1. Active gas system status. S.Konovalov, K.Zhukov

2. Active gas system operation. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 2  Good design and high-quality assembling of the gas system.  Cooperation with the gas group.  Prevention (monitoring of the parameters, analysis of trends).  Spare parts. 1200 days of Gas system operation StartStopMonths 12/09/20082/12/20083.3 25/09/20097/12/201014 8/02/20117/12/201110 29/02/201214/02/201312,5 ≈40 Gas system was stopped. Datedays 27/08/2008Gas analyzer (CO 2 cell)2 18/12/2009Mixer rack (pressure gauge)0.5 5-18/02/2010Profibus problems1-2 25/03- 8/04/2010 Membrane rack (first stage pump)13.5 (12+1.5) 29/11/2010Gas analyzer (CO 2 cell)0.5 7/09/2011Membrane rack (first stage pump)<1 18 Efficiency ≈ 98.5 %

3. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 3 Plans Gas system upgrade. Some improvements for more safety, more reliability… Tests & regulations. Automatic operation of the gas system in auxiliary operational modes (Filling, Recuperation, CF 4 mixture, Ar mixture). Maintenance & reparations. First priority tasks for to address TRT leaks. TRT meeting Friday, 15 February 2013 “Gas system status”” https://indico.cern.ch/ conferenceDisplay. py?confId=236045 List of priorities on the last slide

4. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 4 First priority tasks for to address TRT leaks It is possible to stabilize leak in the most part of the leaking channels. For this it is needed to tune and keep with the big accuracy 2 parameters: gas flow in this channel and pressure in the TRT outlet (pump inlet pressure). leak OUT IN Pressur e OUT pressure is fixed. Input pressure is possible to change by changing of the gas flow. Leak in 1 place

5. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 5 First priority tasks for to address TRT leaks Gas flow regulation. Gas flow regulation in the existent gas manifolds is very rough. Design end production of the fine flow regulation valves is needed. Design of the new flow regulation valves is practically done. It is not needed to produce new distribution manifolds. old new

6. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 6 First priority tasks for to address TRT leaks Remote gas flow regulation. When leak opens it is developing during some time (sometimes a few hours, sometimes several days). Every time we need to adjust gas flow in the leaking channel we need to ask urgent access and spend 1-2 hours in the cavern. Design, some tests (including tests in the magnetic field) end production of the remote gas flow regulation is needed. This work is began (Sergei Katunin).

7. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 7 First priority tasks for to address TRT leaks Pump inlet pressure regulation. Requirement for the pressure regulation accuracy was ± 1 mbar. Real pressure regulation accuracy is even better ≈ 0.1 mbar. It is desirable to decrease fluctuations of the TRT out pressure even more in order to stabilize leak. 0.14 mbar Output pressure is oscillating.Input pressure is not constant. leak OUT IN Pressure

8. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 8 First priority tasks for to address TRT leaks Next steps: precise pressure sensor PID algorithm fine tuning pump input resistance regulation Replacement of the regulation valve. Before. Now. Regulation looks better. Pump input pressure fluctuations are at the same level ≈ 0.1 mbar. Valve opening position Valve opening set point

9. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 9 First priority tasks for to address TRT leaks Pump pressure was regulating relative to the pressure in USA15. Pressure in the cavern differs from the pressure in USA15. This difference is not constant. Sometimes ΔP≈0.2 mbar and even more. We have got differential pressure sensor. This gauge measures pressure difference between pump input and ID volume. It helps to stabilize TRT output pressure. More tests is needed with more precise pressure sensor in barrel distribution rack output. USA15 – UX15 PRESSURE DIFFERENCE FOR CIRCULATION PUMP OPERATION FEEDBACK UX15-YSA15 pressure difference 0.1 mbar

10. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 10 First priority tasks for to address TRT leaks Distribution Input pressure is not constant. It is proportional to the tank pressure. Problems with TRT leak forced us to change gas regulation algorithm. The original idea was to keep concentrations of the gas components with the best accuracy. Variation of the tank pressure could be quite big. New regulation algorithm is not perfect. Fine tuning is needed. It will require quite a long time. Gas regulation PID XeCO 2 O2O2 KpTiKpTiKpTi Minimum of the CO2 & O2 concentration fluctuations. 0.05400.1100.120 Before 20/08/2012 compromised. Better pressure regulation, concentration stabilities is still good 0.05100.1100.120 From 21/08/2012 to 21/11/2012 Minimum of the tank pressure fluctuations. 0.15 4 10 From 21/11/2012

11. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 11 First priority tasks for to address TRT leaks Xe mixture supply blowing out. Where was a few leaking channels [B43; C1; C4, C6] in which it was not possible to provide detector performance with minimum gas losses working in the loop. They were supplied with the gas from the gas system blowing out. Temporary set-up was assembled in USA15 and distribution part in UX-15. It is needed to design and produce permanent Xe mixture supply with gas flow, pressure readout, implementation into gas control and DCS, alarms…(practically one more distribution rack + some equipment in USA-15). Barrel M1, M2 St 1 St 2 St 3 St 4 leak OUT IN Pressur e breaks No leak CO2 in leak CO2 in Leak in 2 or more places leak Brake-through compromise

12. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 12 First priority tasks for to address TRT leaks Ar mixture supply blowing out. The decision to supply part of the TRT blocks with Ar based mixture could be taken. Gas system has to be ready for that. Temporary set-up was assembled. It consists of the mixer in SGX-1 and distribution part in UX-15. It is needed to design and produce permanent Ar mixture supply with gas flow, pressure readout, implementation into gas control and DCS, alarms…(practically another one distribution rack in the cavern + one more mixer in SGX-1). A R DISTRIBUTION A R MIXER

13. First priority tasks for to address TRT leaks Nitrogen removal/recuperation system. Envelop gas which comes to the gas system because if the leak consists some admixture of N 2. Membrane module is not able to remove this N 2. Some modifications in the recuperation system gave possibility to replace gas in the gas system and clean gas from N 2. This was 100% manual operation. Design and production of the nitrogen removal/recuperation system fully remote controlled is needed. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 13 RUN 2011 0.3÷0.42% RUN 2013 0.02%/day = 1 l/day N 2 concentration

14. First priority tasks for to address TRT leaks Nitrogen removal/recuperation system. Design and production of the nitrogen removal/recuperation system fully remote controlled is needed. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 14

15. First priority tasks for to address TRT leaks Nitrogen removal/recuperation system. S.Konovalov "Active gas system..."TRT Overview 15.02.2013 15 PRIORITIES.