement 8 11 Handling and care of the filament 8 11 Equipment 8 11 Procedure 8 11 CDEM Handling and Care 8 14 H...

Страница 192: ...8 2 SRS Residual Gas Analyzer Equipment 8 18 Procedure 8 18 Quadrupole filter cleaning 8 21 Equipment 8 21 Procedure 8 22 SRS Probe Refurbishing Service 8 25...

Страница 193: ...use the product if it has unauthorized modifications Return the product to SRS for service and repair to ensure that safety features are maintained x Use only SRS supplied replacement parts x Disconn...

Страница 194: ...ems does not guarantee that the cleaning procedures described in this chapter will completely remove contamination from the probe In some cases i e depending on the vacuum composition replacement of t...

Страница 195: ...lter components The performance of the spectrometer is affected by the build up of electrostatic charge on the contaminated surfaces The symptoms of the problem are decreased sensitivity decreased res...

Страница 196: ...m the probe 3 Wrap a heating tape or heating jacket around the entire probe and cover with fiberglass insulation if necessary Make sure the entire probe including flanges is evenly covered 4 Bake the...

Страница 197: ...electrons The complete process takes three minutes and can be triggered directly from the RGA Windows software Head Menu The emission current is ramped slowly during the first minute to eliminate sudd...

Страница 198: ...head x Needle nose pliers x Latex gloves powder free x Clean dust free work area Procedure 1 Read all warnings at the beginning of this chapter before attempting to service the probe 2 Set up in adva...

Страница 199: ...not be moved during this procedure 11 Finally remove the two screws that hold the focus plate against the top alumina spacer and pull out the plate The short alignment rod will also need to be removed...

Страница 200: ...visually the entire ionizer assembly to assure the correct alignment of its parts and if satisfied mount the probe back on the vacuum system Check the correct rotational orientation of the feedtrhu fl...

Страница 201: ...Filament Replacement kit consisting of new filament and spare screws and nuts x One standard OFHC copper gasket for 2 3 4 CF Flange New and Clean x Precision flat head screw driver 2 5 mm head x Need...

Страница 202: ...t and become acquainted with the way in which it is mounted on the filament rods The SRS RGA filament is of a circular shape and made out of very thin thoria coated iridium wire Two platinum tabs spot...

Страница 203: ...s correct shape if needed Note use a clean cotton swab for this procedure 16 Attach the repeller to the longer filament rod using a fresh screw Align the cage and tighten the screw Correct alignment i...

Страница 204: ...n 100qC Bakeout temperature The bakeout temperature must be less than 300qC with no voltage applied across the unit Operating voltage The maximum voltage applied to any CDEM should never exceed 3500V...

Страница 205: ...traps with diffusion pumps particularly for slicone oil based pumps and molecular sieves traps with mechanical roughing pumps whenever possible If the multiplier becomes contaminated it must be clean...

Страница 206: ...initial operation to trace peaks with gradual increase in abundance levels over the first two hours of operation of a new CDEM All CDEM s undergo an initial cleanup phase during which absorbed gases a...

Страница 207: ...higher than 100qC setting Warning The fumes from isopropyl alcohol can be dangerous to health if inhaled and are highly flammable Work in well ventilated areas and away from flames Warning Read and fo...

Страница 208: ...ulate matter Wear talc free rubber gloves or finger cots Use properly degreased tools Avoid excessive shock such as from dropping onto a hard surface Remember that the CDEM is made out of glass Use on...

Страница 209: ...ent following the procedures described earlier in this chapter Inspect the CDEM for signs of arcing and contamination A blue tinge is an indication of an electrical arc while brown indicates contamina...

Страница 210: ...inspect the assembly and do any adjustments that might be necessary The CDEM should be standing straight up centered between its two neighboring rods and with its cone facing straight into the FC shie...

Страница 211: ...in order to clean the rods the entire quadrupole head assembly must be taken apart and unless the exact nature of the deposits is known the only sure way to remove them will be with a very fine abrasi...

Страница 212: ...ction of the unit Check for loose damaged misaligned and severely contaminated components If excessive contamination is evident take the necessary steps to identify and eliminate the contamination sou...

Страница 213: ...tilled water to remove the cleaning solvent Following the rinses blow dry the rods with filtered dry nitrogen and then bake them out in an oven at 180qC for fifteen minutes Warning After the parts hav...

Страница 214: ...lips in all the grooves located above the alignment holes of the bottom alumina spacer The clips hold the filter tightly against the exit plate Finally install the filament and the repeller cage 11 Vi...

Страница 215: ...maintenance steps can choose to send the RGA unit back to the factory for a complete Probe Refurbishing Service Please contact SRS to obtain information on this very fast and convenient service All r...

Страница 216: ...8 26 Quadrupole filter cleaning SRS Residual Gas Analyzer...

Страница 217: ...oubleshooting procedures for the SRS RGA In This Chapter Warnings 9 2 Internal Error Detection in the SRS RGA 9 3 Basic Troubleshooting 9 5 Built in Hardware Checks 9 10 24V DC Power Supply 9 10 Elect...

Страница 218: ...supplied replacement parts x Disconnect the ECU box from the probe before servicing any of the probe components x Turn off the emission and wait for at least 30 minutes before removing a probe from a...

Страница 219: ...ilament problems and are turned on in addition to the Error LED whenever the ionizer s emission is internally shut down or not established as requested 2 Error Queries Querying the Error Bytes with th...

Страница 220: ...reporting slate Please see the Error Reporting Commands list for details x Communications errors are different from hardware errors in that the Error LED only flashes two or three times when the prob...

Страница 221: ...cause erroneous ion current readings Troubleshooting Contact SRS Error Code DET3 Type of Error Electrometer Error Message Electrometer Error COMPENSATE fails to read 5nA input current Error Cause The...

Страница 222: ...his unit Upgrade the RGA to an Electron Multiplier option Option 01 Error Code FL6 Type of Error Filament Background Protection Mode Error Message Filament Error Unable to set the requested emission c...

Страница 223: ...ment still does not turn on contact SRS Error Code FL7 Type of Error Filament Background Protection Mode Error Message Filament Error No filament detected Error Cause No filament was detected after an...

Страница 224: ...rror Message RF P S Error Primary Current exceeds 2 0 Amps Error Cause The circuit that drives the primary of the RF Transformer is delivering an unusually large current Troubleshooting Check for a sh...

Страница 225: ...large mass range If the problem is still present warm up the unit further by performing one or more Degas cycles or setting the quadrupole mass filter to t50 amu for 15 minutes see Programming the Qu...

Страница 226: ...heck see Error Reporting Commands x The prefix of the Error Codes associated to the check x Is this a Power on check 24V DC Power Supply STATUS Bit affected 6 Error Byte affected PS_ERR Error Reportin...

Страница 227: ...of input current If an error is detected Bit 5 of STATUS is set DET_ERR is updated and the Error LED is turned on The detector is reconfigured to its pre check configuration once the tests are over Qu...

Страница 228: ...tions detected during Background Filament Protection are x Filament not present burnt or not installed x Unable to set the requested emission current If any of these two error conditions is detected w...

Страница 229: ...rviceable parts inside x Dangerous voltages capable of causing injury or death are present in this instrument Use extreme caution whenever the ECU covers are removed Do not remove the covers while the...

Страница 230: ...10 10 Foldback Current Limiting 10 10 Schematic name QMSE_B1 10 11 Mass filter RF Supply 10 11 DC Potentials 10 12 Schematic name QMSE_B2 10 12 Filament Heater Supply 10 12 Bias Regulators 10 13 Schem...

Страница 231: ...an electron multiplier The ECU box 3 x 4 x9 contains all the electronics necessary to operate the RGA It connects directly to the probe s feedthru flange and also to a host computer Its regulated pow...

Страница 232: ...U is a DC potential amplitude and V0 is an RF potential amplitude The physics of the quadrupole mass filter show that the resolution of the instrument improves with the frequency Z Sf the ions interac...

Страница 233: ...onverter connects to the top PCB A second small vertical PCB holds the electron multiplier s HV supply A third small vertical PCB is used to pass signals and power between the two main PCBs The bottom...

Страница 234: ...into 18 bit RF control D A converter PA4 CS_DAC8 Strobe low to assert CS to octal 8 bit DAC PA5 LD_LEDS Strobe high to load LED data into output register PA6 LD_MPX Strobe high to load multiplexer da...

Страница 235: ...s input multiplexer Q4 MPX_1 Middle bit of 16 bit A D converter s input multiplexer Q5 MPX_2 MSB of 16 bit A D converter s input multiplexer Q6 EMIT_CTL Filament heater duty cycle control 0 direct 1...

Страница 236: ...and bias in order to assure accurate readings over its 8 decade range A programmable voltage source U209 and associated components can provide voltages from microvolts to volts which are applied to t...

Страница 237: ...zero until set by the microcontroller The triple 2 1 analog switch U301 a 74HC4053 is used to make certain that various circuits remain off when the system is reset until the CPU can establish the sy...

Страница 238: ...From here empirical adjustments to RES_CTL vs amu may be made to optimize the instrument s performance but to first order RES_CTL will be a constant Factory cal only with DS 0 RF Amplitude Control The...

Страница 239: ...al fashion the two windings are placed side by side so that the magnetic flux seen by the two windings is very nearly identical Measurements on these transformers show a difference in self inductance...

Страница 240: ...the primary drive current is at 86 4 kHz The switcher s transformer has a 6 1 turns ratio reducing the 24V input to a 4V output which leaves about 3 5V after rectification in the dual Schottky diode D...

Страница 241: ...ors R538 and R539 directly into the emitter of Q506 and away from the emitter of Q505 which are biased at ground These currents are mirrored by Q503 504 and Q507 508 to the output node which has a 1M...

Страница 242: ...secondary has a pair of half wave doublers C635 C636 and D615 D618 to provide r250V The third secondary has a full wave rectifier D619 D622 to provide 20VDC which is filtered by C622 C623 and L603 All...

Страница 243: ...ncreases with bias current increasing the noise Back to back diodes are used to allow either ion currents Faraday cup case or electron currents electron multiplier case to be measured During calibrati...

Страница 244: ...mary current in the HV inverter is sensed by R814 a 2 2 resistor If the primary drive exceeds 230 mA the output of the difference amplifier U800B will go positive reducing down the primary drive level...

Страница 245: ...yzer Chapter 11 RGA Probe Assembly This chapter contains two RGA probe assembly drawings In This Chapter RGA Probe Assembly Schematic 11 3 Feedthru Flange Connectors Schematic 11 4 O100MAX Maximum Ins...

Страница 246: ...11 2 SRS Residual Gas Analyzer...

Страница 247: ......

Страница 248: ......

Страница 249: ...is assumption fails in two ways First it is simply not true a total pressure measurement cannot tell the user tell the user the level of impurities As an example a system operating at a total pressure...

Страница 250: ...RGA with an electron multiplier detector 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 13 1 0x10 12 1 0x10 11 1 0x10 10 1 0x10 9 1 0x10 8 1 0x10 7 1 0x10 m z Torr Ultimate Vac...

Страница 251: ...lium 105 explains why the peak is only three decades smaller The ability to detect these common species and many others is the essence of the RGA The fragmentation of molecules in the ionizer of the R...

Страница 252: ...x10 9 7 2x10 9 8 4x10 9 9 6x10 8 1 1x10 8 1 2x10 Atomic Mass Units Torr Vacuum Diagnosis Figure 2a Pump Oil Contamination 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 0 6 1 0x10 6 2...

Страница 253: ...removing this contamination We have observed that organic solvents such as acetone and 1 1 1 trichloroethane TCE are more tenacious contaminants than the oil they are designed to remove Figure 3 show...

Страница 254: ...stem does not quickly reach its ultimate vacuum the next step is commonly a high temperature bakeout If the vacuum system has still not reached its ultimate vacuum problems are suspected and typically...

Страница 255: ...entered into the RGA software by the user During measurements the RGA measures only each peak Because the whole spectrum is not measured data is acquired much faster The two examples that follow show...

Страница 256: ...pump A small load lock is attached to the chamber which can be rough pumped by the same mechanical pump and purged with nitrogen At 0 30 the isolation valve between the turbo pump exit and mechanical...

Страница 257: ...aximum operating pressure is 10 4 mbar the dynamic range of the RGA is 6 decades or 1 ppm The noise floor of the channel electron multiplier CEM is lower but its maximum operating pressure also decrea...

Страница 258: ...for only the smallest leaks Having a built in leak detector makes working with vacuum systems much easier and faster and the SRS RGA is far less expensive than a standard helium leak detector The proc...

Страница 259: ...1 u 10 8 scc sec 1 which is measured with a FC detector To measure smaller leaks a CEM detector can be used or the turbo pump can be throttled to decrease the pumping speed Supply Gas Valve Seats Lea...

Страница 260: ...llow valves can be difficult to leak test due to the large volume of gas contained between the bellow and the valve body To perform a quick leak test it is required to change the composition of the ga...

Страница 261: ...n a vacuum system can be noticed and acted on before they become serious problems Hard to correlate cause effect relations are much easier to establish with the wealth of statistical data that can be...

Страница 262: ...sign of pressure reduction systems for RGA s Vacuum Process Sampling 10 to 10 5 mbar Figure 1 shows a schematic of a basic pressure reduction system The system has two paths to the RGA a high conducta...

Страница 263: ...erating pressure for a Faraday cup detector it is about 10 10 mbar Therefore the dynamic range of the measurement varies from 5 decades at high process pressure to only 3 decades at the low pressures...

Страница 264: ...ing such that the effective pumping speed at the RGA ionizer is as high as possible Figure 2 shows two layouts that both have the same signal level The layout with the RGA at the end of a small tube h...

Страница 265: ...stant tc volume flowrate If the aperture had a small dead volume of 1 2 inch of 0 250 OD tube 0 028 wall the time constant would be 35 seconds This is not an acceptable response time 10 mbar 10 mbar 6...

Страница 266: ...mpler designed with the above considerations The sub second response and cleanup are almost as fast as the RGA can acquire data Sample Valve Aperature Inlet Hybrid Turbo Pump Diaphragm Pump Bypass Val...

Страница 267: ...ve and some tube The configuration seen in Figure 4 is made possible by the recent advances in hybrid turbomolecular drag pumps and diaphragm pumps Traditional designs would have relied on a two rotar...

Страница 268: ...Appendix B SRS Residual Gas Analyzer 7...

Страница 269: ...4 What does the PPM100 controller do 5 Partial Pressure Monitor and Control 5 Leak Test Analysis 5 Mass Spec Display 6 RGA Control 7 Analog I O Ports 7 Capacitance Manometer readings CM1 4 8 Data Logg...

Страница 270: ...ical applications need access to RGA data over the world wide web operate in process environments incompatible with PCs require uninterrupted 24 7 access to partial pressure data require a compact and...

Страница 271: ...to any SRS RGA100 200 300 residual gas analyzer can continuously monitor and display partial pressures of up to eight individual gas components It includes a touchscreen LCD front panel display press...

Страница 272: ...ntroller Warning PPM100 is not compatible with third party residual gas analyzers A menu driven user interface allows the PPM100 operator to easily program all required RGA Setup parameters from the c...

Страница 273: ...l pressure readings and alarm status for up to eight individual gas species Leak Test Analysis The PPM100 can be used to leak test components attached to the vacuum system Use leak trend graphs to det...

Страница 274: ...ode is available to graph RGA Mass Spectra directly on the front panel of the controller During analog scanning the quadrupole mass spectrometer is stepped at fixed mass increments i e 0 1 amu through...

Страница 275: ...Press the E MULTIPLIER button at any time to activate the electron multiplier detector during analog scans All RGA ionizer settings are easily configured from the touchscreen LCD user interface Figur...

Страница 276: ...oller can display pressure as measured by standard capacitance manometers CMs Up to four independent CM readings can be monitored simultaneously Pressure readings are updated at 2 Hz The PPM100 precis...

Страница 277: ...tools such as 1 cursor 2 zoom 3 x y axis scaling manual and auto and 4 cursor readings Users can switch rapidly between current and logged readings for the pressures or analog signals of interest The...

Страница 278: ...verride is available for all process control channels making it possible to manually control channel relays and TTL output levels directly from the front panel Manual relay control makes it possible t...

Страница 279: ...er to an external computer to access its full performance and functionality All instrument functions and parameters are manually accessible and easily modified through its menu driven user interface I...

Страница 280: ...sure versus time tables etc The EWS can also be configured to allow access to process control functions so that any vacuum system can be monitored and controlled from anywhere in the world Tip Use the...

Страница 281: ...e of the simplest and most reliable ways to build process control and interlocking capabilities into a vacuum system setup Use the 8 channels of process control to make mission critical decisions base...

Страница 282: ...o large and laptops are generally considered too delicate for the process floor The standalone PPM100 solves all of the above problems with a small rugged reliable and rack mountable package i RGA use...

Страница 283: ...wish to deal with computers software upgrades and system crashes There is a modern trend to dedicate a PC to every new instrument or sensor in the lab However PCs cannot generally be regarded as frien...

Страница 284: ...k data storage RGA Windows is still sometimes required to perform RGA tuning operations such as 1 mass axis calibration 2 sensitivity calibration and 3 E MULT gain adjustment However RGA users must ke...

Страница 285: ...nge 12 Vdc Resolution 14 bit In 12 bit Out Update rate 2 Hz Connector BNC Gauges Total Pressure Capacitance Manometer Number of gauges Simultaneous readout of up to four capacitance manometers using t...

Страница 286: ...ttp www ni com for training and support of LabVIEW x This appendix assumes familiarity with the LabVIEW programming environment It also assumes familiarity with the implementation of Virtual Instrumen...

Страница 287: ...i The kit was developed in part to accommodate users who asked for more features in our RGA Windows software While many users asked for similar features each had their own special requirements beyond...

Страница 288: ...stalled to use the application on a system without LabVIEW These software components are included in the download and will automatically be installed with the SRS RGA LabVIEW application Browsing the...

Страница 289: ...t including inputs and outputs for each VI To print documentation under LabVIEW 5 1 go to File Print Documentation Under LabVIEW 6i go to Print In both cases follow the prompts to print the level of d...

Страница 290: ...lopment Kit goes far beyond this primitive layer Most users should work at the operations layer first only using the communications layer when strictly necessary An oversimplified example CommExamplec...

Страница 291: ...rogram supplied with your RGA to verify communications are set up correctly Make sure the power to the RGA is on check the power LED verify the COM port setting is correct and test the cabling Concept...

Страница 292: ...g point numbers Unless there is an error or the user changes the status of the scan enable button on the front panel these commands repeat in the while loop until an entire scan is generated After a s...

Страница 293: ...table analog and histogram It is likely that your custom application can be created simply modifying one of these examples Simple Table Try the example Open LabVIEW Select the RGA LabVIEW Library Open...

Страница 294: ...e traces do not appear after thirty seconds or you get an error use the RGA COM program supplied with your RGA to verify communications are set up correctly Make sure the power to the RGA is on check...

Страница 295: ...l handle that for you After taking your input from the specifications cluster and opening an SRS RGA session the Start Table VI sets the electron emission and calibrates any noise floor electron multi...

Страница 296: ...he trace does not appear after thirty seconds or you get an error use the RGA COM program supplied with your RGA to verify communications are set up correctly Make sure the power to the RGA is on chec...

Страница 297: ...is is different from the previous example of Simple Table scanning where the points are simply plotted as they are read in In Simple Analog and Histogram the initialized array changes in the ordinate...

Страница 298: ...VI takes a few moments before the scan begins in order to perform some initialization tasks on the RGA After this time you should see histogram bars corresponding to the partial pressures detected by...

Страница 299: ...l you don t have to worry about dealing with the VISA session directly the VIs in this layer will handle that for you In this VI an array of all the points in the scan is created beforehand and each p...

Страница 300: ...VIEW as compared with RGA Windows is that there is no detector calibration utility However if you are like most users calibration of the detector is only rarely required and you can always go back to...

Страница 301: ...from the RGA Ionizer Setup Dialog Click the button labeled Ionizer Setup This dialog allows you to change parameters relating to the ionizer hardware Your parameter values may differ from the figure...

Страница 302: ...can do a manual calibration of your electron multiplier by following these steps Raise the high voltage setting of the EM Set the Gain factor to 1 Run an analog scan in both faraday cup and EM detect...

Страница 303: ...will let you scan with the filament off Scanning Logging Setup Dialog Click the button labeled Scan Log Setup The Scanning Logging dialog allows you to set up a scan for any of the three scanning mode...

Страница 304: ...clicking in the box labeled CEM To set the log filename simply click on Select log file and follow the prompts to select the directory and filename you wish to use Click on the toggle button next to t...

Страница 305: ...20 Appendix D SRS Residual Gas Analyzer Click the button labeled Start Scanning After a few moments you should get a window that looks something like the next figure...

Страница 306: ...and linear representations of the ordinate scale When you are finished with the demo stop the scan by pressing the button labeled STOP Examine the log file by opening the file in your favorite text ed...

Страница 307: ...checkboxes for Enable Web Server and Log File Unless you have reason to use other values simply use the default values for the root directory and the log filename Error information will be stored in...

Страница 308: ...ver will update this picture repeatedly to give the appearance of a movie of your running VI At the time of writing only Netscape browsers support this kind of automatic updating Bear in mind that if...

Страница 309: ...bring up the above URL within a browser on the computer running the VI but not other computers Note the filename you used In this case it is analog htm In order to access the HTML page with the embedd...

Страница 310: ...Appendix D SRS Residual Gas Analyzer 25 Select TCP IP and click the Properties button to find the IP address...

Страница 311: ...hing feature of LabVIEW 6i Run SRSRGAa Main vi and run the analog scan or whichever scan mode you used the web publishing tool with Go to another computer on your network and type the IP address of th...

Страница 312: ...Appendix D SRS Residual Gas Analyzer 27...

Страница 313: ...28 Appendix D SRS Residual Gas Analyzer...

Страница 314: ...spectrometer Atomic mass unit abbreviation amu A unit of mass equal to one twelfth the mass of a neutral carbon atom having six protons and six neutrons 12 C equivalent to 1 660566 10 27 kg Background...

Страница 315: ...elative to ground and is resistively heated to incandescence with an electrical current from the emission regulator The thermionically emitted electrons are accelerated towards the anode grid which is...

Страница 316: ...1 cm through a gas at unit pressure typically 1 mTorr It depends on the ionization potential of the electrons used for bombardment Ionizer Probe Component The portion of the mass psectrometer probe th...

Страница 317: ...as being measured Noise Random fluctuation in the output signal unrelated to a change in the partial pressure of the gas from which the signal is derived The appropriate measure of noise is the standa...

Страница 318: ...at that mass Dimensionless ratio RGA Abbreviation for Residual Gas Analyzer RGA Cover Nipple CF Nipple that covers the RGA Probe Scan Speed mass spectrometer The speed at which the RGA scans through...

Страница 319: ...free elctrons or ions Space charge can causes serious changes in the potential distributions of the ionizer and ultimately limits the pressure operating range of all RGA s Total Pressure The average n...

Страница 320: ...SUREMENTS WITH RESIDUAL GAS ANALYZERS 9 MULTIPLE LINEAR REGRESSION ANALYSIS ALGORITHMS 10 VACUUM SYSTEM DESIGN 10 VACUUM SYSTEM CONTAMINATION 15 VACUUM PUMPS 18 TOTAL PRESSURE MEASUREMENT 22 BAYARD AL...

Страница 321: ...ides one of the best introductions to vacuum technology and vacuum system design we have ever seen 7 Walter H Kohl Handbook of Materials and Techniques for Vacuum Devices American Vacuum Society Class...

Страница 322: ...RGA was retrofitted with a Spindt type field emitter array Residual gas spectra indicate reduced O Cl and F electron stimulated desorption 12 Shue Watanabe Hitoshi Oyama Shigeki Kato and Masakazu Aon...

Страница 323: ...RGA required Phil Danielson joins this long standing debate 26 Vladimir I Baranov Analytical Approach for Description of Ion Motion in QMS J Am Soc Mass Spectrom 14 2003 818 27 Vladimir I Baranov Anal...

Страница 324: ...national September 1990 12 P Ausloos et al The Critical Evaluation of a Comprehensive Mass Spectral Library J Am Soc Mass Spec 10 1999 287 299 13 Robert Waits Semiconductor and thin film applications...

Страница 325: ...on the effects of contaminants on sputter deposited films 25 Russ Carr Sensor Automates Detection of Photoresist Residues R D Magazine March 2000 p 51 26 Robert Waits Evolution of integrated circuit v...

Страница 326: ...ance potential mass spectrometry Discrimination of Dissociative ionization products J Vac Sci Technol A18 2 2000 299 5 Babu Chalamala Robert Wallace and Bruce Gnade Poisoning of Spindt type molybdenum...

Страница 327: ...s for Permanent Gas Analysis J Am Soc Mass Spec 13 2002 1004 Note The SRS RGA100 is compared to several commercial i e Leybold XPR 2 and Ferran Micropole and research mass specs and found to be the be...

Страница 328: ...997 p 125 2 Haripov F J Vac Sci Technol A 15 4 1997 2434 Rarefied gas flow through a long tube at arbitrary pressure and temperature drops 3 Batey J H Vacuum 44 5 7 1993 639 Fractionation in gas inlet...

Страница 329: ...Mass Spec 13 2002 1004 Note The SRS RGA100 is compared to several commercial i e Leybold XPR 2 and Ferran Micropole and research mass specs and found to be the best match for the analysis of cryogenic...

Страница 330: ...l Sealed Components Are Not Just for UHV Anymore R D Magazine October 1997 p 24 9 Glen Tisdale et al Solid State Technology May 1998 Next Generation Aluminum Vacuum Systems 10 P R McCabe et al J Vac S...

Страница 331: ...995 2738 26 S Kurokouchi Influence of lubricating conditions of fixing bolts on penetration of Conflat flange knife edge into gasket J Vac Sci Technol A18 1 2000 288 27 W F Smith B G Stokes and J F Cr...

Страница 332: ...2000 p 55 41 Vic Comello Viewport Shutter Designs Meet Deposition Requirements R D Mag June 2000 p 87 42 C Biscardi et al Application of Porcelain Enamel as an UHV compatible electrical insulator JVS...

Страница 333: ...gy July 2001 p 153 58 M Mapes Summary of Quick Disconnect vacuum flanges J Vac Sci Technol A19 4 2001 1693 59 Phil Danielson Molecular Flux Provides Process Understanding R D Mag August 2001 p 65 60 P...

Страница 334: ...ify the task Gases and technology July August 2004 p 43 75 Phil Danielson Sealing Materials Require a Careful Choice R D Magazine August 2004 p 29 76 Donald M Mattox Safety Aspects of Vacuum Processin...

Страница 335: ...229 9 Fumio Watanabe and Maki Suemitsu Separation of ESD neutrals from outgassing originating from the grid surface of emission controlled gauges Studies with a heated grid gage J Vac Sci Technol A 1...

Страница 336: ...ave Laube Limitations of CO2 cleaning for Semiconductor Process Tools A2C2 Magazine February 2001 p 9 for general info on this article email info a2c2 com 26 Phil Danielson Contamination Lurks in Vacu...

Страница 337: ...e October 1996 p 41 Turbodrag Pumps Offer Improved Throughput and Light Gas Compression 5 Baliga J Semiconductor International October 1997 p 86 Vacuum Pump Designs Adjust to Harsher Conditions 6 Vic...

Страница 338: ...signed for Harsh Environments R D Magazine March 2000 p 45 22 Phillip A Lessard Vacuum Pumping Systems for Chemical Vapor Deposition Tools Vacuum Technology Coating June 2000 p 34 23 J J Manura Vacuum...

Страница 339: ...aphragm Pump Designs Determine Results R D Magazine November 2000 38 Phil Danielson How to Match Pumping Speed to Gas Load R D Magazine December 2000 p 30 39 Phil Danielson Careful Consideration Means...

Страница 340: ...38 53 Donald Mattox Turbomolecular Vacuum Pumps Vacuum Technology and Coating Jan 2003 p 24 54 Ron Hawranko How to Choose a TurboPump R D Magazine July 2003 p 46 55 Phil Danielson Matching Cryopumping...

Страница 341: ...n May 1996 p 54 9 John Sullivan Advances in Vacuum Measurement Almost Mette Past Projections R D Magazine August 1995 p 31 10 Peter Singer Trends in Vacuum Gauging Semiconductor International March 19...

Страница 342: ...nization Gauges J Vac Sci Technol A19 4 2001 1712 3 Gerardo Brucker Which Bayard Alpert Gauge is best for you R D Magazine Feb 2000 p 69 4 Peter Nash The use of hot filament ionization gauges Vacuum 3...

Страница 343: ...tions on gauge operation 19 R N Peacock and N T Peacock Sensitivity variation of Bayard Alpert Gauges with and without closed grids from 10 4 to 1 Pa J Vac Sci Technol A 8 1990 3341 20 Bills D G JVST...

Страница 344: ...ations at ionization gauges Vacuum Vol 47 1996 No 4 351 355 36 Edelmann Chr Kauert R Kieler O F O On some Improvements of Ionization Gauges of the extractor Type for the Measurement of Extreme High Va...

Страница 345: ...basic and important stuff you need to know Move on to dig deeper 2 J English et al J Sci Instrum 42 1965 77 A wide Range constant resistance Pirani Gauge with ambient temperature compensation 3 Heijne...

Страница 346: ...10 J Setina Two Point calibration scheme for the linearization of the spinning rotor gauge at transition regime pressures J Vac Sci Technol A 17 4 1999 2086 11 Sharrill Dittmann et al The Molecular dr...

Страница 347: ...he Solid Lattice 6 J L Gland et al Surface Science 355 1996 L385 The effects of exposure time and pressure on the TPD spectra of systems with bulk states 7 A M de Jong et al Thermal Desorption Analysi...

Страница 348: ...M J Weiss C J Hagedorn and W H Weinberg Observation of gas phase atomic oxygen with Ru 001 p 1x1 D at 80K J Vac Sci Technol A 16 6 1998 3521 Note an SRS RGA200 is used to collect the TPD data 21 Babu...

Страница 349: ...n JVST A19 2001 673 Note a pinched tube valve compatible with H Voltage operation is described Vacuum and Process Control Publications 1 The Journal of Vacuum Science Technology A Vacuum Surfaces and...

Страница 350: ...in the U K e mail tech techpub org 10 AVS Monograph Series The American Vacuum Society AVS www vacuum org publishes a whole series of monographs on vacuum technology and processing subjects They are...

Страница 351: ...__________________________________________ _______________________________________________________________________ _______________________________________________________________________ 1 Was any of...

Страница 352: ...tal Film 50V 5 40 85c C 207 5 00052 512 01U Cap Stacked Metal Film 50V 5 40 85c C 208 5 00052 512 01U Cap Stacked Metal Film 50V 5 40 85c C 209 5 00285 562 100P Cap NPO Monolitic Ceramic 50v 5 Ra C 21...

Страница 353: ...92 407 49 9K Resistor Metal Film 1 8W 1 50PPM R 101 4 00138 407 10 0K Resistor Metal Film 1 8W 1 50PPM R 102 4 00887 407 133K Resistor Metal Film 1 8W 1 50PPM R 103 4 00138 407 10 0K Resistor Metal Fi...

Страница 354: ...m R 229 4 00192 407 49 9K Resistor Metal Film 1 8W 1 50PPM R 230 4 00192 407 49 9K Resistor Metal Film 1 8W 1 50PPM R 231 4 00555 407 590 Resistor Metal Film 1 8W 1 50PPM R 232 4 00130 407 1 00K Resis...

Страница 355: ...297 Integrated Circuit Thru hole Pkg U 305 3 00632 340 AD810 Integrated Circuit Thru hole Pkg U 306 3 00382 340 OPA37 Integrated Circuit Thru hole Pkg U 307 3 00633 340 MAX528CPP Integrated Circuit Th...

Страница 356: ...0157 533 1U Capacitor Metallized Polyester C 622 5 00100 517 2 2U Capacitor Tantalum 35V 20 Rad C 623 5 00100 517 2 2U Capacitor Tantalum 35V 20 Rad C 624 5 00100 517 2 2U Capacitor Tantalum 35V 20 Ra...

Страница 357: ...Q 400 3 00022 325 2N3906 Transistor TO 92 Package Q 404 3 00627 325 MPSA92 Transistor TO 92 Package Q 405 3 00628 325 MPSA42 Transistor TO 92 Package Q 406 3 00627 325 MPSA92 Transistor TO 92 Package...

Страница 358: ...Carbon Film 1 4W 5 R 441 4 00188 407 4 99K Resistor Metal Film 1 8W 1 50PPM R 442 4 00079 401 4 7K Resistor Carbon Film 1 4W 5 R 443 4 00079 401 4 7K Resistor Carbon Film 1 4W 5 R 444 4 00081 401 470...

Страница 359: ...W 5 R 550 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 551 4 00083 401 47K Resistor Carbon Film 1 4W 5 R 615 4 00303 407 7 87K Resistor Metal Film 1 8W 1 50PPM R 616 4 00800 401 1 Resistor Carbon Fi...

Страница 360: ...00054 512 047U Cap Stacked Metal Film 50V 5 40 85c C 819 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 820 5 00052 512 01U Cap Stacked Metal Film 50V 5 40 85c D 501 3 00625 302 MBR1535CT Diode Du...

Страница 361: ...5 R 708 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 709 4 00032 401 100K Resistor Carbon Film 1 4W 5 R 800 4 00166 407 200K Resistor Metal Film 1 8W 1 50PPM R 801 4 00034 401 10K Resistor Carbon Fi...

Страница 362: ...7 00664 720 MS 37 Fabricated Part Z 0 7 00665 720 MS 38 Fabricated Part Z 0 7 00668 720 MS 41 Fabricated Part Z 0 7 00710 709 MYLAR INSULATOR Lexan Overlay Z 0 9 00396 907 3 8 RED Shrink Tubing Z 0 9...

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