High Voltage system for the Double Chooz experiment

Transcription

1 High Voltage system for the Double Chooz experiment Fumitaka Sato Junpei Maeda Takayuki Sumiyoshi Kento Tsukagoshi (Tokyo Metropolitan University) for the Double Chooz collaboration 1

2 7m Double Chooz detector 7m Globe Box Outer veto Cosmic muon identify and veto [plastic scintillator strip] Inner detector (ID) ν-target Generate neutrino signal [Gd doped(1g/l) liquid scintillator(10.3m 3 )] γ-catcher Capture escaping γ-ray from target region [Liquid scintillator without Gd doping(22.3m 3 )] Buffer Reduce fast neutron and accidental γ-ray [Mineral oil (110m 3 ) + 10 PMT 390] Inner veto (IV) Back ground identify and veto [Liquid scintillator (90m 3 ) + 8 PMT 78] 2

3 Readout system Photomultiplier tubes ID : 390 PMTs (R7081MOD) IV : 78 PMTs (R1408) HV-Splitter (by CIEMAT) Frontend Electronics Signal Signal HV HV HV-Supply SY1527LC & A1535P (by CAEN) Trigger & Clock ν-fadc μ-fadc Trigger & clock ν-daq 1 P.E. pulse 3

4 High Voltage system Hardware properties Calibration system Software Data quality monitoring system 4

5 HV crate Front view Back view SY1527LC crate 2 crates/ one detector 16 slots / crate size : 19-inch 8U weight : 24 no module operating temperature : 0~40 CPU and original OS are in itself Ethernet port interface is implemented be able to operate remotely (TCP/IP) 5

6 HV module A1535P module 24 individual channels / module can be replaced channel by channel Max voltage : 3500V Max output current : 3mA Voltage set/monitor resolution : 0.5V Current set/monitor resolution : 0.5μA Radial 52-pin connector Channel chip Front view Side view 6

7 Splitter circuit for the PMT Patch panel splitter circuit 470kΩ 12nF 470kΩ 12nF frontend 6.8nF 10kΩ Single cable is used to HV supply and signal output. Reduce cost and the volume for cables. Need the splitter circuit which separates signals from high voltage (by CIEMAT). High voltage noise would contaminate to signals from PMT?!"#$%&$"''()*+,-$.'/'01'2$3--4 7

8 Splitter circuit for the PMT Patch panel splitter circuit 470kΩ 12nF Dummy load 470kΩ 12nF 6.8nF input ~1 mvpp 12MΩ!"#$%&$"''()*+,-$.'/'01'2$3--4 Checked the noise from high voltage by oscilloscope. Noise from High Voltage can be reduced enough by splitter circuit. Noise observed oscilloscope is about 1 mvpp. 8

9 High voltage module calibration 9

10 HV calibration system HV output/monitor value is calibrated by a special calibration module. Calibration module HV module T1535P developed by CAEN. 24 digital voltmeters are placed on the calibration module to calibrate all channels, instead of HV chip. Calibration module reads the output voltage and send back to HV crate. Vset Vmon Vout HV module HV crate (SY1527LC) Vout read calibrate Calib module digital voltmeter Vset : voltage which we want to put Vmon : voltage monitored by HV modules Vout : Actual voltage applied 10

11 HV calibration result before calibration after calibration } 100 (%) set V mon - V set PMTs V mon - V set -V set ) / V mon {(V Module/Channel {(V -V set ) / V } 100 (%) mon set Module dependency reasonably disappeared after calibration. Vmon are almost same value as Vset (within ~0.05%) 11

12 HV calibration result before calibration after calibration } 100 (%) set -V set ) / V mea {(V V mea - V set Module/Channel PMTs V mea - V set {(V -V set ) / V } 100 (%) mea set Checked the output value by digital voltmeter (= Vmea). Vmea( Vout ) has narrow distribution after the calibration. still biased to positive side a little 12

13 High voltage software 13

14 HV software Control GUI TCP/IP TCP/IP TCP/IP HV server Online Monitor Shifter G5/O3,! database (MySQL) -Setting table -Monitor table -Voltage -Current TCP/IP Monitor server TCP/IP Laboratory Control room 14

15 HV control On/Off Set Value directly from database Store the status to database Check the status 15

16 HV Online monitor Detector map HV value distribution 16

17 Data quality monitoring 17

18 HV status monitoring Offline data quality monitoring system is developed. Database for HV and run information is used for this monitoring system. Check the HV data quality. run-wise : Check HV status in each run or time range. HV-wise : Check HV status in HV channel. The preparation of WEB interface is ongoing. Example plots Maximum difference from RMS of voltage in a run. the set value in the detector 18

19 HV status monitoring 19

20 HV status monitoring Voltage deviation vs Time max deviation during time range Check the stability of HV for about two month. High voltage deviation is within ~0.1% for about two month. ~0.8% gain deviation of PMT. 20

21 Summary High Voltage system for 468 PMTs of the Double Chooz detector was constructed. Splitter circuit was developed and succeeded to reduce noise from HV. Control and monitoring software is working properly. HV calibration was done and succeeded to reduce module dependency. Data quality monitoring system is also developed. HV was very stable in two month. All the high voltage system for the Double Chooz experiment is working properly and very stable. 21