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Operation Manual and

Programming Reference

Universal Gas Analyzers

UGA100, UGA200, UGA300

Stanford Research Systems

Revision 1.6

Feb., 2018

Summary of Contents for UGA100

Page 1: ...Operation Manual and Programming Reference Universal Gas Analyzers UGA100 UGA200 UGA300 Stanford Research Systems Revision 1 6 Feb 2018...

Page 2: ...m the supplier Con tact Stanford Research Systems or an authorized representative before returning this product for repair Trademarks Ultra Torr and VCR are registered trademarks of Swagelok Co Tygon...

Page 3: ...nt Panel Operation 2 3 Remote Operation 2 17 Chapter 3 Remote Programming Introduction 3 2 Commands 3 4 Chapter 4 UGA Error Messages Introduction 4 2 Error Messages 4 3 Chapter 5 Calibration and Input...

Page 4: ...e used for lifting Do not move when system is running Line Voltage The UGA system is specified for line power of either 110 V 60 Hz or 220 V 50 Hz All the components inside the instrument will only be...

Page 5: ...s Analyzers iii Symbol Description Alternating current Caution risk of electric shock Frame or chassis terminal Caution refer to accompanying documents Earth ground terminal Battery Fuse On supply Off...

Page 6: ...lder installed Control cord installed Power cord for the controller installed RS232 communication cord for the controller installed Accessory box Channel plug 2 pkg 2 1 16 OD 175 mm ID capillary unhea...

Page 7: ...ity of the materials in our system with the specific corrosive environment The UGA system contains the following materials Body 304 stainless steel high vacuum tube 316 stainless steel quarter inch tu...

Page 8: ...Detection limit 10 ppm with Faraday cup detector 1 ppm with electron multiplier Operating pressure 10 4 mbar for FC 10 6 mbar for CDEM Connections Inlet 1 8 inch Ultra Torr fitting Exhaust 1 4 inch T...

Page 9: ...l stop Max Ambient Operating 35 C Temperature Power requirement either 110 V 60 Hz or 220 V 50 Hz not field selectable less than 600 W total Dimensions 28 cm H x 30 cm W x 65 cm D 11 in H x 12 in W x...

Page 10: ...Stanford Research Systems UGA Series Universal Gas Analyzers viii...

Page 11: ...e PC through Ether net connection If you find any damage to the UGA do not proceed and call SRS at the number below For detailed control procedures please refer to Chapter 2 Front Panel Operation of U...

Page 12: ...etup Ethernet paramters IP address Subnet Mask Gateway Username and Password properly at UGA Please refer to the sec tion 2 3 3 1 of this manual for detailed information Connect the provided Ethernet...

Page 13: ...select New UGA item See the following pic ture Then the UGA1 window will appear Click on the Main tab and select Connection Settings The Connection Settings dialog box will pop up as shown below In t...

Page 14: ...ort changes status to Connected the icon turns green close the ConnectorDialog window The title bar of the software indicates the present connection In the UGA software See screenshot on the next page...

Page 15: ...the Launch RGA button The RGA soft ware automatically connects to RGA through UGA From the RGA software click the filament button on the toolbar to activate the ionizer See the next figure Click the G...

Page 16: ...to the UGA control software and prepare for atmo spheric sampling In order to open the sample valve click on the Sample Valve item in the operation window After clicking on the item you will see a dr...

Page 17: ...system will read approximately 1 5 Torr at the bypass line and 5 X 10 6 Torr for the mass spectrometer chamber if you use the provided capillary In the RGA software start scan again by clicking the GO...

Page 18: ...Stanford Research Systems UGA Series Universal Gas Analyzers Quick Start xvi...

Page 19: ...2 1 2 Configuration 1 6 Front panel 1 6 Rear panel 1 7 Top front components 1 8 Top back components 1 10 Bottom components 1 10 Covers 1 12 Miscellaneous parts 1 12 1 3 Options Sample Heater Accessor...

Page 20: ...p to 25 ms per point The SRS UGA systems enable many new applications where tradi tional mass spectrometers were too large and heavy More recently a variety of applications for atmospheric sampling we...

Page 21: ...dling system consists of a capillary a pinhole pumps and valves that deliver the sample gas to the analyzer The UGA employs two separate diaphragm pumps DP for each stage In this way the high pressure...

Page 22: ...r range a low vacuum inlet assembly can be designed using appropriately sized tubing 0 063 inch OD to 0 125 inch OD and a valve The assembly can be attached to the port with a 2 75 inch CF flange Prop...

Page 23: ...e an enclosure of 12 W X 11 H X 25 L The system is designed to run in either horizontal or vertical orientation See figure 1 2 This flexibility in the operating orientation means it can fit almost any...

Page 24: ...pper panel has two holes one for capillary con nection and another for a DB9 connector which connects the cap illary heating control cables heater power and thermocouple ca bles The lower panel holds...

Page 25: ...al ground knob and a fan for the power distribu tion PCB on the rear upper panel There are two BNC connectors an analog output and a user interlock Two exhaust ports for the Bypass pump and the Roughi...

Page 26: ...bypass valve BV and bypass line The sample line set the RGA analyzer and the chamber heater are attached to a 2 75 cubic chamber as shown in Fig 1 5a These components are covered by the heat insulatin...

Page 27: ...A Series Universal Gas Analyzers UGA Basics 1 Figure 1 5b Top Front Area after the heat insulating box is installed Sample line heater Sample heating jacket Figure 1 5c Picture of the sample line heat...

Page 28: ...tribution PCB Fig 1 6 This volume houses vacuum control and system control consisting of TP connection elbow with its heater ELB TP Diaphragm pump for the bypass line BP Diaphragm pump of TP backing R...

Page 29: ...g fan On the elbow a heater for system baking is attached The elbow area is surrounded with an insulating box Fig 1 7a PVC tubes are used to connect exhaust lines and the system vent ing line If Optio...

Page 30: ...slot for multi capillaries con nection See Fig 1 8b A 6 capillary of 175 mm ID and 1 16 OD is provided for atmo spheric pressure sampling A 25 long RS 232 DB9 cable a power cord two dowel pins for sam...

Page 31: ...ectors for the valve outlet and the UGA inlet 3 1 16 OD 175 mm ID capillary unheated with a connector 3 ea Self control accessory box Related hardware The multiple inlet valve system is installed on t...

Page 32: ...r insulator box and the roughing connector are assembled together with TP controller inside the system Parts Capillary with heater Washer thermocouple 6 Sample line heater Bypass line heat jacket Pinh...

Page 33: ...9040 www thinkSRS com UGA Series Universal Gas Analyzers UGA Basics 1 15 Fig 1 9 Capillary with heater The connector for heater power and TC is also shown Figure 1 10 Components for sample line heati...

Page 34: ...capillary if the capillary was connected Take out the Ultra Torr insulator from the removed capillary if the capillary was connected Pull out the capillary through the capillary heater if the capillar...

Page 35: ...Phone 408 744 9040 www thinkSRS com UGA Series Universal Gas Analyzers UGA Basics 1 17 Figure 1 12 Final shape of Heated capillary connection...

Page 36: ...Stanford Research Systems UGA Series Universal Gas Analyzers UGA Basics 1 18...

Page 37: ...tus Keypad 2 3 Control Keypad 2 4 Front Panel Menu System 2 7 Entering Menu System 2 7 Menu Navigation 2 7 Automatic versus Manual 2 8 Manual Pump Down Procedure 2 8 Base pressures 2 9 Manual Venting...

Page 38: ...to Sample Valve 2 16 Auto Vent Valve 2 16 2 3 Remote Operation 2 17 Overview 2 17 Installation of Software 2 17 Connection to a PC 2 19 TCP IP Connection 2 19 RS232 Serial Connection 2 26 Menus and Di...

Page 39: ...r vacuum control After the system is in the Ready state it can perform the function of analyzing gas running the RGA and collecting data The UGA allows automatic control and individual control Automat...

Page 40: ...display of the control keypad which is beside the status keypad You can navigate the menu system on the control keypad or use the shortcuts on the sta tus keypad for quick access Fig 2 1 The Status K...

Page 41: ...fferent dis play pressures temperatures etc using the menu system there fore we refer to a selected display when discussing the menu sys tem below You can also cycle through the info displays Pressure...

Page 42: ...s shown on the display for 4 seconds The warning error means the unit can not process a command due to the restrictions of the process a command syntax error or no com ponent installed Because the war...

Page 43: ...the user makes a change from the control menu the dis play changes from the menu system to the selected display From non control menus the user must hit the Level up button repeat edly to return to th...

Page 44: ...Wake button on the control keypad 1 Enter the UGA menu system push the Level up button on the control keypad 2 Enter the Display menu and select Pressure 3 Push the Bypass Pump button on the status k...

Page 45: ...ad 22 Turn on the IG with the control keypad 23 At this point it is safe to put the roughing pump in idle mode This prolongs pump life Push the Roughing Pump RP button on the status keypad 24 Change t...

Page 46: ...ush the Sample Valve SV button on the status keypad 2 Close the SV with the control keypad 3 Push the Bypass Valve BV button on the status keypad 4 Close the BV with the control keypad 5 Push the Bypa...

Page 47: ...keypad 6 Turn off the BP with the control keypad 7 Push the RGA button on the status keypad 8 Turn off the RGA with the control keypad If the stability of RGA is concerned the user can let the filame...

Page 48: ...m bake During this process the system bake LED will blink and the sample heat LED is off After the UGA reaches the proper setting the sample heat LED will be lit and the system bake LED will remain li...

Page 49: ...he control keypad The analog out BNC on the rear panel of the UGA will give a volt age proportional to the leak signal The logarithmic value of this level is converted to an analog voltage signal from...

Page 50: ...se of a noraml TP In the sample heaters accessory two heaters the capillary heater and the sample line heater will be added to the UGA system The heat ing temperatures can be set from 40 C to the maxi...

Page 51: ...e the RGA will not be on when TP is not at full speed or in the idle state during the auto controls When the status of a component is set to change the UGA checks the present conditions to determine w...

Page 52: ...ing necessary to reach a state in which the valve may be opened This may require turning on the bypass pump and opening the bypass valve before opening the sample valve When the sample valve is closed...

Page 53: ...ser to track exactly where a problem began instead of guessing what went wrong This can save hours of time in debugging a vacuum process In order to obtain RGA data the UGA needs to be connected to a...

Page 54: ...efault directory for the installation is C Program files SRS UGA You may change the installation directory during this process but SRS recommends using the default directory 3 At the end of the instal...

Page 55: ...Refer to your network administrator for appropriate values for your network IP address 0 0 0 0 Subnet Mask 255 255 255 0 Gateway 0 0 0 0 2 Once you obtain these parameters enter them through the fron...

Page 56: ...rial port the TCP IP parameters IP address Subnet Mask Gateway User ID and Password can be typed in from the software using the Wizard menu in the UGA control software The Wizard menu can be used only...

Page 57: ...t of the Network tab in the Wizard dialog box Click the Security tab type in User ID and Password Fig 2 6 Screenshot of the Security tab in the Wizard dialog box When finished click the Done Button Ch...

Page 58: ...UGA and a PC If the connection is active the yellow LED will be lit on the RJ45 connector In the Main menu select Connection Settings The Connection Settings dialog box will pop up as shown in Fig 2 7...

Page 59: ...of the User Info box for TCP IP connection Type in the proper IP Address User ID and password the same ones set in the UGA Then click Apply The connection settings dialog box should have the informati...

Page 60: ...shown If the resources are not shown immediately click Update several times Choose the TCP IP connector by clicking on the connector column Then click Connect The connector icon will change to indicat...

Page 61: ...Ethernet connection On the title bar the connection status is shown 4 Now a user can explore the program by clicking each item on the graph Refer to the next section Menus and Displays for detailed i...

Page 62: ...nt panel 1 Connect between UGA and a PC using the provided serial cable 2 Power up the UGA 3 From the front panel choose the baud rate as follows The default rate is 38400 Push the Level up button to...

Page 63: ...he Connect button In the example screenshot above the UGA is found on COM1 Note if you are using a USB to serial adapter you must know what COM port the USB driver has allocated Use the Windows device...

Page 64: ...bar the connection status is shown The UGA control program is Windows based software written in the C language using NET framework The main user interface window is composed of several areas Title ba...

Page 65: ...me for each numbered section is written below 1 Main title bar 2 Menu bar 3 UGA instrument number tap 4 Message board 5 Log board 6 RGA software launch button 7 State indicators for components and opt...

Page 66: ...ew UGA Close UGA and Quit Connect submenu connects UGA to a PC through the assigned connection TCP IP Ethernet or RS232 Serial Connection Settings provides the selection of the connector the connector...

Page 67: ...essage log contains all the events of component controls with time stamp which are shown in 5 the log board of Fig 2 16 In the data log there are 8 data 3 pressures roughing line bypass line and RGA c...

Page 68: ...the options for displaying pressure and temperature data on the Operations and displays sub window 8 on Fig 2 16 If a user checks Dock View after selecting some items from the left box the related da...

Page 69: ...thinkSRS com UGA Series Universal Gas Analyzers Guide to Operation 2 33 Fig 2 20 Screenshot of the Instrument Settings dialog box showing the Graph tab Fig 2 21 Screen shot of the Settings dialog box...

Page 70: ...rature Fig 2 22 Screen shot of the Settings dialog box showing the Heaters tab If O100HC is ordered the system has two more heaters sample line heater and capillary heater in addition to the baking he...

Page 71: ...2 35 Fig 2 23 Screenshot of the Settings dialog box showing the Unit tab Fig 2 24 Screenshot of the Settings dialog box showing the Misc tab In the Misc tab several display items can be selected Elap...

Page 72: ...e board all error and warning messages are shown If enabled the messages will be recorded in the message log file 5 Log board In the Log board every event will be written with the time stamp If enable...

Page 73: ...using now There are two filaments in an ion gauge The filament can be selected from the UGA front panel or from the operation window of UGA control software If the LED for Multiple Inlet is green it m...

Page 74: ...he buttons on the front panel with an additional Bake On Off button Only the ap plicable mode buttons are activated depending on the status of the UGA The others will be grayed out and will be disable...

Page 75: ...m within UGA control software Check that the connection is established Check that the RGA is on If not turn it on by clicking the RGA item in the operation window Fig 2 27 Check the RGA status in the...

Page 76: ...to ready state Establish RS232 serial connection between UGA and the PC Start RGA exe Click the connection button the toolbar The following dialog box will appear Fig 2 28 Screenshot of RGA connectio...

Page 77: ...then new data input dialog box will appear Fig 2 30 Fig 2 30 Screenshot of Ethernet data input dialog in RGA exe Type in the same network settings as the settings in UGA and click OK The port value sh...

Page 78: ...e Operation sub window Click ing the entry for the Multiple inlet valve on the Option section of the Operation sub window will display the channel selection menu See Fig 2 32 Select the desired channe...

Page 79: ...ntrol software click the vent valve Fig 2 33 Choose the appropriate action menu item OFF or ON When ON is selected the UGA will first open the valve for 1 second Then it will wait for 40 seconds to op...

Page 80: ...Temperature item Type in the desired temperature settings The heating temperatures can be set from 40 C to the maximum of 100 C This temperature limit is important for the valves Sample valve Bypass v...

Page 81: ...t 3 3 Command format 3 3 Command syntax 3 4 3 2 Commands 3 5 Mode setting commands 3 4 ZMST 3 5 ZMSP 3 6 ZMST 3 6 ZMLT i 3 6 ZMBK i 3 7 ZMOD 3 7 Components control commands 3 8 ZCBP i 3 8 ZCRP i 3 8 Z...

Page 82: ...17 Error query commands 3 17 ZERR 3 17 ZEDS i 3 17 Parameter setting commands 3 18 ZPBO i 3 18 ZPRO i 3 18 ZPRI i 3 18 ZPBA i 3 18 ZPIP i i i i 3 19 ZPSM i i i i 3 19 ZPGW i i i i 3 19 ZPNM s 3 20 ZPP...

Page 83: ...smission Ground is pin 5 The UGA uses hardware handshaking one stop bit no parity baud rate either 28800 or 38400 A user may connect the UGA either directly to the host comput er with a cross over cab...

Page 84: ...d omitting the de sired parameter from the command Values returned by the UGA are sent as a string of ASCII characters terminated by a carriage return CR The four letter mnemonic shown in CAPS in each...

Page 85: ...in name and password Commands to set values which may be different for each channel require the p parameter These values must be queried separately for each channel All numeric variables should be exp...

Page 86: ...ing 42 Example ZMSL begins SLEEP mode Errors and warnings The command is ignored if any of these conditions are true Warning 42 Turbo not ready Warning 47 Leak Test ON Warning 48 System Bake ON Leak T...

Page 87: ...mmand is ignored if any of these conditions are true Warning 47 Leak Test ON Warning 51 Pressure Check off System mode query The ZMOD Query returns the current UGA mode described below Off 1 all compo...

Page 88: ...rning 48 System Bake On Error 96 CM malfunction Error 98 BP too high Roughing pump Off On Idle The ZCRP i command turns the roughing pump Off i 0 On i 1 or Idle i 2 The ZCRP query returns whether the...

Page 89: ...true ZCTP 0 Warning 43 RGA ON Warning 46 IG ON Warning 48 System Bake ON Error 110 TP stop failed With Error 110 the ZCTP query returns Error state 12 until the turbo pump is turned off ZCTP 1 Warnin...

Page 90: ...Error 99 BV too high Sample valve Off On The Sample valve operates differently depending on the automatic sample valve states associated with ZPAS command 1 With the automatic sample valve Off The ZC...

Page 91: ...the RGA On ZCRG Returns the state of the RGA Errors and warnings The command is ignored if any of these conditions are true ZCRG 0 Warning 47 Leak Test On Error 80 RGA off failed ZCRG 1 Warning 42 Tur...

Page 92: ...his command goes in the cycles not to vent the chamber too fast while the turbo pump is running in full speed ZCVV returns 1 through the whole cycles and return 0 after the final closure Errors and Wa...

Page 93: ...ontrolled to the sample heat temperatures set by ZPTH command Errors and Warnings The command is ignored if any of these conditions are met Error 61 Heater initialize ZCHT 0 Warning 48 System Bake ON...

Page 94: ...returns an integer that contains the following bit information Bit Name Bit Number Bit set on STATE_BIT_ERROR BIT15 Any error condition STATE_BIT_POWER BIT14 Power up STATE_BIT_AUTO BIT13 Automatic mo...

Page 95: ...bit is set it indicates the corresponding component is in transition either from Off to On or from On to Off and also either from Closed to Open or from Open to Closed Once the transition is over the...

Page 96: ...e reading in mTorr Index 1 N A Index 2 CM gauge reading in mTorr Index 3 IG reading in pTorr If the corresponding gauge is not on the reading is meaningless Example ZQAD 0 If the command returns 10000...

Page 97: ...rature in degrees Celcius Remaining bake time The ZQBR query returns baking time remaining in minutes Error query The ZERR queries Error code Whenever ZBST Bit 15 is set use ZERR to read errors Latest...

Page 98: ...30 to 100 i 100 The ZPRO query returns the current on power setting for the roughing pump The parameter change is immediately effective all the time even the roughing pump is running The default setti...

Page 99: ...192 168 1 12 Sets the IP address to 192 168 1 12 Errors and Warnings The command is ignored if the following error is issued after the command input ZPIP i i i i Warning 16 Bad parameter IP Subnet Ma...

Page 100: ...ric characters a z A Z and 0 9 The login name should be 15 characters or less The default is SRSUGA Examples ZPNM SRSUGA Sets the login name to SRSUGA ZPNM Clears the login name With blank login name...

Page 101: ...ue is full duplex The ZPDU queries whether the Ethernet is full duplex or half duplex Ethernet Speed Auto 10 Mbps 100 Mbps The ZPSP i command sets Ethernet speed Auto negotiation i 0 10 Mbps i 1 or 10...

Page 102: ...uence ends without opening the vent valve Automatic sample valve The ZPAS i command changes the the automatic sample valve option to Off i 0 or On i 1 The ZPAS query returns the current value of the o...

Page 103: ...mber heater 1 The parameter i is a set temperature in Celsius for the heater p and ranges from 0 to 120 The default value for the parameter i is 105 If a set value for a heater is 0 the heater stays o...

Page 104: ...Sets the sample mode set temperature of the sample line heater to 80 C ZPTH 2 Returns the sample mode set temperature of the sample line heater Errors and Warnings The command is ignored if this cond...

Page 105: ...es In This Chapter This chapter lists and explains all the error messag es displayed on the UGA 4 1 Introduction 4 2 4 2 Error messages 4 3 Communication errors messages 4 3 Warning error messages 4 5...

Page 106: ...issued when UGA is not able to carry out a command sent over the remote interface or a menu selection chosen from the front panel With a warning the warning LED flashes for 4 seconds a warning sound...

Page 107: ...mand was issued as a set 12 Reserved 13 Missing Parameter A second parameter in a set command is missing 14 Extra Parameter Extra character s follow a valid command 15 Out of range A parameter is out...

Page 108: ...mmands to process in time Some of the commands are rejected 25 RGA unavailable RGA is not available to communicate when transitioning between power on and off or transitioning into and out of leak tes...

Page 109: ...mp is not allowed to turn on or idle when the bypass pump is not on and the bypass valve is open 34 Sample valve OPEN 1 The bypass valve is not allowed to CLOSE when the roughing pump is not off and t...

Page 110: ...d to turn off when the ion gauge is on 47 Leak Test ON When the leak test is running the following actions are not allowed 1 Start and sleep automatic sequences are not allowed to start 2 The system b...

Page 111: ...to initiate with Pressure Interlock off 52 Leak test timeout Communication time out occurred during Leak Test It may happen once in a while If it happens every 10 second or so the communication betwee...

Page 112: ...d 64 Sample Heater T C The thermocouple sensor attached on the sample line is an open circuit The temperature cannot be read 65 Capillary Heater T C The thermocouple sensor attached on the capillary i...

Page 113: ...urned off in time probably due to miscommunication between the main control board and the auxiliary control board 79 Reserved 80 RGA off failed The RGA is not turned off in time probably due to miscom...

Page 114: ...tected 93 No PG filament The detected current through the Pirani gauge is too small this probably means the PG filament is damaged 94 PG short circuited Too much current flows through the Pirani gauge...

Page 115: ...pump is not off The sample valve closes with this error 101 BP too low The sample line pressure is below 0 5 Torr for 2 seconds when the sample valve is open and the roughing pump is not off This happ...

Page 116: ...aring temperature is higher than 60 C 115 TP hot Turbo pump heat exchange temperature is higher than 60 C 116 TP start Turbo pump did not reach the full speed at run up time 117 TP input voltage TP co...

Page 117: ...ement Example 5 8 Calibration 5 9 Effect of Total Pressure 5 10 Operating off the Design Pressure 5 11 Total Pressure and Composition 5 12 5 2 Calibration of Partial Pressure 5 13 Initial Calibration...

Page 118: ...com mended Practice for the Calibration of Mass Spectrometers for Par tial Pressure Analysis Update to AVS Standard 2 3 For information on multiple linear regression analysis consult William H Press e...

Page 119: ...red Notes on Fragmentation Patterns The electron impact type of ion izer used in modern RGA s almost always causes more than one kind of ion to be produced from a single type of gas molecule Mul tiple...

Page 120: ...e assumption stated above can be written as the following linear equation HM g hMg 1 where g is an integer variable that represents the gases present i e assign an integer to each gas starting with on...

Page 121: ...ral scan Please see the RGA On Line Help files for details Standard fragmentation patterns for example the fragmentation patterns included in the RGA Library of RGA Windows can be used as a source of...

Page 122: ...s must be obtained under the same operating con ditions that will be used during general partial pressure analysis since they depend on many instrumental parameters including ionization energy emissio...

Page 123: ...y are to be expected above 10 5 Torr due to space charge effects in the ionizer and ion neutral scattering inter actions in the filter A more thorough check of the RGA s sensitivity involves measuring...

Page 124: ...itor them The scaling factors can also be adjusted to correct against the mass discrimination of the electron multiplier s gain Important Following current industry standards the partial pres sure sen...

Page 125: ...ic recalibration is necessary For careful quantitative analysis it is important that the sensitivity of the RGA be determined for every gas which may be a component of the system Each gas component in...

Page 126: ...armed up with the filament on and under typical operating con ditions for at least one hour Increasing the total pressure at the inlet of the capillary will in crease the flow through the capillary Th...

Page 127: ...to the capillary can be applied up to 10 mbar Because the UGA has a separated bypass pump the inlet pressure can go as high as turbo pump could hold the proper pressure for the RGA below 1x10 4 mbar O...

Page 128: ...design of capillaries The RGA measures partial pressure of the components in a gas stream For ideal gases the partial pressure is related to composi tion by where Pi is the partial pressure of the i...

Page 129: ...be found in the texts listed in the Reference section All quantitative calculations performed with the RGA rely on the assumption that there is a linear relation between the partial pres sure and the...

Page 130: ...another reference pres sure and allow both factors to be accurately determined it has no practical benefit Because only the ratio of the two factors is relevant strictly speak ing one of the factors c...

Page 131: ...reak into molecular fragments in the ionizer For common gases fragmentation factors exist that indicate what fraction of the molecules remain intact For nitrogen 92 6 of the molecules will remain inta...

Page 132: ...ca librate the UGA 1 Make sure that the pressure reduction factor is enabled and correct in the dialog box that appears under the Utilities Pressure Reduction menu item 2 Setup the UGA to sample the r...

Page 133: ...by the user The software only allows this value to be changed via the Sensitivity Tuning dialog box using a reference gauge reading Us ers cannot type a new value into the Sensitivity Factor text box...

Page 134: ...thod be aware that the UGA continuously draws 1 5 milliliter per minute of gas depending on the capillary The reservoir should be large or the total pressure will change quickly Even with the sample f...

Page 135: ...he data displayed must be a complete scan and be measured with the same parameters as the scans to follow 2 Under the Utilities menu select Background and select Scan Data Background from the dialog b...

Page 136: ...s complicated and requires understanding of the mass spec trum For instance in a 50 50 mixture of nitrogen and carbon di oxide you cannot use mass 28 to measure the nitrogen With this mixture about 10...

Page 137: ...ture Two approaches can prevent this problem con trol the location of condensation or prevent condensation The first approach can be very simple place screens or metal plates before the inlet to provi...

Page 138: ...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 30 seconds To locate the leak you would either have to move incredibly slow o...

Page 139: ...length of tube is related to the flowrate and dimensions by 1 where Q is the throughput C is the conductivity and P is the pressure drop Throughput is a measure of mass flowrate com monly used in vac...

Page 140: ...ows through the capillary Q C P P C P total cap a b cap a 2 Because Pa Pb the approximation can be made When the flow reaches the aperture it is split into two streams bypass and sample The sample flo...

Page 141: ...constant at 80 liter s 1 except for He and H2 The speed of the diaphragm pump is not a constant it is a function of the inlet pressure A typical speed curve is shown in the graph below inlet pressure...

Page 142: ...lary and largely con trolled by the aperture Choosing a different aperture has insignifi cant effect on the remainder of the system The mass flowrate through the capillary is insensitive to changes in...

Page 143: ...illaries are always cho sen to draw volumetric flowrates of 1 10 ml min 1 The complete speed curve would keep increasing up to the pumps specification of 13 liter min 1 at atmospheric pressure The ult...

Page 144: ...limit mainly will age the bearings more quickly The only advantage to operat ing the turbo pump at higher exhaust pressures is an increase in the flow rate through the capillary The higher flowrate ca...

Page 145: ...pressure exit pressure and flowrate These three values allow the conductivity to be determined equation 1 A typical design point is an exit pressure of 1 2 mbar and a corre sponding flow rate of 1 5...

Page 146: ...inch this uncertainty causes the conductivity to vary by about 40 Use the standard formulas as a guide but cut the capillary long to begin with Measure the actual perfor mance and trim as necessary Th...

Page 147: ...Thereby until the capillary be comes very long it is not an important contributor to the response time of the UGA Users will find vendors of gas chromatography supplies a good source for capillaries...

Page 148: ...ubing This can be accomplished as long as the extension is added to the vacuum side of the capillary Fig 5 6 Good and bad methods of adding an extension of vinyl tubing to the capillary The incorrect...

Page 149: ...ns Vacuum Diagnosis Studt R D Magazine October 1991 p 104 Design Away Those Tough Vacuum System Riddles Applications of RGAs to process control O Hanlon J Vac Sci Technol A 12 4 Jul Aug 1994 Ultrahigh...

Page 150: ...tiple linear regression analysis algorithms William H Press et al 1992 Numerical Recipes in C The Art of Scientific Computing Second Edition Cambridge Univ Press sec tion 15 4 page 671 Bevington P R 1...

Page 151: ...Input data 0 0 0 0 one level up Login Name Input data SRSUGA one level up Password Input data SRSUGA one level up Display Pressure Select a unit Torr Pascal mbar bar go to Pressure Display default dur...

Page 152: ...a parameter Fil 1 Fil 2 one level up Heaters Off Turn off all the heaters go to the selected display Bake Turn on Baking heaters go to the selected display Heat Sample Turn on Sample heaters if instal...

Page 153: ...tes But during LEAK TEST the system can go to STOP As can be seen below all fundamental modes can be reached from another The UGA can be stopped from any condition The stop command is handled on an em...

Page 154: ...the table below are the results of the 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 Al though...

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