WEPD23
Contents
1. gas for safety The GUI for the gas fill is shown in Fig 5 Post gas fill parameters of the system are shown via GUI shown in Fig 6 This also logs the data to the log file Front Panel for Display of Laser Maintenance Parameters Other system maintenance parameters such as gas pressures filter ratio lifetime of the halogen filter total laser pulses pulses after refill tube temperature etc can be displayed By using the STARTRP command these parameters can be logged into an Excel file for laser maintenance purposes The flow chart for this GUI is shown in Fig 6 UUL PUR CALIPICN LASER PORT INTIALIZATION MONITOR ALL PARAMETER GAS FILL OPERATION ENERGY CALIBRATION STOP HELP BEG 3 mJ Repeat 86 10 Hz Hi 30 kY Selec Mode RER LEE Figure 8 Front panel of Monitor and laser Set parameter ISBN 978 3 95450 124 3 48 Proceedings of PCaPAC2012 Kolkata India MODULE FOR LASER MONITOR AND SET PARAMETERS This GUI is basically to display the various operating and set parameters of the laser Parameters such as laser energy laser repetition rate and mode of operation Constant energy or constant voltage can be set Also there is an option to activate the burst mode operation of the laser if desired so by the user Flowchart for this GUI is shown in Fig 7 Front panel for this is shown in Fig 8 There are four basic operating modes under Select Mode viz HV PGR HV NGR constant voltage mode2. this Virtual Instrument driver VD file all the Sub VI drivers for different commands related to the excimer laser operation have been developed and incorporated The VI Tree showing the various VI s generated for compiling this GUI depicted schematically in Fig 13 Flush Command There are four Flush commands are used to flush gas lines of the various gases used for operation of the excimer laser Halogen Buffer Rare and Inert gases Write Command The four sub routines under this VI are set control functions related to running of the laser ie Run Laser Stop Laser Change value of HV Repetition Rate Latest Trends in GUI WEPD23 Read Command All parameters like operation mode mode repetition rate HV Energy Pressure System time and date tube temperature etc of excimer laser are read by running this VI LOGICAL SUB ROUTINES There are five sub routines under this VI Password sub VI is used for the security purpose Call VI is used for to call VI from folder where it has been saved Regression is used to find relation between two parameters by linear fit Mathematics These sub VIs are used for to estimate mean min max standard deviation and slope for data in the energy calibration operation Save file All data logging operations are carried out by this VI Multi Y axes Graph All multi X Y graphical representations are carried out by this VI Steps for Gas fill
3. with and without gas purge EGY PGR EGY NGR constant energy mode with and without gas purge for setting the running mode for the excimer laser At a time only one of the four options can be activated and can be changed only after laser is in off mode MODULE FOR LASER ENERGY CALIBRATION The internal energy meter of the excimer laser taps a small percentage of the laser beam to monitor the beam energy This is used for stabilizing the laser output Over time the calibration of this internal energy meter deteriorates and needs to be corrected over time The calibration of the internal emergy meter can be done against a pre calibrated external energy meter By plotting the outputs of both the internal and external energy meters at various operating voltages one can determine if the internal energy meter is correct If the calibration is found to off by more than an acceptable percentage then the internal energy meter needs be physically recalibrated The flow chart for energy calibration is shown in Fig 9 The START CALIBERATION process requires the outputs of both the laser and the external energy meter to be read the data averaged and standard deviation determined for Set HV and step increment Set data averaging of Laser Energy Start Calibration Set HV automatically tecerkun Read Ein and Eex Take Std dev and mean Compare is Mo HV max 7 Ves Save in Excel file Plot Eex Ein vs HV W
4. All related to step wise explanation confirmation of the manual part of the gas user messages fill operation are displayed to the user when this VI is run MODULES FOR EXCIMER LASER sub VI modules like Port Initialization Gas Fill operation Monitor and set There are four parameter and Energy calibration for excimer laser which have been designed under this module CONCLUSIONS GUI for port initialization setting and monitor all parameters of excimer laser gas fill operation and energy calibration for excimer laser are designed by serial interface using RS 232 DB 9 connector But all parameters of excimer laser are monitor and set with one second or two second delay Virtual instrument of Excimer laser and external energy meter is designed using LabVIEW software Real Time Data acquisition will be done in various file like doc pdf xls txt etc All laser operation will be done on internet in LabVIEW environment if all computers are connected ISBN 978 3 95450 124 3 49 WEPD23 Proceedings of PCaPAC2012 Kolkata India Figure 12 View of the plasma accelerator laboratory showing the ArF laser and the plasma accelerator chamber in LAN Automatic programming will be design for Laser operations and it will be change Laser operation will be become faster and safe than it operate manually Laser Laser VI Tree mer f Hatogen Read Write Data Command Logging Setting Step for Gas Fil
5. WEPD23 Proceedings of PCaPAC2012 Kolkata India DESIGN AND IMPLEMENTATION OF LABVIEW BASED GUI FOR REMOTE OPERATION AND CONTROL OF EXCIMER LASER FOR PLASMA WAKEFIELD ACCELERATION EXPERIMENT K K Mohandas K Mahavar R A V Kumar IPR Gandhinagar India S Joshi A Sharma Nirma University Ahmedabad India Abstract The paper describes the development of a GUI based control software for control operation maintenance and data logging of a Coherent CompexPro 102 Excimer Laser ArF 193 nm using LabView instrument control software INTRODUCTION The Coherent COMPexPro1l02 Excimer laser Fig 1 is an ArF gas based UV laser operating at a wavelength of 193 nm This laser uses Ar F2 Ne and He gases for its operation The laser can deliver a maximum energy of 200 mJ at 15 ns pulse width and capable of operating at a pulse repetition rate of 1 20 Hz The laser is normally controlled using a tethered control panel which has a cable length restriction of around 3 meters In order that the laser can be controlled and monitored remotely it is essential that a GUI based interface be developed The block diagram of system showing the gas feed system the I O system and the energy meters is shown in Fig 2 Currently the operation of the laser is carried out manually using the wired keypad The main motivation of the development of this GUI is for easier user convenience as well as for future use when the laser will be use
6. d to generate lithium photo ionized plasma for the plasma wakefield accelerator experiment system In the experiment the laser operation will be carried out remotely and the laser system will be integrated with the accelerator system operations via LabView instrument a n Figure 1 The Excimer laser system ISBN 978 3 95450 124 3 46 control software The GUI of the laser will be integrated with the GUI s of other components of the experiment Main Secondary walwe valve Comper Pro Excimer Laser intemal Energy Later Control i Figure 2 Schematic diagram of the excimer laser system showing the gas lines I O interfaces and energy calibration layout such as accelerator operation precision heater controls for the plasma chamber vacuum gas fill systems as well as data acquisition equipment thus providing a single window control of the whole experimental system Routine laser operation setting of parameters and running of laser maintenance operations like gas fill and energy calibration logging of laser parameters etc which are currently being carried out manually will be automated using the GUI This paper presents the development of the module for the excimer laser i e the required LabVIEW virtual instrument modules GUI interfaces and the required display screens for laser control parameter display gas fill operation as well as documentation logging of the operational parameters of the las
7. er system The paper also presents the development of a completely automated module for calibration of the internal energy meter of the excimer laser with a calibrated external laser energy meter Coherent FieldMax II This procedure is necessary as the performance and calibration of the internal energy meter which is used by the laser system to stabilize its laser output can vary over a period This one switch automated operation provides a linear fitted calibration of the internal energy meter with that of a pre calibrated commercial energy meter This procedure is Latest Trends in GUI Proceedings of PCaPAC2012 Kolkata India usually carried out after each gas fill to make sure that the health of the laser system is good Close MV1 to MV4 tightly Open SV1 to 5V4 Flushing GAS1 to GAS4 will be done Close MV2 to MV4 Flushing GAS4 will be done Purging Halogen will be done Close SV1 to SV4 Open MV1 to MV4 Read parameters and save Open V1 to SV4 at dbar New Fill will be done Figure 3 Flow chart for Gas Fill Operation The I O control of the laser is established via a standard RS 232 interface coupled to the PC through a RS 232 to USB interface LabVIEW tools like web publishing Tool structure palette string VISA palette have been used to design this graphical user interface The laser is designed to be controlled either from the control panel or from a remote PC but not from both a
8. ion 1s initiated from the Flush Line GUI all the gas lines will be flushed using helium gas and since Fluorine is a corrosive gas that line is flushed twice as a precautionary measure The image of the GUI for Flush Line is shown in Fig 4 Front Panel for New Fill and Purge Line This GUI assists in the gas fill procedure Once the NEWFILL operation is initiated the GUI will prompt the user to open or close appropriate gas valves MV 1 SV1 to MV4 SV4 and go through the process of first evacuating the gas lines and the laser cavity and then filling all the PORT INTIALIZATION MONITOR ALL PARAMETER GAS FILLOPERATION ENERGY CALIBRATION STOP HELP FLUSH LINE NEW FILL READ PARAMETER Figure 6 Front Panel for post gas fill parameters ISBN 978 3 95450 124 3 47 WEPD23 Monitor system Date and Time Set MODE by use Select Mode HVNGR HVPGR EGYNGR EGYPGR set parameters HV Energy Repetition rate Set Burst mode Burst pauses and Burst pulse Figure 7 Flow chart for monitor and set laser parameter Monitor system parameters And data logging required gases at appropriate pressures into the laser system Currently these gas valves are manually operated In future the whole operation could be fully automated if the manual valves are replaced by electrically controlled valves Once the gas fill is over the GUI will automatically flush the gas lines and purge the lines with inert
9. ith linear fit Figure 9 Flow chart for Energy Calibration Latest Trends in GUI Proceedings of PCaPAC2012 Kolkata India GUI FOR EXCIMER LASER PORT INTLALIZATION MOMTTOR ALL PARAMETER GAS FILLOPERATION ENERGY CALIBRATION STOP HELP Se s aS w 30 00 ieai am BE in Baers x En Energy Figure 10 Front Panel of Energy Calibration GUI various voltage levels The averaged data is plotted in the graph in situ After the process ends the data is saved in Excel form and finally plotted against laser high voltage as shown in Fig 10 The data points are then linearly fitted to obtain slopes which are then compared to determine 1f the calibration of the internal energy meter is within acceptable limits The internal statistical math modules of LabVIEW are used for this The logged data in Excel format is shown in Fig 11 Time HY Ea Linfit E Linfit Slope Slope SID E Fa Es Ea En H M 5 kV mJ mJ mJ mJ 11 13 52 24 103 13 104 18 109 43 108 85 14 65 14 53 TaS 11 15 50 25 123 2 118 83 113 64 133 39 14 65 14 53 8 15 11 17 32 26 137 42 133 48 129 25 137 92 14 65 14 53 7 20 11 19 46 27 155 79 148 12 151 34 152 45 14 65 14 53 7 45 11 21 52 28 168 85 162 77 163 17 166 99 14 65 14 53 6 43 11 23 43 29 181 06 177 42 178 28 181 52 14 65 14 53 7 97 11 25 52 30 193 73 192 07 191 75 196 06 14 65 14 53 7 38 Figure 11 Data for energy calibration saved in excel file LABVIEW DRIVERS FOR EXCIMER LASER In
10. l H Multi Y Axes Graph Linear Fit Field Maxll Sub VI Laser Modules Error Messages Figure 13 The V I tree for the Excimer laser Operations are easy to operate and understand by user Laser Data will be transferred for long distance using RS 232 to RS 485 converter ACKNOWLEDGMENTS The authors wish to thank Mr Yogesh Yeole and Mr Jinto Thomas for various help rendered with LabVIEW REFERENCES 1 John Park Steve Mackay and Edwin Wright Practical Data Communications for Instrumentation and Control Elsevier 2003 2 National Instruments LabVIEW 2010 software 3 Jovitha Jerome Virtual Instrumentation using LabVIEW PHI Learning Private Limited 2010 4 Hexin RS 485 to RS S232 interface converter Model 485 5 Coherent Interfacing manual for COMPEXpro RoHS ISBN 978 3 95450 124 3 50 6 User Manual for Coherent FieldMaxII P Laser Energy Meter 7 B la G Liptak Process Software and Digital Networking Instrument Engineer s Handbook 3 edition CRC press 2002 8 User Manual Coherent Energy Max Sensors Latest Trends in GUI
11. t the same time Field MAX II P energy meter with an energy sensor optimized and calibrated for use with 193 nm UV laser is used for external energy measurement The UV sensor incorporates a DUV quartz diffuser for increased coating damage resistance The energy meter has USB I O connectivity and hence could be seamlessly integrated into the laser GUI MODULE FOR GAS FILL OPERATION Excimer Laser uses a mixture of various gases depending on the wavelength of operation of the laser The 193 nm operation of the laser uses he Ne Ar and F gases in various proportions which are decided by the laser system at the time of gas filling operation The gas PORT EVTLALIZATION MONITOR ALL PARAMETER GAS FILLOPERAMION ENERGY CALIBRATION STOP MELP FLUSH LIME EN FIL AD PARAMETER nepa a pa L Figure 4 Front Panel for Flushing gas lines Latest Trends in GUI WEPD23 Se EE ara ee a PRESSURE mbar Figure 5 Front Panel for New fill and Purge line fills have to be carried out periodically so as to maintain the laser at its operating energy The flow chart of the gas filling process based on which the GUI has been designed is shown in Fig 3 In this GUI gas flushing new fill purge gas line and data logging are automatically carried out Front Panel for Flushing gas Lines Gas flushing is an essential step to clear the gas lines of all impurities before the actual gas fill operation is initiated When this operat
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