Title: The TRD High Voltage Distribution Box MasterSlave System Progress Report
1The TRD High Voltage Distribution
BoxMaster/Slave System Progress Report
- Athens University
- A. Petridis
- M. Potirakis
- M. Tsilis
- M. Vassiliou
G.S.I 25-26/2/04
2- Requirements
- 1. H.V for the Drift Field (540 channels)
- About -2.1 K.V with an accuracy of about 2-5 V
(.1 to .2) - Allowed ripple less than 50mV peak to peak
- Stability .1 per 24 hours
- The allowed maximum current 7-10uA
- The accuracy of the current measurement at the
level of 2nA - 2. H.V for the Anode Wires (540 channels)
- About 1.7 K.V with an accuracy of about 1-2V
(.05 to .2) - Allowed ripple less than 50mV peak to peak
- Stability .1 per 24 hours
- The allowed maximum current 5-7uA
- Accuracy of the current measurement at the level
of 2nA
3- Solution
- Two Distribution Boxes (for better monitoring ,
save - space,
and cabling money?) - From a H.V, master system (ISEG,CAEN ), we apply
90 fixed - voltages to 90 cards. Each card contains 6
channels. - One card provides the appropriate power to a
single stack - of the TRD.
4- Trials
- Different approaches were investigated.
- e.g Swiching, low power dissipation but stability
problems. - Power supplies in series, carefull design
since all lines are in high - voltages.
- Proposed solution
- Shunt Regulator. Easy desigh, but relatively
high power dissipation - Lucky the Sanyo to reproduces the 2SC4370LS High
Voltage Low - current transistors .
- First measurement showed a good linear behavior.
5- Composition
- Each card contains
- One H.V input provides the ceiling Voltage
(1700/ -2100V) - Six High Voltage output channels, provide the
appropriate Detector - Voltage to within 1Volt accuracy. eg 1700 DV(in
a step of 1V) - One microcontroller of Avr(mega 8) drives
- 6 shunt regulators
- 2 DACs of 3 each ,
- Six single ADCs,
- 2 X 3 ADCs
- Six Swiches for swiching off the power of the
detector. - One input Reed Relay and
- One CanBus driver.
- 30 DC signal transformers .
6Each channel contains One Shunt regulator , one
12bit DAC, one 24Bit ADC plus one14Bit
ADC 5 DC signal transformers 11 One shunt
resistor of 0.01 accuracy and 3ppm/C
stability One voltage divider 1400 .05!
accuracy and 15ppm/C stability Low current low
noise Instrumentation amplifiers One comparator
and one error amplifiers One 2SC4730LS low
current transistor withstanding 2100 Volt. One
transistor switch. The resistors are accurate to
a level of .1
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8Isolated Shunt Regulators
9Non-Isolated Auxiliary Power Supply
10Two Auxiliary P/S for the isolated channels
11Current monitoring of first channel
12Another version for the current monitoring
13Voltage monitoring
14Microcontroller communication with the ADCs
15Digital Signal Drivers
16Microcontroller / RS232 Interface
17- Summary
- The prototype card is fully designed .
- Gerber files are ready.
- The size the PCB card is 16cm X 24cm
- The first two PCBs are going to be ready in
three weeks . - Tests will be started as soon as the PCBs are
ready. - Two different designs for current measurement is
to be tested. - Remarks
- Maximum current of the Master System.
(4mA/channel) - Input/Output connectors.
- Some space in the back plane of the rack for the
transformers. - Temperature variation in the hall.
-
18Setting up a HV system in PVSS for the TRD
19- PVSS V2.12 is running under Linux on a PC Pentium
IV 2.4 GHz - Control software for a HV system is under
development. - Continue the development under Linux ?
- Need for i. a Power Supply fully
equipped - ii. an IXXAT CAN
interface card - iii. a DIM / CAN
interface (Marc)