1. + 2009 Summer Updates- Summer Student Report Emine Altuntas Stephen Fee Supervisors: Mar Capeans, Ivan Glushkov, Roberto Guida Gamma Irradiation Facility (GIF) RPC Gas System

2. + GIF Humidity and Temperature Control System – The Tent Construction and operation of the tent Purpose of tent: - Controlled environment for temperature and humidity for the chambers - Achieved by temperature and humidity control devices - Conditions monitored by measurement devices in the tent - Tent is now sealed and operational at the GIF! Current Status Inside The GIF 2 m 2.5 m

3. + GIF Humidity and Temperature Control System – The Tent Current Status Inside The Tent

4. + GIF Irradiation positioning RPC Tent ATLAS Tent Old position Safety zone ATLAS Tent Desired position

5. + GIF Humidity and Temperature Control System – The Tent - Current conditions in tent are approximately 40 %RH to 50 %RH, temperature of 20 °C - Maintained at this state by the dehumidifier and air conditioning Air conditioner - Control of Temperature and Dehumidification (but not to setpoint) -Dehumidifier - Dehumidification (not to setpoint) -Both are protected by lead shielding - Limitations: the devices cannot be controlled remotely, no set point for humidity

6. + GIF Humidity and Temperature Control System – The Tent Measurement Devices in Tent Hygrometer Weather Station - Hygrometer gives measurement of temperature and humidity in the tent - No need to protect from radiation – mechanical device - Needs regular checks for ink and paper changing -Weather station records live data to a PC in the GIF - This data can be accessed remotely at any time Conclusion: We now have a system to control and measure the temperature and humidity for the chambers

7. + Checklist for the GIF - RPC Gas System The RPC gas system checklist is completed every day. A hard copy of each day’s checklist as well as an excel file record is kept for future data analysis. In addition to the points shown here the supply mixture peak areas and the MS vacuum quality concentration units are recorded. The supply mixture peak area and concentration values can be found at https://twiki.cern.ch/twiki/bin/view/LHCgas/G CMS. https://twiki.cern.ch/twiki/bin/view/LHCgas/G CMS With the transition to the closed loop configuration new check points need to be added. A log file is added to each day’s GC-MS analysis folder at the GIF. Thus data collection process can be followed more accurately in the future. Closed loop Open mode

8. + Checklist for the GIF - RPC Gas System Right now the gas mixture is analyzed with the MS-GC every day at 6 different points: Supply gas mixture to the open loop Return gas mixture from the open loop After MS5A purifier in the closed loop After NiAl purifier in the closed loop After R11 in the closed loop The return mixture after all the purifiers in the closed loop

9. + - Originally in the gas system, flow in ≠ flow out. More than 50% of gas was missing - Does not represent closed loop conditions, and costs money - Leaks suspected in the system GIF Gas System - Leak Hunt

10. + Leak detection - Firstly general gas detector and a Freon gas detector were used on the whole system - These devices identified many leaks in the system - Connection points, Teflon tape - Solution: Tightening of connections, replace tape, assistance from technicians - Still many leaks remained… GIF Gas System - Leak Hunt

11. + Helium Leak Detector Procedure: -Run the system with 5% Hydrogen in nitrogen - Hydrogen will be released at high rate through the smallest leaks (small molecular size) - The detector was found to be very specific and accurate in the leak detection - Leaks were then fixed, the system is now running with no major leaks Conclusion: The helium leak detector is much more specific and faster than other methods and should be used for future leak detection GIF Gas System - Leak Hunt

12. + Purifiers and Regeneration The Purifiers Tested At the GIF The open loop purifiers Molecular Sieve 3A, 4A, 5A NiAl, NiSi, R11, R12, SiGel 2 l cartridges The closed loop purifiers Cartridge 1 (big one): 90 % MS4A + 10% MS5A Cartridge 2 (small one): R11 Cartridge 3 (small one): NiAl The concentration levels of H2O and O2 are analyzed in every data collection. Over time the sieves of each purifier become clogged. And purifiers do not perform at the desired level. The increase in the tendencies of H2O and O2 levels indicate the need for regeneration.

13. + Purifiers and Regeneration Regeneration Process The heat controller Gas System Rack Regenerator Gas flow control rack

14. + Purifiers and Regeneration Regeneration Process Inside the toaster the purifiers have been heated to 230 C Each purifier is flushed with a standardized mixture of argon and 5% hydrogen. In the case of MS4A and MS5A, as the purifier is heated the opening of the sieves increase. As the purifier is flushed with gas, the molecules stuck between the sieves are removed. Each purifier is regenerated for fourteen hours. After the heat is turned down each purifier is flushed with the standardized gas mixture for another four hours.

15. + Purifiers Table 4A5AR11Nickel Aluminium Nominal Absoprtion capacity 21% w/w water 22 % w/w water45-97 g/kg waterNo data 0% oxygen 4l O2 per 1 kg catalyst 17l O2 per 1l catalyst Amount in GIF set-up (g)240.3224.58251.9274.6 Expected lifetime for nomimal gas flow in GIF set-up (h) Conditioning time (measured for each cartridge individually) [min] Component of the RPC nominal gas mixture abosorbed by the purifier Conditioning time of the whole set of absorbers together [min]

16. + GIF - RPC Gas System Checklist Data Analysis Purpose – To acquire comprehensive and comparative graphs of the recorded values over time for further analysis Method: The ISR RPC gas system checklist code is taken as the start point. With the updates the current code; Reads data records from the checklist excel file The output graph files are recorded in the analysis folder Each data entry is assigned to representative holder Min and max finding for constructing the graphs

17. + GIF - RPC Gas System Checklist Data Analysis With the updates the current code; A comparative graph of active zone & open loop mixture temperature and RH values A graph displaying the change in the current over time in each channel The percentage deviation from the average current in each channel Fresh gas mixture composition

18. + Air Calibration Report Air calibration required to assist on ongoing gas measurements at the GIF Aim: To achieve calibration for main components of air, plus additional components detected Procedure: Analyse a known concentration of component using the GC-MS device Result: The peak area can then be equated to the known concentration

19. + Air Calibration Report Oxygen Calibration Achieved by analysing atmospheric air (21 %v/v oxygen) and bottle of 50 ppm oxygen in argon Oxygen presents in module C (molecular sieve) of the GC (cannot separate air in modules A or B) Oxygen could not be isolated from the 50 ppm analysis: Argon and oxygen peaks present at the same time The calibration is thus based on analysis of air only

20. + Air Calibration Report Achieved by analysing atmospheric air, 78 %v/v Nitrogen Nitrogen presents in module C (molecular sieve) of the GC (cannot separate air in modules A or B) Achieved by analysing atmospheric air CO2 presents in module B (PPU) of the GC The concentration of CO2 in atmospheric air is taken to be 0.0383 % v/v for the calibration calculations. Nitrogen CalibrationCarbon Dioxide Calibration

21. + Air Calibration Report Water Calibration Achieved by analysing atmospheric air and bottle of 110 ppm water in argon Water presents in module B (PPU) of the GC Water peak from air Water peak from 110 ppm analysis Ratio of peak area to concentration for 110 ppm analysis = 10.07  The two results are not in agreement.  Reason : The air analysis is not guaranteed to be accurate due to the possibility of change in the absolute humidity of the sample. This is because of the discrepancy between atmospheric pressure and GC carrier gas pressure.  Thus the calibration is based on 110ppm water in argon analysis Ratio of peak area to concentration for air analysis = 1.35

22. + Air Calibration Report Argon Calibration Achieved by analysing bottle of (almost 100%) argon Argon presents in modules A & B of the GC

23. + Air Calibration Report Conclusions Calibration now available for the components of air: ComponentModule Appearing inTime of peak value (s)Peak area corresponding to 1% v/v (µVs) O2O2 MS5A4030987 N2N2 MS5A43.630712 CO 2 PPlotU23.346823 H2OPPlotU80.913541/100673 Ar OV1/ PPlotU 17.314187/30644

24. + Looking Ahead The existing checklist needs to updated with the addition of closed loop parameter readings Such as, the closed loop temperature and humidity values It is necessary to complete and test the ROOT checklist analysis code For purifiers, regeneration is essential to be conducted without stopping the system and interrupting the data collection Thus a similar setup to the one existing at LHC may be considered – of course taking into account time scale of this update and costs The F - production rate to be studied Hanna double channel analysis station MS-GC software problems The temperature and humidity control to be established for a long time in the tent – no short term fluctuations recording of values

25. + Acknowledgements Experience with C++ and ROOT Introduction to the gas systems The physics behind the RPC’s and RPC performance issues Other elements on RPC selection MS – GC analysis procedure Experience with MS – GC software integration techniques Lectures by leading physicists in the field Trips to the LHC experiments Thanks for all the support And assistance And discussions - explanations And fun conversations

26. + Personal Thoughts… The aims are challenging since: - Many impurities - Varying concentrations - Some concentrations very low = difficult to remove - Unknown effects on the chambers Good Luck!

27. + Acknowledgements and Thanks New experiences: - CERN - RPC - Working with radiation - Analysis methods and data analysis Outcomes: - Experience in international working environment - Further knowledge and experience in important areas - Looks great on my C.V.! Thanks and please continue!