Run period of summer 2012 Zoltán Fodor Wigner Research Centre for Physics, Hungarian Academy of Sciences

History of the period The original plan was deranged because of faults of our magnets. The original plan: Test beam: 18. - 27. June Hadron beam : 27. June – 21. August Be (Pb) beam : 22. August – 8. October The modified one: Started test beam at 18. June without magnet Hadron beam until 8. October Be (Pb) beam 3. - 17. December and 14. January – 11. February 2014

Goals: PSD calibration Test measurement for USNA61 This point was not effected by the magnet faults Test measurement for USNA61 Originally was planed together with PSD calibration, but it was not possible because of the VTX1 and VTX2 late readiness After the VTX1 accident, we used only the VTX2 reduced field, could be analyzed after the new field calculations Crosscheck of the p-+C total cross-section For the total cross-section the field not really needed but would be nice to have it. Some data was taken with the same field as p+C 120 GeV Some data was taken with K-+C systems High statistics for p+Pb collisions The data taking was started later and was interrupted by the magnet fault. After the magnet reparation it was continued

Magnet story(1) The electronics on the cryogenics system was obsolete, had to be changed. The CRIO group would be busy during LS1, therefore must be done in this year. VTX1 turned down after some operation in the preparation time: He pump seriously damaged, have to produce a new element inside pump. At that time the VTX2 was ready to use, but because it is similar system to avoid the serious damage they decided to do the same modification as on VTX1, must be warmed up the cryogenic part, do the modification and cool down again. Water valve was opened at not used part /very probably from the VTX2 accident in 1998/ and this tube was not connected to anywhere and was not closed, but the water was flushed the VTX2 electronics. ==> The magnet was ready to use only at 3 of July The S4 counter was not fixed strongly enough, moved at certain current and produced some spike in the monitor signal of the voltages drops on the coil, stopped ramp up the magnets and with fast discharge ramped down. The critical value was depend on the current in the VTX2. After modification of the software, we were gone over this problem for 10.July, until that time we measured with only 30 GeV field. /VTX1 and VTX2/

Magnet story(2) At 19.July Morning vacuum leak developed on the thermal screen in the downstairs bobbin of VTX1, the quench system forced to ramp down. At that time was known, one of the He circuit was broken. Increasing the pumping power we anticipated the too fast warm up producing condensations and ice in the VTPC hut. Warmed up the magnet with current in the coil Opened the vacuum chambers of the magnets Localized the leak, The first cast was not successful. Produced a new piece and welded it, checked with pressure and hit stress. Closed the vacuum chamber Started cool down with monitoring the He in the Vacuum At the first ramp up we get some high, but not critical quench signal, but the second times was very smooth. After the warm up the coils had taken his position, the mechanical movement induced the signals at first ramp up. The magnet was ready to use at 15. of July when started a long MD Restarted data taking p+Pb 158GeV

New piece

Additional measurements Used only VTX2 magnet we measured the p+C reaction at 120 GeV protons with the current in the VTX2 3500A. The limitations came from the limit of the voltage drops on the injections to the magnets at 4000A The signal of the S4 counter is dropped dramatically in the asymmetric field, with increased voltage and amplifier we could go until 3500 A. Measured the cross sections of the p-+C at 350 GeV beam for the cross check of the 2009 data. Using the opportunity we took some data with 350 GeV K- beam

p+Pb data 30 GeV field configuration Normal magnet settings 10. July – 19. July 21.September – 8. October

p+Pb second part MD and SPS problems After restart MD

11 Magnet date Run event Target in Target out PSD calibration 158 GeV p+Pb 30 GeV field 30.06 – 02.07 15717 15795 0.80M 0.02M 158 GeV field 10.07 – 19.07 15852 16057 4.13M 0.41M 120 GeV p+C Only VTX2 26.07 – 31.07 16063 16226 2.60M 0.27M 158 GeV h-+C 31.07 – 03.08 16229 16348 0.93M 0.35M 158 GeV K-+C 31.08 – 06.08 16349 16485 0.95M 0.19M 21.09 – 08.10 16542 17005 9.40M Krypton VTX1 25.06 - 28.06 15554 15634 4.26M Krypton GTPC 28.06 - 29.06 15669 15693 1.43M Krypton LMPD 27.06 – 28.06 15637 15666 1.59M

Problems during data taking At the beginning the DAQ crashed because of the PSD readout The TOF readout has instability, the connection between the VME and FASTBUS system, could be looks like running correctly but the BOSbank missing 1 TPC motherboard has to be changed Several low voltage power supply on TPC has trouble The temperature control of the TPC huts updated but not working as before /less stable, higher gradient as before/ The pressure regulator on the MTPC-R gas-system is leaking BPD1 lost signals , Oscar fixed it, there was a broken soldering on supply cart

Problems during data taking At the beginning the DAQ crashed because of the PSD readout The TOF readout has instability, the connection between the VME and FASTBUS system, could be looks like running correctly but the TOF BOSbank were missing 1 TPC motherboard has to be changed Several low voltage power supply on TPC has trouble The temperature control of the TPC huts updated but not working as before /less stable, higher gradient as before/ The pressure regulator on the MTPC-R gas-system is leaking BPD2 continue the features of last year, decreasing amplitude BPD1 lost signals , Oscar fixed it, there was a broken soldering on supply cart

To be improve One of the shifters must be experienced Proposition to have 2 kind of shifters: Shift leader and shifter The new shifters has to take a learning shift in advance It was decided 2 years ago!!!!! The expert has to be careful enough switching on/of voltages /when we switched of the TPC high voltage, we realized the strip voltage was not switched on./

The full system must be ready for 3.Dec. evening Preparation for Be run Installation of the quadrupole magnets between the S1 and S2, to be ready for usage if we could improve the beam quality /Ilias/ Gas start 25.Nov to be ready for 3.Dec /Antony/ Installation of Cherenkov counters Replacement of the BPD2 Installation of target holder, and alignment by geometers No action on the magnet One of the He flow control could not get the nominal current, but it would be enough for the low field, therefore decided not change it before the Be run /must be the full magnet warmed up and cool down/ The full system must be ready for 3.Dec. evening