Faculty of Physics, University of Belgrade General meeting 19 th of August, ToF-LR HV Upgrade Jovan Puzović, Faculty of Physics, Belgrade

Faculty of Physics, University of Belgrade General meeting, Page 2 out of 24 Jovan Puzović, Belgrade SHINE team Introduction In the last 3 years we observe increasing failing rate of HV CAEN distributor units due to aging (4-5 per year) We already inherited a lot of bad distributors from previous period Long term stability od ToF HV system cannot be achieve with existing equipment The decision to refurbish the system has made

Faculty of Physics, University of Belgrade General meeting, Page 3 out of 24 Jovan Puzović, Belgrade SHINE team Plan The idea is to replace the HV system in ToF-R with the new one and use working components as spare parts for ToF-L New (sophisticated) system from CAEN very expensive (~150 kEUR) Custom system, based on resistors divider, is much cheaper (~30kEUR) and enable needed functionality (HV reading, but not setting)

Faculty of Physics, University of Belgrade General meeting, Page 4 out of 24 Jovan Puzović, Belgrade SHINE team Advantages Electronics is not complicate, expecting robust design, stable work and lower failing rate Price is ~5 times less comparing to new CAEN system needed to replace the old one High voltage level can be monitored by control logic in crate by using already existed cables and software in PC located in counting room Without monitoring (losing of communication or power) can run in passive mode

Faculty of Physics, University of Belgrade General meeting, Page 5 out of 24 Jovan Puzović, Belgrade SHINE team Disadvantages Complicate procedure of setting and calibration Every distributor board is unique (according to HV specification for their set of channels) – not interchangeable HV can be monitored, but cannot be set without hardware changes on the board

Faculty of Physics, University of Belgrade General meeting, Page 6 out of 24 Jovan Puzović, Belgrade SHINE team ToF-LR HV upgrade All hardware finished!

Faculty of Physics, University of Belgrade General meeting, Page 7 out of 24 Jovan Puzović, Belgrade SHINE team ToF-R Caen Crates Crates 1 and 2 dismounted in January (near beam, easy to do), fully functionally Crates 3 and 4 dismounted now (far of the beam, bunch of cables, has to remove front panel of the crate and pull it backward, lot of jobs, time consuming… ) Crate 3 already malfunctioned, 3 slots didn’t work, those slots have been populated with custom made distributors in August 2012 Crate 4 slightly damaged during dismounting (one cable was broken), can be repaired (2-3 hours of work), but it is not urgent now 2 fully working crates spare

Faculty of Physics, University of Belgrade General meeting, Page 8 out of 24 Jovan Puzović, Belgrade SHINE team ToF-L Caen Crates Crate 3 on the left side was founded with one bad slot (9) This crate is far of the beam, on top, hard to dismount Hopefully, this slot was populated with Russian type distributor We decided not to touch it at the moment, and return Russian type distributor in broken slot

Faculty of Physics, University of Belgrade General meeting, Page 9 out of 24 Jovan Puzović, Belgrade SHINE team ToF-R Caen Distributors 14 distributors fully working, used to replace bad one on left side We repaired 14 more distributors (from both side) by bypassing HV relay, 7 of them used to replace bad one on the left side 7 fully functional distributors left as spare, plus 7 with one dead channel which also can be use as spare Still have 3 Russian type distributors, in the case of emergency In total: 21 distributors replaced on the left side In total: 7 (all channels) + 7 (one bad channel) + 3 (Russian type) spare distributors

Faculty of Physics, University of Belgrade General meeting, Page 10 out of 24 Jovan Puzović, Belgrade SHINE team ToF-R Caen Distributors 14 distributors fully working, used to replace bad one on left side We repaired 14 more distributors (from both side) by bypassing HV relay, 7 of them used to replace bad one on the left side 7 fully functional distributors left as spare, plus 7 with one dead channel which can be use also as spare Still have 3 Russian type distributors, in the case of emergency In total: 21 distributors replaced on the left side In total: 7 (all channels) + 7 (one bad channel) + 3 (Russian type) spare distributors

Faculty of Physics, University of Belgrade General meeting, Page 11 out of 24 Jovan Puzović, Belgrade SHINE team ToF-R New Distributors All 4 crates installed in the pit All distributors installed Communication with PC in counting room established Monitoring program finished All HV readout channels calibrated We have problems with 4 HV channels (out of 891), not at nominal voltage, resistors have to be check

Faculty of Physics, University of Belgrade General meeting, Page 12 out of 24 Jovan Puzović, Belgrade SHINE team Summary Left wallRight wall End of BeBe run Now End of BeBe run Now Bad distributors22 1 (1 channel) 11- Bad channels (undervoltage) problematic

Faculty of Physics, University of Belgrade General meeting, Page 13 out of 24 Jovan Puzović, Belgrade SHINE team Bad pixels Tomorrow we start examination of problematic cassette and pixels on the left side We hope that we can open 5-6 most problematic cassette and find the reason why some pixels are dead If they are broken, we try to replace them

Faculty of Physics, University of Belgrade General meeting, Page 14 out of 24 Jovan Puzović, Belgrade SHINE team Thank you!