Status of the PSD upgrade - Problems with PSD in Be runs - Modification of cooling system - New temperature control - Upgrade of HV control system - MAPD gain monitoring system -PSD readout upgrade -Nearest plans F.Guber & A.Ivashkin, (INR, Moscow) NA61/SHINE Collaboration meeting, Wroclaw, Poland, October ,

Problems with the PSD in Be-runs 1.No PSD MAPDs and electronics cooling in 2011 Be run; Be runs - the air flow from underground for cooling; Not effective cooling system! 2.The temperature sensors in modules have been not working properly (strange long term behavior of T-sensors). Only 3 normal t-sensors have been used in the last 2013 Be run. 3. HV control system didnt not readout MAPD voltages (minimum functionality). 4. No monitoring system for the MAPD gains (minimum functionality). 5. The rise time of PSD trigger signal is slow – problem with the time-amplitude walk and signal delay in trigger box. 6. Electronics noises are rather small but comparable with MIPs signal. It makes problem with muon calibration. E beam =30AGeV Energy in PSD Temperature MAPD gain ~4 %/ 0 C 2

Strategy of the PSD upgrade in New cooling system with air chiller. 2.New temperature control system. 3. New HV control (readout of real voltages). 4. Monitoring system for the MAPD gains (LED stabilized source). 5. New PSD trigger signal after fast amplifiers. 6. New readout system (fast amplifiers+ DRS4). 7. Compatibility with existing readout. Present status of the rare side of the PSD 3

60 layers Al plate HV distributor PCB board End cover Plastic tube Lead-scinti, WLS-fibers with 11 optcal 11 SiMs board with with electronics with air inlet from air ~120 cm connectors T sensor (Power 0.5W) distributor box 100 – 160 mm Could be ajust in this range Temperature in this area should be ~20 ◦ ±1 ◦ New structure of the PSD electronics and temperature control system Chiller/heater (t~16-20 ○ ) Air distributor box Pumped air Valve on each module air tube 4

Heat sources around photodetectors In PSD module (simulation results - G. Camplone, Enrico Da Riva (CERN)) Main source of heat is FEE !? Effect of surrounding air temperature is negligible? The total heat transferred from the outer surfaces with the room temperature (T = 28 degrees) is highly inferior to the power which dissipate from the PCB board (0.5 W) 5

Temperature distribution in the PSD module (simulation results) Inlet air 12 0 C V=1.26 m/c Air velocity Surrounding air T=28 0 C Air flow does not help? Needs experimental tests! T MAPD ~26 0 C The final concept of the PSD cooling is not fixed yet! 6

New slow control system. Originally developed for COMPASS ECAL Can control up to 127 devices (modules). Can control the gain monitoring system too (next slide). Connection with external computer: USB-2.0 or RS-232. Internal bus: RS485 Maximum length of bus cables: 50 m Controller for SC New HV distribution system Extremely low power consumption. HV stability – 0.01%. One external power supply ~12 V. Permanent check of correct HV values within given HV gate - There is feedback to HV values! Already tested for a few years! ! Developer - HVSys Co., Dubna. It constructed the slow control for COMPASS EM calorimeter with MAPD readout. 7

MAPDs gain monitoring system Light amplitude is controlled by PIN-diode inside with very low temperature dependence. Control of MAPD gain at <1% level 1 device in one module. Based on stabilized LED source. 8

The PSD trigger signal 60 ns 300 ns MAPD signal M~5x10 4 integrated signal M~10 7 ADC signal Be runs: the PSD trigger signal comes after integrators with rise time ~60 ns: rather slow and large time- amplitude walk. Needs careful adjustment for each beam energy and each beam ion. In :…. trigger signal after MAPD – fast signal, no problem with time walk and delay. Fast trigger requires new amplifiers and new adders. Matching with DRS4 readout is needed. Additional (service) PCB to be compatible with old readout is required. 9

First prototype of FEE and slow control system is ready MAPDs Al-plate+ T-sensor LED source HV channels 10 Analog signals +trigger (adder) SC connector PCB with amplifiers and adder Test of prototype is ongoing now 10

PSD upgrade plan: -July – September (Moscow) Production of FEE prototype and test at test-bench. -October-November (CERN) Assembling and test of new electronics for one module at CERN -November – February 2014 (Moscow) Mass production of new PSD electronics. -March – April 2014 (CERN) Installation and test of the PSD electronics and temperature control system at NA61. Summer 2014 –the PSD test on cosmic October 2014 – test/calibration of the PSD with proton (better with muon beam!) Estimated beam time ~ 3-4 days. Important question – upgrade of the PSD platform control system should be ready before October

Thank YOU 12