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3-10    Programming the RGA ECU

SRS QMS Gas Analyzer

-Check the quality of the serial connection to the host computer.
-Check the user’s communication software to make sure it is communicating properly with
the RGA.
-Check the serial numbers of the RGA ECU’s connected to the computer's serial ports.

Programming the Ionizer

Positive ions are produced in the ionizer by bombarding residual gas molecules with electrons derived
from a heated filament.  The operational parameters that affect the efficiency of the ionizer are: electron
energy, ion energy, electron emission current, and focusing voltage. The 

Ionizer Control

 Commands

program all the ionizer voltages, turn the filament on/off, and Degas the ionizer. The STATUS byte is
transmitted at the end of their execution.

Important

:  Remember that the repeller grid and the focus plate are only biased while the filament is

emitting electrons.

Setting the ionizer parameters

The following list of commands will set the electron energy to 70 eV, ion energy to high (12eV), focus
voltage to -100V and it will then turn the filament on with an emission current setting of 1.0 mA. It is a
typical example of the set of commands sent to the RGA while programming the ionizer.

EE70 Electron 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 STATUS  Byte.

Ionizer Programming Tips

•

 

It is possible to trigger scans and single mass measurements if the filament is not turned on.

•

 

Make sure the pressure is under 10

-4

 Torr before turning the filament on or degassing.

•

 

Whenever possible replace a Degas procedure with a thorough Probe Bakeout (See RGA
Maintenance Chapter for details). Keep the degas time to the minimum value that will get
the job done. Frequent degassing compromises the lifetime of the filament.

•

 

The filament is frequently tested by the CPU while it is turned on. Consult the Filament,
Leak and Burnt LED’s after activation for immediate status feedback.

•

 

Wait for the STATUS byte to be returned between commands and check it every time for
possible errors.

•

 

In cases were a hardware error is reported retry the command one more time before
declaring a hardware problem.

•

 

Default parameter settings are available for all the Ionizer Control commands

•

 

Use the FL0 command to turn off the filament.

Содержание QMS 100 Series

Страница 1: ...ual QMS 100 Series Gas Analyzer 1290 D Reamwood Avenue Sunnyvale CA 94089 U S A Phone 408 744 9040 Fax 408 744 9049 Email info thinkSRS com www thinkSRS com Copyright 2012 All Rights Reserved Version...

Страница 2: ...from the supplier Contact Stanford Research Systems or an authorized representative before returning this product for repair Trademarks Ultra Torr and VCR are registered trademarks of Swagelok Co Tygo...

Страница 3: ...Inside 1 4 Operation 1 7 Mass Spectrometry Basics 1 16 Chapter 2 Windows Software 2 1 Overview 2 3 System Requirements 2 4 Getting Started 2 4 Features and Operation 2 6 RGA Head and Scan Parameters...

Страница 4: ...e Voltage The QMS system is specified for line power of either 110 V 60 Hz or 220 V 50 Hz The diaphragm pump will only operate on the specified voltage Operating at other voltages will damage the moto...

Страница 5: ...v SRS QMS Gas Analyzer...

Страница 6: ...GO button on the tool bar and a scan will begin from 1 to 50 amu The mass spectrum will show a rough background spectrum Click the filament button on the toolbar to deactivate the ionizer Loosen the i...

Страница 7: ...lectron multiplier optional Range 1 to 200 atomic mass units amu Resolution 0 5 amu at 10 of peak height Detection limit 10 ppm with Faraday cup detector 1 ppm with electron multiplier Operating press...

Страница 8: ...lumina ceramic seals Viton buna N and nitrile butyl rubber misc aluminum Tygon General Startup time 2 minutes from full stop Max Ambient Operating Temperature 35 C Power requirement either 110 V 60 Hz...

Страница 9: ...our system with the specific corrosive environment The QMS system contains the following materials Body 304 stainless steel high vacuum tube 316 stainless steel quarter inch tube and fittings molybden...

Страница 10: ...actory calibration of the inlet and capillary The factor is entered in the pressure reduction factor dialog box under the Utilities menu in the RGA software Although the RGA software will store the va...

Страница 11: ...s Sample Mode 1 10 Startup Just the Pumps 1 10 Startup the Sample Flow 1 10 Idle 1 11 Shutdown 1 11 Batch Analyze Mode 1 12 Microcontroller Error Checks 1 13 Operating Modes of the Spectrometer 1 14 T...

Страница 12: ...e spectrum can be acquired in under one minute and individual masses can be measured at rates up to 25 ms per point This modern system allows many new applications where the traditional mass spectrome...

Страница 13: ...intain a quality seal The o ring can be inspected for damage by completely removing the nut and ferrule The standard capillary shipped with each instrument consists of a 0 005 inch bore PEEK capillary...

Страница 14: ...ntain no oil or other liquids and therefore gravity has no effect on them If the system is to be laid on its side the left side viewed from front should be down If the handle and rubber feet are remov...

Страница 15: ...k valves These valves use precision knife edges to create microscopic gaps Such an inlet would draw gas at only 5 l per minute from atmospheric pressure into the RGA chamber This flowrate is so small...

Страница 16: ...ents are made The ionizer converts the sample gas into an ionized gas that is collected by electric fields into the filter The quadrupole mass filter contains a precisely controlled high frequency ele...

Страница 17: ...on the front panel and the one main power switch The main power switch activates the cooling fan and provides power to the system When the main power is on the RGA is active and can be communicated w...

Страница 18: ...an example the controller waits for the turbo pump to reach full speed before opening the sample valve The controller sets the light adjacent to each switch to indicate the status of each component BL...

Страница 19: ...ss Flow Sample Flow 2 1 T urbo pum p is not at speed P res s ure is high E rror co nditions which caus e a retreat to previous s tate 2 5 B atch Analyze 2 1 2 2A Test Bypass 2B Turbo Pum p Figure 1 6...

Страница 20: ...ill perform the sequence following the state diagram through state 2A When these actions are complete the system will be sampling and ready to record data This is the main mode of operation Other acti...

Страница 21: ...slowly The less exposure to water the quicker the background will be lowered For long periods idle the system by closing both valves With the capillary flow closed the work load of the diaphragm pump...

Страница 22: ...is an special mode designed for advanced users and requires constructing a custom inlet apparatus You can ignore this section and mode unless you specifically require the batch feature This mode requ...

Страница 23: ...flow will not be started until the turbo pump is at speed If the pressure at the inlet to the QMS is above 5 mbar the microcontroller opens the capillary flow in short pulses The valve is pulsed repea...

Страница 24: ...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 isotope 12 i e 1...

Страница 25: ...le mass measurements are often used in process control programs to control alarms analog and digital outputs and relays RGA Windows uses this mode to generate its data for the Table Pressure vs time A...

Страница 26: ...re of various gases Careful and complete interpretation of the spectrum i e a complete spectral analysis should reveal the identity as well as the concentrations of the various components which have p...

Страница 27: ...s partial pressures This section describes the basic steps needed to perform quantitative measurements with the instrument The formalism presented assumes multiple gas analysis but is equally valid fo...

Страница 28: ...tion patterns included in the RGA Library of RGA Windows can be used as a source of Mg values in moderately quantitative determinations However when very precise numbers are desired one should obtain...

Страница 29: ...uning chapter of this manual for more details on this calibration procedure A total pressure sensitivity factor is also needed by the RGA to convert the ion currents obtained during total pressure mea...

Страница 30: ...standards the partial pressure sensitivity factor stored at the factory corresponds to N2 measured at 28 amu with m10 1 amu default ionizer settings and Faraday Cup Detection Single gas measurement e...

Страница 31: ...pter Overview 2 3 Program Structure 2 3 RGA Files 2 3 RGA files rga 2 3 RGA Scan log files ana hst tbl 2 3 RGA ASCII Data files txt 2 4 RGA Graph Metafiles wmf 2 4 System Requirements 2 4 Getting Star...

Страница 32: ...18 Viewing Scans 2 18 Browsing Through the Gas Library 2 19 Analyzing the Mass Spectrum 2 19 Spectrum Analysis description 2 19 Analysis Procedure 2 20 Pressure Reduction 2 20 Head Calibration and Sec...

Страница 33: ...play modes available When you are done scanning you can either close the file which will automatically disconnect you from the head or you can issue a disconnect command and keep the file open for fur...

Страница 34: ...hoose to scan at the fastest speed and want the RGA program to keep up with the head then a faster computer i o card and graphics card might be required Following is the minimum recommended system to...

Страница 35: ...232 cable to the DB9 connector on the Head labeled RS232 DCE 28 8k Baud 2 Connect the other end of the cable to the RS232 port on the PC side 3 Turn On the RGA Head 4 Start MS Windows and the RGA Prog...

Страница 36: ...ning When an RGA window is sized all the graph objects in it are also sized down or up For optimum viewing of a graph maximize the RGA program window and maximize the RGA file you wish to view Multipl...

Страница 37: ...performs a peak lock for each mass and calculates one amplitude per mass This peak is then plotted as a bar at the appropriate mass The X Axis represents the mass range chosen in the Scan Parameters m...

Страница 38: ...l pressure depends on the scan speed selected for that mass the plotting speed depends on the user s computer In Table mode split with Analog or Histogram mode the Table entry values are extracted fro...

Страница 39: ...e status of the Alarm levels The gas mass name and scan parameters may be configured from the Scan Parameters command Scan menu The Leak Trace bar meter color and text readout color can be edited by d...

Страница 40: ...a histogram or analog graph the mass range of the library will automatically match that graph s range for easy comparison of gases All library information is read from the gaslib dat ASCII file locate...

Страница 41: ...ing is enabled by default to insure no data is every lost Every scan mode has logging options They can be changed buy selecting Scan Logging in the File menu Spectrum Analysis can also be logged Graph...

Страница 42: ...ting Your RGA A Maintenance Schedule menu item lets you protect your RGA by automatically turning the filament or CEM off if the RGA is left to idle for a selected time Sensitivity Factors The RGA Hea...

Страница 43: ...fic command information please use the On Line Help for the RGA Program Note For detailed information and command description of the RGA program please refer to the RGA On Line Help files provided on...

Страница 44: ...ored in the Head and are used in subsequent operations Changing Scan Trigger Rates The scan trigger rate schedule determines the frequency with which a scan is repeated Not all display modes have the...

Страница 45: ...ented the pressure will reach the discharge region Do not leave the RGA with the CEM on when a system is being shut down Better yet do not leave the RGA on at all when the vacuum chamber is being shut...

Страница 46: ...h Histogram Table P vs T and Library Table split with Analog Histogram P vs T and Library P vs T split with Analog Histogram Table and Library You cannot split with Leak or Annunciator modes To split...

Страница 47: ...General Utilities Note For detailed information and command description of the RGA program please refer to the RGA On Line Help files provided on the program CD The RGA help system includes a detaile...

Страница 48: ...the logging by selecting the Scan Logging command from the File menu or by clicking the logging Folder button in the toolbar The logging directory must be selected for every scan mode or you can use...

Страница 49: ...2 Press the Show All button to list all available gases 3 Use the scroll bar and or the keyboard to search the list or use the Search Masses section to look for specific gases Library Display mode AND...

Страница 50: ...ze mode The list of 12 gases used in the Analyze mode can be changed interactively by the user directly from the program A user also can enable disable the logging of analysis data to the disk Pressur...

Страница 51: ...d Partial Pressure then enter the mass whose pressure you will be measuring in the Mass Selection edit box 4 Enter the pressure indicated by your pressure gauge in the Reference Pressure Reading 5 Pre...

Страница 52: ...see the effect of the change on the graph Use the graph scaling command AutoScale to scale the data The peak tuning procedure must be performed in the order described below You may repeat the entire p...

Страница 53: ...c password The password is case sensitive 3 Confirm the password exactly as entered above 4 Press Lock To Unlock the head parameters do the following 1 Select the Lock Head Parameters command form the...

Страница 54: ...Questions A Q A help files has been included with the RGA program This file includes the most commonly asked questions about the SRS RGA system Double click on the RGA Q A Help Icon to view this file...

Страница 55: ...essure 3 3 Total Pressure and Composition 3 4 Calibration of Partial Pressure 3 5 Initial Calibration 3 6 Basic Recalibration 3 7 Calibration for Multiple Operating Conditions 3 8 Calibration with Fix...

Страница 56: ...t at or under 1 amu to avoid overlap between adjacent peaks Changes in m10 during the measurements caused by aging severe contamination and large temperature changes will cause variations in the sensi...

Страница 57: ...experiment with the specific gas of interest equipment and operating conditions will yield a curve describing how the pressure at the RGA varies with Pin Operating Off the Design Pressure Each system...

Страница 58: ...determine the composition xi a value for PT must be known In many applications total pressure is constant and therefore partial pressure is proportional to mole fraction When total pressure is not co...

Страница 59: ...the intrinsic sensitivity of the RGA head the sensitivity factors of the RGA are defined for Faraday Cup detection A separate Electron Multiplier Gain Factor is used to correct the ion signals when th...

Страница 60: ...gies for using each value are discussed in the following sections starting with the basic technique that was performed at the factory Initial Calibration Initially a default value is stored in the RGA...

Страница 61: ...t in the dialog box that appears under the Utilities Pressure Reduction menu item 2 Setup the QMS to sample the reference gas 3 Choose the Head Sensitivity Tuning menu item to make the Sensitivity Tun...

Страница 62: ...open the appropriate RGA file and connect the window to the ECU if the ECU is already connected to another window disconnect from that window first The software will now be ready to make measurements...

Страница 63: ...and being inert they do not interact with the RGA probe and do not contribute to its aging Peak tuning can be easily performed with RGA Windows using the Peak Tuning command of the Head Menu The prog...

Страница 64: ...der described below 1 Low mass peak position adjustment 2 High mass peak position adjustment 3 Repeat 1 2 in that order one or two more times until no more changes in peak positions are observed 4 Low...

Страница 65: ...am its output voltages The purpose of the 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...

Страница 66: ...spacing between peaks in the spectrum An increase in RS results in the peaks getting closer together and a decrease in RS results in the peaks getting further apart from each other The effect is more...

Страница 67: ...ove the peak width tuning procedure requires the introduction of two known gases into the vacuum system A low mass gas 1 20 amu recommended is used to adjust peak widths at the low end of the mass sca...

Страница 68: ...section of the RGA Probe chapter of this manual for details on that limit Temperature Effects on the Mass Scale Calibration As the temperature of the RGA Head changes two different effects affect the...

Страница 69: ...put 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 automatically reverses its sign b...

Страница 70: ...hen the sample is measured Thereby the backstreaming component of the mass spectrum will be the same as in the sample measurement The software can only subtract two spectra when they cover the same ma...

Страница 71: ...d by a CO fragment A better choice would be to use the peak at 14 to measure nitrogen Once you have chosen a mass that is representative of each species of interest you then refer to published fragmen...

Страница 72: ...or metal plates before the inlet to provide sacrificial surfaces for condensation The sacrificial surfaces should have good thermal connections to the outer walls so that they stay at room temperature...

Страница 73: ...chamber Base pressure also Background pressure Total pressure before introduction of any gases into a vacuum system Usually the base pressure is the lowest pressure that is typically achieved in the v...

Страница 74: ...ion An ion of mass smaller than that of the original parent molecule Fragmentation or cracking pattern The fragment distribution of ionic species which results from dissociation and ionization of mul...

Страница 75: ...n the signal response is observed See linearity Linearity The extent to which the change in output signal of the RGA is proportional to the corresponding change in partial pressure Mass analyzer Probe...

Страница 76: ...in a vacuum system Partial Pressure The pressure of a designated component of a gaseous mixture within a system as it is exerted on the chamber walls The sum of the partial pressures of all the kinds...

Страница 77: ...background values Sg H H0 P P0 The units of Sg are of ion current per unit pressure amp Torr for example Total Pressure The total pressure sensitivity of the RGA to a gas g is defined similarly as the...

Страница 78: ...Jul Aug 1994 Ultrahigh vacuum in the semiconductor industry Vic Comello R D Magazine September 1993 p 65 Process Monitoring with Smart RGAs Waits et al Semiconductor International May 1994 p 79 Contro...

Страница 79: ...Technical Reference Manual QMS 100 Series Gas Analyzer Version 3 2 1 2012...

Страница 80: ...om the supplier Contact Stanford Research Systems or an authorized representative before returning this product for repair Trademarks Ultra Torr Swagelok and VCR are registered trademarks of Swagelok...

Страница 81: ...Command Syntax 3 5 Communication Errors 3 7 Programming the RGA ECU 3 9 RGA Command Set 3 25 Error Byte Definitions 3 64 Chapter 4 Trouble Shooting 4 1 System Problems 4 2 Internal Error Detection in...

Страница 82: ...ystem A standard 1 4 inch connection is provided for this purpose Ventilation The QMS system requires forced air cooling to operate at a reasonable temperature Do not block the air inlet or exhaust on...

Страница 83: ...n multiplier CDEM optional Resolution per AVS standard 2 3 Greater than 0 5 amu 10 peak height Adjustable to constant peak width throughout the entire mass range Sensitivity A Torr 2 10 4 FC 200 CDEM...

Страница 84: ...current 0 to 3 5 mA programmable System Pumps hybrid turbomolecular drag pump 70 liter s ultimate pressure 2 10 9 mbar diaphragm pump with ultimate pressure less than 1 mbar protection class IP44 Mate...

Страница 85: ...the specific corrosive environment The QMS system contains the following materials Body 304 stainless steel high vacuum tube 316 stainless steel quarter inch tube and fittings molybdenum electrical f...

Страница 86: ...0 1 STATUS Byte or query response VF Focus Plate Voltage 0 150 STATUS Byte or query response Detection Control Name Description Parameters Echo CA Calibrate All none STATUS Byte CL Calibrate Electrom...

Страница 87: ...0 Query response ST Total Pressure Sensitivity 0 0000 100 0000 Query response Mass filter control Name Description Parameters Echo ML Mass Lock 0 0000 M_MAX none Tuning Name Description Parameters Ech...

Страница 88: ...yte Query Query response EQ QMF_ERR Byte Query Query response EM CEM_ERR Byte Query Query response EF FIL_ERR Byte Query Query response EC RS232_ERR Byte Query Query response Note M_MAX 100 for RGA100...

Страница 89: ...s the sample It has no knowledge of the pressure reduction or the gas handling subsystem This chapter describes the overall instrument and the components that are responsible for delivering the sample...

Страница 90: ...e 1 Main components of the QMS are labeled 1 microcontroller 2 aperture 3 sample valve 4 pressure gauge 5 bypass valve 6 quadrupole electronics 7 mass spectrometer 8 analyzer chamber 9 24V power suppl...

Страница 91: ...e microcontroller is active as soon as the main power is on It has control of the two pumps two valves and the front panel Controller The two valves and two pumps are directly controlled by the microc...

Страница 92: ...he handle holes accept 1 4 20 bolts and the feet accept 6 32 screws Note that the inserts only support tension they will push out if large thrust loads are applied Do not permanently hang the instrume...

Страница 93: ...trying to locate a leak by moving the capillary tip around a fitting on a gas line With the capillary in the example above you could be 1 16 of an inch away from the leak source and not detect it for...

Страница 94: ...ed sccs The conductivity of various geometries is calculated with the standard formulas available in texts discussing vacuum see References The pressures and flow at every point in the system is deter...

Страница 95: ...lution of the entire set would determine all the unknowns except that there are more unknowns than equations Typically the inlet pressure is know and the desired pressure at the spectrometer is known...

Страница 96: ...The speed is 2 6 liter min 1 at 5 mbar which corresponds to 13 milliliter min 1 at 1000 mbar The turbo pump only operates with exhaust pressures up to approximately 5 mbar which limits the useful rang...

Страница 97: ...approaches 5 mbar the work it performs will increase The current monitor display on the front panel is a good indicator of the power consumed by the pump Running the pump near its limit mainly causes...

Страница 98: ...e determined equation 1 A typical design point is an exit pressure of 1 2 mbar and a corresponding flow rate of 1 5 to 3 5 milliliter min 1 see figure 4 The inlet pressure is determined by the users a...

Страница 99: ...spheric pressure and an capillary exit pressure of 1 mbar From the speed curve for the diaphragm pump the throughput Q is 2 5 10 2 mbar liter s 1 Q P S and the required conductivity is 2 5 10 5 liter...

Страница 100: ...d plastic 0 002 in smallest bore cost not flexible low temperature Three conventional methods are available for making connections to the capillaries metal compression fittings graphite seals and o ri...

Страница 101: ...destroy the response time of the instrument At 1 ml per minute it would take 33 minute for gas to travel from the inlet to the QMS The correct approach would take less than 2 seconds The decrease in p...

Страница 102: ......

Страница 103: ...ration Lockout 2 3 Electrometer 2 5 Detection limit vs scan rate 2 5 Adjusting the Zero of the Ion Detector 2 6 Mass Filter Power Supply 2 7 Ionizer 2 8 Description 2 8 Principle of operation 2 9 Para...

Страница 104: ...304 stainless steel and high purity alumina It analyzes residual gases ionizing some of the gas molecules positive ions separating the resulting ions according to their respective masses and measurin...

Страница 105: ...and converts them to voltage signals that are read by a built in A D converter The microprocessor automatically compares those signal voltages against an internal calibration and calculates the magnit...

Страница 106: ...2 4 ECU SRS QMS Gas Analyzer changes in the calibration parameters by inexperienced operators Peak tuning is completely disabled when the jumper is configured to the CAL DIS setting...

Страница 107: ...lution is achieved using a 16 bit A D converter to digitize the output of the electrometer The bandwidth and detection limit of the logarithmic electrometer are fully programmable This programmability...

Страница 108: ...perating conditions and even as a function 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...

Страница 109: ...nding DC potential is a maximum of about 430 VDC for masses of 300 amu 215 Vdc on one rod pair and 215 Vdc on the other The frequency of operation of the mass filter is the same for all models and is...

Страница 110: ...er are the repeller the anode grid the filament and the focus plate Figure 3 Ionizer Components The filament is made out of oxidation resistant thoria coated iridium wire which operates at low tempera...

Страница 111: ...es increase the ionization efficiency of the electron current relative to single pass configurations Within the anode grid volume ions are attracted to the center by the negative potential produced by...

Страница 112: ...ith the electron energy until a maximum is reached For most molecules this maximum is in the range of about 50 100 eV and for electron energies above the maximum the ionization efficiency slowly decre...

Страница 113: ...eved A Background Filament Protection Mode is automatically enabled to monitor the performance of the filament while it is emitting electrons The Filament LED remains on as long as the filament is emi...

Страница 114: ...high purity alumina insulators Figure 5 Quadrupole Mass Filter Components In modern RGA s round electrodes are a common replacement for hyperbolic ones and result in reduced cost and ease of construct...

Страница 115: ...on of DC and RF voltages control the quadrupole filter operation Successful separation of a specific mass species requires setting the RF and DC values such that only the ions of interest have stable...

Страница 116: ...her hand in the Y direction heavy ions will be unstable because of the defocusing effect of the DC component but some lighter ions will be stabilized by the alternating component if its magnitude and...

Страница 117: ...10 Ratio between a particular 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...

Страница 118: ...r to the mass being filtered The exact 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 compli...

Страница 119: ...electrometer through a coaxial feedthru which extends into the ECU box and efficiently shields the small ion currents The FC is attached to the center feedthru with a push on connector and can easily...

Страница 120: ...that value the CDEM option becomes a much better alternative allowing for faster scan rates and improved signal to noise ratios The best characteristics of FC detection are simplicity stability large...

Страница 121: ...ller than 2500 Volts The sensitivity of the spectrometer increases with the gain of the electron multiplier Higher sensitivities provide lower minimum detectable partial pressures and faster spectral...

Страница 122: ...ecific ionic species being detected An important problem when working with multipliers is that their gain changes with time Gain degradation is unavoidable and particularly serious just after the dete...

Страница 123: ...useful lifetime and optimum performance it is very important to handle them very carefully Please read the CDEM Handling and Care section in the Service chapter to familiarize yourself with some of t...

Страница 124: ......

Страница 125: ...3 9 Programming the Ionizer 3 10 Programming the Detector 3 11 Setting up Analog Scans 3 13 Setting up Histogram Scans 3 14 Single Mass Measurements 3 16 Total Pressure Measurements 3 18 Storing Infor...

Страница 126: ...00 0000 3 51 MVparam param 0 2490 3 51 SPparam param 0 0000 10 0000 3 52 STparam param 0 0000 100 0000 3 53 Mass Filter Control Commands 3 54 MLparam param 0 0000 M_MAX 3 54 Error Reporting Commands 3...

Страница 127: ...agnostic program The RS232 interface connector of the RGA is a standard 9 pin type D female connector configured as a DCE transmit on pin 3 receive on pin 2 with full RTS CTS handshaking enabled The C...

Страница 128: ...To connect to an RGA ECU do the following 1 Start the RGA Com program 2 Select the Select Com Port command from the COM port Setup menu 3 Select the Com port you want usually COM2 from the list box an...

Страница 129: ...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 and...

Страница 130: ...y 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 buffe...

Страница 131: ...d no command is executed Command too long error 14 characters are received over RS232 without a CR ever being detected The Receive buffer is flushed Bit 2 of RS232_ERR and Bit 0 of STATUS are set and...

Страница 132: ...r and the spectrometer s ECU during programming 1 Visual Clue The first clue of a communication error can be obtained watching the Error LED while communicating with the ECU The ERROR_LED is flashed o...

Страница 133: ...oes the RGA s ID string IN0 Clear communication buffers Echoes the STATUS Byte The ID command is used to test the RS232 interface The ID String stored in the RGA ECU is returned to the computer and th...

Страница 134: ...current setting of 1 0 mA It is a typical example of the set of commands sent to the RGA while programming the ionizer EE70 Electron Energy 70 eV Echoes the STATUS Byte IE1 Ion Energy high 12eV Echoe...

Страница 135: ...eived when the CDEM is activated The accuracy of the ion current measurements is insured by an internal calibration procedure that calibrates the output of the electrometer against input current over...

Страница 136: ...ecMult LED to visually inspect the status of the CDEM during programming Use the HV command to query the type of detector that is currently active The CDEM is active if a non zero response is returned...

Страница 137: ...NF and HV commands The zero of the RGA s ion detector is automatically readjusted at the beginning of each analog scan so that the baseline is centered around zero The offset correction factor calcul...

Страница 138: ...display depends on a large number of factors including the scan rate NF setting of the RGA the host computer s processing speed and the amount of handshaking activity over the RS232 lines As computers...

Страница 139: ...pecified by the last Peak Tuning procedure are programmed on the RF rods as a function of mass Important The detector s zero and the internal scan parameters are checked and corrected at the beginning...

Страница 140: ...checks its internal memory to make sure that no data from any previous scan is pending to be transmitted If data is still pending the RGA must first finish transmitting the stored data before the new...

Страница 141: ...ctron multiplier is turned off and the FC is connected to the electrometer the noise floor is set to the maximum averaging best signal to noise ratio and longest measurement time the zero of the detec...

Страница 142: ...and the detector Thus by disabling the mass discriminating action of the analyzer section it is possible to use the RGA as a total pressure ionization gauge Total pressure measurements are automatica...

Страница 143: ...etails There is no query for the TP_Flag value If the status of the flag is unknown prior to requesting a Total Pressure measurement use TP1 to set the flag or TP0 to clear it as needed TP_Flag is cle...

Страница 144: ...ctor of 0 1mA Torr the second line stores into memory a total pressure sensitivity of 0 02mA Torr and the last two lines store a 1400V 10 000 gain calibrated pair for the CDEM SP0 1 Partial pressure S...

Страница 145: ...of the CDEM anode with a boxcar or transient digitizer Use the ML0 command to turn off the RF DC bias when finished performing measurements and before quitting the program controlling the RGA It is go...

Страница 146: ...teway to error diagnosis Important The RGA is free of detected errors as long as the STATUS byte is clear no bits set Each bit of the STATUS byte reflects the result of a different type of internal ch...

Страница 147: ...P S problem The EP query command is then used to query PS_ERR Bit 6 of PS_ERR is found set Error Code PS6 indicating that the P S output is less than the acceptable minimum of 22 V This error is also...

Страница 148: ...e STATUS byte returned by the ER command has the bit 0 set as expected for a communications problem The specific communications problem is diagnosed using the EC command Bit 0 of RS232_ERR is found se...

Страница 149: ...quence 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 accept a...

Страница 150: ...es Make sure the RGA is powered up and ready to go Check the quality of the RS232 connection to the host computer Check the user s communication software to make sure it is communicating properly with...

Страница 151: ...ardware including the 24V P S the Electrometer 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...

Страница 152: ...s electron stimulated desorption Degassing is done in a very controlled fashion The electron emission current is ramped slowly to avoid sudden bursts of pressure into the vacuum chamber and the filame...

Страница 153: ...lished at the end Parameters DG0 Do nothing command Commonly used to stop degassing Nothing is echoed over RS232 DGparam param 0 20 The parameter represents the degas time in minutes The first minute...

Страница 154: ...current mA Echo STATUS error byte or query response Set the electron emission current level in the ionizer The parameter represents the desired electron emission current in units of mA When a finite e...

Страница 155: ...aram command The difference observed will never exceed 0 02 mA The value returned is the actual electron current circulating through the ionizer as internally calculated by the RGA ECU The discrepancy...

Страница 156: ...query response Set the focus plate voltage in the ionizer The parameter represents the magnitude of the biasing voltage negative in units of volts The ions formed inside the anode grid are extracted i...

Страница 157: ...rameter represents the magnitude of the focus plate bias potential in Volts The actual bias voltage is negative The STATUS byte is transmitted at the end of command execution VF The default Focus plat...

Страница 158: ...red after a complete recalibration CL of the electrometer is performed and also when the unit is turned off Use the CA command every time the detector settings are changed to values that have not been...

Страница 159: ...cking 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 calibratio...

Страница 160: ...lly 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 magnitude of t...

Страница 161: ...agnitude of the positive currents measured The HV_LED is turned off The STATUS Byte is sent out to prompt the end of the command HVparam param 10 2490 The parameter is the magnitude of the CDEM bias v...

Страница 162: ...iplier CDEM option in the RGA unit being programmed The RGA is provided standard with a Faraday Cup detector For increased sensitivity and faster scan rates an optional CDEM is offered The MO command...

Страница 163: ...ime or since the unit was turned on or recalibrated with the CL command See the CA command for details and more recommendations RGA Windows note When using the RGA Windows program to operate the RGA t...

Страница 164: ...are from scanning to MF with SA measurements steps per amu Each point transmitted represents an ion current and as such corresponds to 4 bytes being received by the host computer The AP query is used...

Страница 165: ...k The absence of a parameter i e HP is treated as a Bad Parameter error HSparam param 0 255 Description Histogram Scan Trigger Echo Ion Currents Excecute one or multiple Histogram Scans under the pres...

Страница 166: ...umber of scans specified by the parameter is executed Scanning is immediately stopped when a new command is received as in the case of continuous scanning HS The default parameter value is used for mu...

Страница 167: ...a stream is transmitted back to the host computer will minimize the problems that are associated to this feature MFparam param 1 M_MAX Description Final Mass amu of mass spectra Analog and Histogram E...

Страница 168: ...rameters MIparam param 1 M_MAX The parameter represents the initial scan mass in amu units The upper mass limit depends on the RGA model number M_MAX 100 for RGA100 200 for RGA200 and 300 for the RGA3...

Страница 169: ...he Miniscan covers a 0 6 amu range centered at the mass requested and selects the maximum current from 7 individual measurements performed at 0 1 amu mass increments The detector settings i e type of...

Страница 170: ...ng chapter of this manual if shifts in the peak locations are observed The RF DC voltages are left on at the end of a single mass measurement Use the MR0 command at the end of a set of measurements an...

Страница 171: ...rent is measured after each mass increment step and transmitted to the host computer over RS232 The mass range for the scan is set in advance with the commands MI Initial Mass and MF Final Mass and th...

Страница 172: ...arameters must be integers and within the specified range No query format is allowed for the parameter Programming Tips Any command received by the RGA while scanning will immediately stop the scan pr...

Страница 173: ...nt out over RS232 TP_Flag is set upon a power on reset and cleared when the CDEM is activated It can also be toggled on off by the user with the TP command The total ion current measured by the elctro...

Страница 174: ...lue is returned as a response to a total Pressure Measurement request note that this includes the total pressure measurement requests at the end of scans TP1 TP_Flag is set Total pressure measurement...

Страница 175: ...s only available in ECU s with a CDEM option Opt01 installed See MO command for details Parameters MGparam param 0 0000 2000 0000 The parameter interpreted as a CDEM gain in units of thousands is stor...

Страница 176: ...o Query Response Store a value of Partial Pressure Sensitivity expressed in units of mA Torr in the non volatile memory of the RGA ECU Important The sensitivity factor is not used internally by the RG...

Страница 177: ...onnected to the instrument Total Pressure Sensitivity factors are gas specific probe specific and highly dependent on the ionizer conditions and on aging of the probe Note The parameter loaded at the...

Страница 178: ...nst temperature fluctuations The result is very stable RF DC levels that are highly insensitive to the operating conditions of the RGA ECU Important The RF DC stabilization algorithm Step 2 above rema...

Страница 179: ...scription 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 based on...

Страница 180: ...lishes a finite electron emission current Consult the Error Byte Definitions section of this chapter for detatils on the different error bytes of the RGA Consult the RGA Troubleshooting chapter of thi...

Страница 181: ...he PS_ERR byte value is returned to the computer in ASCII format and with a LF CR terminator No errors are present as long as the byte value is zero Consult the Error Byte Definitions section of this...

Страница 182: ...R Description STATUS Byte Query Echo STATUS Byte Query the value of the STATUS Error byte The STATUS byte value is returned to the computer in ASCII format and with a LF terminator No errors are prese...

Страница 183: ...RGA Command Set 3 59 Technical Reference Error checking The only acceptable parameter is a question mark The absence of a parameter i e ER is treated as a bad parameter error...

Страница 184: ...he only acceptable parameter is a question mark The absence 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 JP10...

Страница 185: ...alibration parameters by inexperienced operators Setting JP100 will disable peak tuning of the ECU Parameters DIparam param 0 255 If Calibration is enabled by the jumper JP100 See CE Command the value...

Страница 186: ...m the value of the DS peak tuning parameter during the Peak Width Tuning Procedure The value is saved in the non volatile memory of the RGA ECU and used by the firmware to generate DAC8 m during measu...

Страница 187: ...he voltage output of the RF_Driver 0 amu during the Peak Position Tuning Procedure The value is saved in the non volatile memory of the RGA ECU and used by the firmware to generate the internal scan p...

Страница 188: ...he rods and the mass setting of the filter The 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 anal...

Страница 189: ...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 in t...

Страница 190: ...erent problems based on their Error Codes and suggests possible causes and solutions STATUS Error Byte General Status byte Each bit corresponds to a different type of internal check Bit Internal Check...

Страница 191: ...t Used 3 Not Used 2 Not Used 1 Not Used 0 Not Used DET_ERR Error Byte Electrometer Error Byte Bit Description Error Code 7 ADC16 Test failure DET7 6 DETECT fails to read 5nA input current DET6 5 DETEC...

Страница 192: ..._EXT 2V at M_MAX RF7 6 Primary current exceeds 2 0A RF6 5 Not used 4 Power supply in current limited mode RF4 3 Not Used 2 Not Used 1 Not Used 0 Not Used CEM_ERR Error Byte Electron Multiplier Error B...

Страница 193: ...ion current FL6 5 Vacuum Chamber pressure too high FL5 4 Not used 3 Not used 2 Not used 1 Not used 0 Single filament operation FL0 RS232_ERR Error Byte Communications Error Byte Bit Description 7 Not...

Страница 194: ......

Страница 195: ...s After Capillary Flow Valve Opened 4 2 Loud Noises While Shutting Down 4 3 Nothing Operates 4 3 Internal Error Detection in the SRS RGA 4 4 24V DC Power Supply 4 5 Electrometer 4 5 Quadrupole Mass Fi...

Страница 196: ...rbo Pump Does Not Reach Full Speed The turbo pump should accelerate to full speed in under two minutes An excessive gas load can prevent this from happening If the pump is not reaching full speed chec...

Страница 197: ...These noises are normal and of no concern Venting the system will cause the turbo pump to quickly decelerate and avoid the noise Nothing Operates If the main power switch does not light either the mai...

Страница 198: ...nt problems based on unique Error Codes Refer to the next section of this chapter for Troubleshooting information specific to each Error Code Users developing their own RGA control software should int...

Страница 199: ...with built in power modules Option Opt02 to check the voltage output of the internal switching power supply If a voltage out of the allowable range is found the POWER LED is turned off the red Error L...

Страница 200: ...Reporting Command EQ Error Codes prefix RF Power on check Yes The RF power supply that biases the rods of the Quadrupole Mass Filter is thoroughly checked upon a power on reset and can be tested at a...

Страница 201: ...re Filament not present burnt or not installed Unable to set the requested emission current If any of these two error conditions is detected while the filament is on the heater is immediately shut dow...

Страница 202: ...use A large offset input voltage is present in one or both of the I V converter op amps This problem results in electrometer calibration errors and will cause erroneous ion current readings Troublesho...

Страница 203: ...T6 Type of Error Electrometer Error Message Electrometer Error DETECT fails to read 5nA input current Error Cause The logarithmic output of the picoammeter is not within the levels expected for a 5 nA...

Страница 204: ...the electron multiplier are immediately turned off and the Error and Leak LED s are turned on to indicate the problem Important The Leak LED will also be turned on if the Thoria coating of the filamen...

Страница 205: ...still does not turn on contact SRS FL7 Type of Error Filament Background Protection Mode Error Message Filament Error No filament detected Error Cause No filament was detected after an attempt was mad...

Страница 206: ...is turned off and the Error LED is turned on instead Troubleshooting Check the voltage output of the external power supply with a voltmeter Adjust the voltage to 24 V in adjustable external supplies o...

Страница 207: ...t the problem by pressing the Help button This problem should not be ignored since it can be associated to erroneous readings at high masses Troubleshooting Are the electronics warmed up The RF P S is...

Страница 208: ...more warnings are posted beyond that point If no improvement in the mass range is seen as the unit warms up then go on with the troubleshooting procedure Is a probe connected to the ECU box The ECU s...

Страница 209: ...ng and Care 5 5 Handling and mounting 5 5 Operating Temperature Pressure 5 5 Operating Voltage 5 5 Initial pump down 5 5 Contamination 5 5 Storage 5 6 CDEM Pre conditioning 5 6 Accessing Internal Comp...

Страница 210: ...s are maintained Disconnect the ECU box from the probe before servicing any of the probe components Turn off the emission and wait for at least 30 minutes before removing a probe from a vacuum chamber...

Страница 211: ...Keeping the pump cool will also extend its operating life Good statistical data is not available for these pumps You can expect 1 year minimum and 2 years typical The performance of the pump can be di...

Страница 212: ...ased vacuum grease can be applied on the hose barb to improve the seal Reattach the sleeve When remaking the connection wet the outside of the hose with water to ease installation of the sleeve After...

Страница 213: ...Voltage The maximum voltage applied to any CDEM should not exceed 3500V The SRS RGA High Voltage power supply is limited to a 2500V output Typical operating range is 1100 2500V In general the lower th...

Страница 214: ...own and initial operation of a new CDEM 1 Pump overnight prior to initial application of voltage 2 Begin operation at the lowest voltage possible working up to the voltage required to produce observab...

Страница 215: ...move the screws around the perimeter of the painted metal cover 4 on back and 6 on bottom Slide the cover back about 1 4 inch Pull the bottom edges of the cover away from the chassis until the hooks o...

Страница 216: ...5 8 Accessing Internal Components SRS QMS Gas Analyzer Internal View Map of Internal Components...

Страница 217: ...e remaining screws on the front and two nuts on the inside top flange The two nuts require the socket wrench for easy removal Pull the front panel off a set aside 4 The RGA ECU is now exposed Remove t...

Страница 218: ...L bracket that is supporting the feedthrough end of the RGA probe If the chassis is laying on its side tip it up to remove the four screws and lay back down when done 2 At the flange connecting the RG...

Страница 219: ...can be detected by placing a bag over the fittings to produce a pure helium atmosphere around the suspect leak This process is not as fast as with the metal seals It can take several minutes for the h...

Страница 220: ...the voltmeter probes into the Analog Monitor and Ground test points The analog output should read 0 375 V Atmosphere Adjust With both valves closed remove the capillary or plug from the inlet This ex...

Страница 221: ...at can be safely used The valves contains a Viton seal and are rated to 120 C at the valve body The pressure gauge can only tolerate 85 C The flange of the turbo pump cannot exceed 120 C The bearings...

Страница 222: ...gas process the anode grid and the filament are bombarded by a 20 mA current of 400eV electrons The complete process takes three minutes and can be triggered directly from the RGA Windows software Hea...

Страница 223: ...gen 7 Place the CDEM in a clean Petri dish and dry at 100 C for about one hour Quadrupole Filter Cleaning The quadrupole mass filter is the heart of the RGA The sensitivity and resolution of the instr...

Страница 224: ...asive sheets 3200 to 12000 grit Ultrasonic cleaner Mr Clean detergent Acetone Electronic grade or better Methanol Electronic grade or better 1000 ml beaker Oil free dry nitrogen Distilled or de ionize...

Страница 225: ...apter Be very careful not to damage the thoria coating if you intend to use the same filament during reassembly Next remove the CDEM following steps from the CDEM Replacement procedure Store the multi...

Страница 226: ...ribed next Work on one spacer at a time using a single small turn of the screwdriver on each screw After a single round of eight screws hold a spacer in each hand and slightly torque the assembly back...

Страница 227: ...aligned Use an ohmmeter to make sure the electrodes are electrically isolated from each other and from the body of the flange ground 17 Once satisfied install the probe back in the vacuum system and...

Страница 228: ...ver 2 5mm head Needle nose pliers Latex gloves powder free 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 a...

Страница 229: ...ly 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 during this step but it does not need to b...

Страница 230: ...sually 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 flan...

Страница 231: ...nt and spare screws and nuts One standard OFHC copper gasket for 2 3 4 CF Flange New and Clean Precision flat head screw driver 2 5mm head Needle nose pliers Latex gloves powder free Clean dust free w...

Страница 232: ...atinum tabs spot welded at opposite ends of its circumference provide electrical connection to the rods that deliver the power during emission Precision machined slots define the exact placement of th...

Страница 233: ...lifetime of all electron multipliers Eventually the gain drops to unacceptable values and the multiplier needs to be replaced As a rule of thumb the CDEM should be replaced when the required gains ca...

Страница 234: ...or loose damaged misaligned and severely contaminated components Carefully inspect the ionizer and if any problems are detected perform a filament and or ionizer replacement following the procedures d...

Страница 235: ...small screw 13 Visually 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...

Страница 236: ...pro and Cajon parts are carried by your local Swagelok distributor diaphragm pump diaphragm rebuild kit contact SRS VCR gaskets 1 4 stainless steel w silver coating Cajon SS 4 VCR 2 RS gaskets BSP ISO...

Страница 237: ...the time to go through the different maintenance steps can choose to send the unit back to the factory for out of warranty service Please contact SRS to obtain information Important All users returnin...

Страница 238: ......

Страница 239: ...SRS QMS Gas Analyzer Technical Reference Appendix A System Electronics In This Chapter Description of Schematics A 2 Schematic MCA_C1 A 2 Schematic MCA_C2 A 3 Schematic MCA_D1 A 3 Parts List A 4...

Страница 240: ...tes of ROM and 32 bytes of RAM The 4 MHz crystal is the source of the mcu s 2MHz internal clock This mcu has 10 bits of I O Port A 0 7 and Port B 0 1 The mcu has built in power up delays The reset and...

Страница 241: ...nents R7 R8 C10 form a high pass filter and a divider The diode D2 clamps the adjust pin of the regulator This clamp protects the device when the valves are turned off While the solenoids require full...

Страница 242: ...rolytic 50V 20 Radial C 11 5 00192 542 22U MIN Cap Mini Electrolytic 50V 20 Radial C 12 5 00100 517 2 2U Capacitor Tantalum 35V 20 Rad C 13 5 00102 517 4 7U Capacitor Tantalum 35V 20 Rad D 1 3 00003 3...

Страница 243: ...00057 401 220 Resistor Carbon Film 1 4W 5 R 16 4 00057 401 220 Resistor Carbon Film 1 4W 5 R 17 4 00325 407 845 Resistor Metal Film 1 8W 1 50PPM R 18 4 00087 401 510 Resistor Carbon Film 1 4W 5 R 19 4...

Страница 244: ...Z 0 0 00436 052 6 1 2 22 WH Wire 22 UL1007 Z 0 0 00437 052 6 1 2 22 GR Wire 22 UL1007 Z 0 0 00466 050 23 18 BLACK Wire 18 UL1007 Stripped 3 8x3 8 No Tin Z 0 0 00467 050 23 18 RED Wire 18 UL1007 Stripp...

Страница 245: ...p MTA 156 Z 0 1 00317 179 2 PIN PLUG Connector Housing Receptacle Z 0 1 00318 179 2 PIN RECPTCL Connector Housing Receptacle Z 0 2 00044 211 1901 1102 Switch Rocker Z 0 7 00731 720 PRS 7 Fabricated Pa...

Страница 246: ...e ECU covers are removed In This Chapter Overview of the RGA B 3 Circuit Description B 4 General Description B 4 Circuit Boards B 5 Description of Schematics B 6 Schematic name QMSE_T1 B 6 Microproces...

Страница 247: ...Schematic name QMSE_V1 B 15 Signal Conditioning B 15 Schematic name QMSE_V2 B 17 Electron Multiplier High Voltage Power Supply B 17 Parts Lists B 18 Top Board Components Parts List B 18 Bottom Board P...

Страница 248: ...ods The selected ions are collected in a Faraday cup or multiplied in an electron multiplier The ECU box 3 x 4 x9 contains all the electronics necessary to operate the RGA It connects directly to the...

Страница 249: ...ds The potentials are given by Vx y t U V0 cos t where 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 instr...

Страница 250: ...ion circuit A small vertical PCB which holds the log I V converter 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 p...

Страница 251: ...e provided to the CPU by U100 a MAX705 Digital I O Ports The microprocessor s I O ports are assigned as follows PA0 RTS Low indicates that the host computer is ready for RS232 data PA1 BUSY Low indica...

Страница 252: ...In addition to the I O port on the microcontroller there are three 8 bit digital shift registers which are loaded via the SPI then strobed by a LD bit to transfer data to the parts output registers T...

Страница 253: ...ted for the following reasons 1 It is close to the maximum operating frequency for the 68HC11 12 MHz 2 When divided by four it provides a usable RF frequency 2 7648 MHz 3 When divided by 128 it provid...

Страница 254: ...their output voltages are nearly the same when there is no ion current being detected The outputs of each I V converter may be read via the 16 bit A D for calibration and offset nulling The outputs o...

Страница 255: ...en the system is reset until the CPU can establish the system environment Upon reset the dual flip flop U300 is reset The output of the second flip flop which controls all three channels of the analog...

Страница 256: ...detection gain potentiometer is very important in order to maintain constant resolution and sensitivity throughout a scan P300 should be adjusted so that He and Kr have the same resolution with RES_CT...

Страница 257: ...ge as measured at J400 which is RF_CT 5 Polypropylene capacitors with a voltage rating of 50V are used to tune the primary reactance for minimum power loss The 39 turn secondaries are wound in a very...

Страница 258: ...the filament temperature via the filament heater current s duty cycle A switching power supply which is synchronized to a sub multiple of the master clock at 172 8kHz is used to provide heater power...

Страница 259: ...on inverting input and so the output of the op amp U502B will go up increasing the current in the opto isolator s LED increasing Q502 s collector current increasing the magnitude of the negative repel...

Страница 260: ...protection is provided by U601 on a cycle by cycle basis U601 does not regulate the outputs of the inverter rather its COMP pin is tied high to provide the maximum duty cycle The first of three secon...

Страница 261: ...ding on the speed and sensitivity required for a scan High speed scans require high bias currents which reduce the time constant though the diode and high sensitivity scans require low bias currents t...

Страница 262: ...ly synchronized to a sub multiple of the master clock at 43 2kHz followed by a voltage multiplier is used to generate a negative high voltage The multiplier output is compared to the set level HV_SET...

Страница 263: ...50V 20 Z5U C 113 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 114 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 200 5 00100 517 2 2U Capacitor Tantalum 35V 20 Rad C 205 5 00051 512 015U Cap...

Страница 264: ...1N5711 Diode D 303 3 00203 301 1N5711 Diode D 304 3 00004 301 1N4148 Diode D 305 3 00203 301 1N5711 Diode J 100 1 00143 101 TEST JACK Vertical Test Jack J 101 1 00143 101 TEST JACK Vertical Test Jack...

Страница 265: ...4 00034 401 10K Resistor Carbon Film 1 4W 5 R 114 4 00034 401 10K Resistor Carbon Film 1 4W 5 R 115 4 00034 401 10K Resistor Carbon Film 1 4W 5 R 116 4 00034 401 10K Resistor Carbon Film 1 4W 5 R 117...

Страница 266: ...0K Resistor Metal Film 1 8W 0 1 25ppm R 227 4 00897 408 1 910K Resistor Metal Film 1 8W 0 1 25ppm R 228 4 00218 408 10 00K Resistor Metal Film 1 8W 0 1 25ppm R 229 4 00192 407 49 9K Resistor Metal Fil...

Страница 267: ...40 74HC4020 Integrated Circuit Thru hole Pkg U 109 3 00049 340 74HC74 Integrated Circuit Thru hole Pkg U 110 3 00039 340 74HC14 Integrated Circuit Thru hole Pkg U 111 3 00265 340 74HC595 Integrated Ci...

Страница 268: ...lyester C 412 5 00171 535 01U Capacitor Polypropylene C 413 5 00171 535 01U Capacitor Polypropylene C 414 5 00330 533 01U 400V 10 Capacitor Metallized Polyester C 415 5 00330 533 01U 400V 10 Capacitor...

Страница 269: ...or 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 Rad C 625 5 00100 517 2 2U Capacitor Tantalum 35V 20 Rad C 626 5 00100 517...

Страница 270: ...0264 131 20 PIN DI Connector Female JP500 1 00270 130 4 PIN SI Connector Male JP501 1 00270 130 4 PIN SI Connector Male JP600 1 00269 159 9 PIN Connector D Sub Right Angle PC Male JP601 1 00264 131 20...

Страница 271: ...sistor Metal Film 1 8W 1 50PPM R 404 4 00889 401 110 Resistor Carbon Film 1 4W 5 R 405 4 00138 407 10 0K Resistor Metal Film 1 8W 1 50PPM R 406 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 407 4 000...

Страница 272: ...tor 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...

Страница 273: ...sistor Metal Film 1 8W 1 50PPM R 534 4 00294 407 24 9K Resistor Metal Film 1 8W 1 50PPM R 535 4 00131 407 1 00M Resistor Metal Film 1 8W 1 50PPM R 536 4 00398 407 499K Resistor Metal Film 1 8W 1 50PPM...

Страница 274: ...Integrated Circuit Thru hole Pkg U 501 3 00634 340 3525A Integrated Circuit Thru hole Pkg U 502 3 00508 340 LM358 Integrated Circuit Thru hole Pkg U 503 3 00508 340 LM358 Integrated Circuit Thru hole...

Страница 275: ...tor Ceramic 1000 VDCW C 812 5 00143 536 1200P Capacitor Ceramic 1000 VDCW C 813 5 00143 536 1200P Capacitor Ceramic 1000 VDCW C 814 5 00143 536 1200P Capacitor Ceramic 1000 VDCW C 815 5 00143 536 1200...

Страница 276: ...9 D44VH10 Voltage Reg TO 220 TAB Package Q 402 3 00629 329 IRF510 Voltage Reg TO 220 TAB Package Q 403 3 00629 329 IRF510 Voltage Reg TO 220 TAB Package Q 500 3 00283 340 IRF530 IRF532 Integrated Circ...

Страница 277: ...42 407 100K Resistor Metal Film 1 8W 1 50PPM R 814 4 00047 401 2 2 Resistor Carbon Film 1 4W 5 RL700 3 00523 335 G6AK 234P ST UC Relay RL701 3 00523 335 G6AK 234P ST UC Relay RL702 3 00523 335 G6AK 23...

Страница 278: ...D AUDIO 1PR Cable Coax Misc Z 0 0 00638 055 HV UL3239 Wire Other Z 0 1 00230 100 1 6 65 Connector Misc Z 0 1 00277 170 RS232 SER DB9 Cable Assembly Multiconductor Z 0 1 00279 100 DB9M DB25F Connector...

Страница 279: ...schematics refered to in previous chapters System Schematics QMS Wiring Diagram Microcontroller PCB Diagram MCA_C1 MCA_C2 MCA_D1 Probe Drawings Feed through Flange Connectors Probe Assembly RGA Schem...

Страница 280: ..._________________________________________________ _______________________________________________________________________ _______________________________________________________________________ 1 Was...

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