PHOTOMULTIPLIER HIGH VOLTAGE POWER SUPPLY SYSTEM FOR THE CMS FORWARD HADRON CALORIMETER

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PHOTOMULTIPLIER HIGH VOLTAGE POWER SUPPLY SYSTEM
FOR THE CMS FORWARD HADRON CALORIMETER

• Lubomir Dimitrov, Ivan Vankov
• Nuclear Electronics Laboratory, Institute for
  Nuclear Research and Nuclear Energy, BAS
• Serguei Sergeev
• Fermi National Laboratory, USA/Joint Institute
  for Nuclear Research, Dubna, Russia

I. Vankov NEC2005, Varna, Sept. 2005
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PMT HV PSS for HF

1. INTRODUCTION.
2. POWER SUPPLY SYSTEM
3. HV POWER SUPPLY MODULE
4. CRATE CONTROLLER MODULE AND MONITOR AND CONTROL
   UNIT
5. POWER SUPPLY SYSTEM SOFTWARE
6. BASIC TECHNICAL PARAMETERS
7. CONCLUSIONS

I. Vankov NEC2005, Varna, Sept. 2005
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PMT HV PSS for HF - INTRODUCTION 1

• Compact Muon Solenoid (CMS)

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PMT HV PSS for HF - INTRODUCTION 2
FORWARD HADRON CALORIMETER (HF)
Copper Block Cerenkov Detectors Embedded Quartz
Fibers
1728 Photomultiplyers (PMTs) Type Hamamatsu R7525
(8 dynodes)
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PMT HV PSS for HF - INTRODUCTION 3

• PROBLEMS
• CLASSIC SOLUTION INDIVIDUAL RESISTOR
  DIVIDERS GENERATE ALL PMT DYNODE VOLTAGES,
  BUT
• 1. NEED 1728 HIGH VOLTAGE CHANNELS and 1728
• 165 m long HV CABLES - VERY EXPENSIVE
• 2. LARGE SPACE FOR THE 1728 DIVIDERS
• 3. GREAT POWER LOSSES IN THE DIVIDERS
• PRODUCE MUCH HEAT

I. Vankov NEC2005, Varna, Sept. 2005
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PMT HV PSS for HF - INTRODUCTION 4
SPECIFIC SYSTEM STRUCTURE proposed by Dr.
David Winn from Fairfield University 72 READ OUT
BOXES (ROBOXES) 36 for HF1 and 36 for HF2 36
roboxes divided to 4 group of 9 corresponding
to the four HF quadrants IN EACH ROBOX 3
PRINTED CIRCUIT BOARDS (PCBs) WITH 8 PMTs HAVING
VERY SIMILAR GAIN/VOLTAGE
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PMT HV PSS for HF - INTRODUCTION 5
PRINTED CIRCUIT BOARD DIAGRAM
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PMT HV PSS for HF - INTRODUCTION 6
PRINTED CIRCUIT BOARD WITH 8 PMTs ONE RESISTOR
DIVIDER FOR THE FIRST 6 DYNODES WITH TOTAL
RESISTANCE ABOUT 20 Mohms MAX. CURRENT lt 50 uA
THREE SUPPLY VOLTAGES UK 2000 V UD7 800
V UD8 400 V RESULTS STABLE VOLTAGE TO
D7 AND D8 VERY LOW POWER LOSSES
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PMT HV PSS for HF - INTRODUCTION 6
ONE QUADRANT HV SYSTEM STRUCTURE
HV MODULE No 1
ROBOX No 1 3 PCs x 8 PMTs
9 HV cables L?15 m
1 HV cable L?150 m
PS1
U
UK,1
UK,1
UD7,1
Cable No 1
UD7,1
UD8,1
LG
UD8,1
Cable No 2
U
UK,2
UD7,2
LG
UD8,2
PS2
LG
UK,2
Cable No 9
U
UK,3
UD7,2
UD7,3
UD8,3
UD8,2
9 HV CHANNELS 1 MODULE 1 CLUSTER SUPPLIES 9
PCBs 3 GROUPS OF 72 PMTs WITH SIMILAR
PARAMETERS 1x9 HV WIRES 165 m CABLE 9x9 HV WIRES
15 m CABLES
LG
LG
PS3
ROBOX No 2
UK,3
UD7,3
UD8,3
ROBOX No 9
LG
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PMT HV PSS for HF CRATE DIAGRAM
4 HV POWER SUPPLY MODULES 3 HV CLUSTERS
A, B, C
CRATE CONTROLLER MODULE RS 485 CRATE
LOCAL BUS
MONITOR AND CONTROL UNIT 7 LEDs SYSTEM
STATUS 4 LIMITS Uklim, Ilim1, Ilim2, Ilim3
CRATE POWER SUPPLY 5 V, 8 V,
-8 V, 40 V
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PMT HV PSS for HF CRATE PHOTO
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PMT HV PSS for HF HV MODULE 1
A1, B1, C1 0 to 2000 V A2, B2, C2 0 to 800
V A3, B3, C3 0 to 400 V FLOATING OUTPUTS
ONE CHANNEL DAC HV SET VALUE
DC-DC CONVERTER 2 CMPs U and I
LOCAL CONTROL MUX12 bits ADC
INTERLOCK LED CONTROL
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PMT HV PSS for HF HV MODULE 2
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PMT HV PSS for HF CONTROL DISPLAY

• RS485 INTERFACE WITH HOST COMPUTER
• CRATE LOCAL BUS CUSTOM PROTOCOL
• 7 LEDS STATUS OF THE SYSTEM
• 4 POTENTIOMETERS U and I LIMIT VALUES
• A NEW FIRMWARE HAS BEEN DEVELOPED WHICH IS NOW
  CAPABLE TO CONTROL BOTH HCAL AND HF PS SYSTEM
  RECOGNIZING THE DIFFERENT TYPE OF MODULES BY
  THEIR UNIQUE ID NUMBER.

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PMT HV PSS for HF SOFTWARE
VERY SIMILAR TO THE HPD POWER SUPPLY SYSTEM MAIN
MONITOR WINDOW NINE CHANNELS STATUS LIMIT VALUES
VOLTAGE UP/DOWN RATES CRATE PS
VOLTAGES MODULE STATUS
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HV PSS for HF - PARAMETERS
PARAMETER CHANNELS A1,B1,C1 CHANNELS A2,B2,C2 CHANNELS A3,B3,C3
Max. operating voltage, V Voltage adjustment step, V Ramp rate, V/s Voltage ripple, mVp-p Voltage monitoring inaccuracy, Long term instability, Max. output current, mA Current monitoring inaccuracy, Special 2000 0.5 5 500 100 lt 0,1 lt 0,1 0,8 lt 1 Floating output 800 0.2 2 200 40 lt 0,1 lt 0,1 0,8 lt 1 Floating output 400 0.1 1 100 20 lt 0,1 lt 0,1 0,8 lt 1 Floating Output
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HV PSS for HF
CONCLUSIONS HV SYSTEM FOR HF PHOTODETECTORS OF 2
CRATES WITH 4 HV MODULES DESIGNED AND
PRODUCED LONG TERM TEST CONFIRMED
THE BASIC SYSTEM PARAMETERS AND ITS
RELIABILITY
I. Vankov NEC2005, Varna, Sept. 2005