Transcript Integration of the HV, LED monitoring and radioactive

Design and integration of HV, LED monitoring and
calibration system for HCAL
Overview of the subsystems design
• High voltage system.
• LED monitoring system.
• Cs137 radioactive source calibration system.
Integration of the HV, LED monitoring and radioactive
source calibration systems on the HCAL detector
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Anatoli Konoplyannikov
High voltage system
Design and integration of HV, LED monitoring and
calibration system for HCAL
The Cockcroft-Walton (CW) base for
photomultipliers is used for LHCb
calorimeters. The PMT chosen for the
calorimeters is Hamamatsu photo-multiplier
R7899-20. The CW solution has the
following advantages over conventional
passive divider and transistor bases:
individual gain adjustment;
efficient operation at high rate;
low power dissipation;
low voltage cabling and connectors
reducing total cost.
HCAL CW base circuit diagram.
The HCAL high voltage (HV) system consists of:
* about 1500 CW bases, those soldered on the PMT’s leads and placed in each cell of HCAL,
* eight 216 – channels DAC boards for HV control voltage distribution,
* three power supply units (+80 V, +- 6 V). The DAC boards are placed around the detector
and the analogue HV control voltages are distributed to each base by a flat cable.
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Anatoli Konoplyannikov
High voltage system
Design and integration of HV, LED monitoring and
calibration system for HCAL
PMT ZL2595 Gain variation (R=500M connected to GND)
1,01
Gain deviation
1
0,99
G10^4
G10^5
G10^6
0,98
0,97
0,96
0,95
0
2
4
6
8
10
12
anode current (mkA)
Oscillogram of a CW – base voltage ripple
on dynode DY10
The gain deviation as function of the DC anode
current for three gains 10^4, 10^5, 10^6.
CW base main characteristics
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Anatoli Konoplyannikov
High voltage system
Design and integration of HV, LED monitoring and
calibration system for HCAL
The architecture of the subsystem is chosen taking
into account following considerations:
 * The DAC ICs should be kept in a region
with a lowest level of radiation.
 * The easy access for board exchange should
be foreseen.
* A cable length should be minimized in order to
avoid a ground loop voltage shift.
216 – channels DAC board block diagram
The board includes 200 channels of DAC
integrated circuit for HV control and 16 channels
for LED light intensity control. For readout of the
control voltages, the multiplexers and ADC IC are
used. An estimated power consumption is about
1.5 W per board and a board size is about 160*250
mm2.
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
LED monitoring design
calibration system for HCAL
The LED monitoring system is mainly
aimed at:
• a middle term monitoring of the PMT
gain stability,
• an ADC sample time calibration and
adjustment
Sketch of the optical part of the LED monitoring system
The LED monitoring system consists of four functional parts:
•optical mixer and light distribution fibers,
•LED driver with LED and PIN diode with amplifier for a LED light stability
monitoring. The PIN diode signal after amplification is sent to the LFB front-end
electronics board.
•light intensity control board with DACs ,
•LED triggering pulse distribution board.
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
LED monitoring design
calibration system for HCAL
The dedicated HCAL versions of the
LED driver and PIN diode amplifier
were developed. The main LED driver
features are:

controlled light intensity

edge sensitive triggering

overshot circuit allows to decrease
the trailing edge of a light flash

dimension of the printed board is
40*70 mm*mm
LED driver block diagram
mechanical design is optimised for
HCAL
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
LED monitoring design
calibration system for HCAL
Photo of the light mixer with LED driver and PIN diode
amplifier printed circuit boards
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
LED monitoring design
calibration system for HCAL
50 Gev pions
LED signal
Oscillograms of the 50 Gev pions signals and LED signals for clipped and non-clipped
cases. Signal clipped on 1.2 m coax with 22 Ohm termination
Comparison the signal shape for 50 GeV pions and LED signal
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
LED monitoring design
calibration system for HCAL
For LED trigger pulse
distribution a 64 – channels
dedicated board has to be
developed. It will be placed
in to the spare slot of the 9U
LFB crate. This crate is
connected to TTC and ECS
systems.
Synopsis of LED Trigger Board (LEDTB)
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
calibration system for HCAL
137Cs
radioactive source calibration system
System overview
The reliable and stable calibration method has been developed and tested with HCAL Prototype.
Its aim is to monitor the detector properties, like ageing of plastic and fibers, and give an absolute
reference for the cell calibration. The radioactive 137Cs gamma-source that has 30 years half-life
is used. Three sources encapsulated in the stainless steel pipe were obtained, with activities of 5,
8 and 10 mCi.
The HCAL calibration system incorporates the following parts:
•continuous 8 mm diameter stainless steel pipe that is fed through the middle of all scintillating
tiles and filled with a distilled water;
•a computer controlled hydraulic pump and valves that create a reversible water flow in the pipe
and therefore move the capsule with a radioactive source throughout the detector;
•an automated garage with a 5 cm thick lead wall, to safely keep the source between calibration
runs;
•integrated on-detector electronics to measure the PMT current when the source is moved from
cell to cell across the HCAL.
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
calibration system for HCAL
PMT anode current produced by radioactive
source is integrated by an electronic
integrator with a decay time of order of 2
msec. Readout board collects analog signal
from one module phototubes, digitizes them
and stores into a local memory (it takes 125
sec/module). Then the data are transferred
to a computer through CAN bus interface (it
takes about 4 msec). The readout continues
till the source run through the module.
Photo of the 8 – channels integrator and readout boards
Two or five 8 - channel integrator boards
(placed into the module) and 520 – channel
readout board (placed on the detector) have
been developed.
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
calibration system for HCAL
Garage for radioactive source storage
Photo of the rack with the hydraulic
and control electronic crates
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
calibration system for HCAL
PMT with CW base
Integration of the HV, LED monitoring
and radioactive source systems on the
HCAL detector.
Placement of the electronic boards and
connection with ECS
Photo of the internal cabling and CW base
integration into HCAL module
The electronic boards of mentioned systems will be
placed partially into the HCAL modules and around the
detector. There are two options for the board integration
on the detector. Main option is the electronics placement
on the top and bottom platforms. In this case one has
easy access to all boards, but the cable length of the
analog control signals is not minimal. Another option is
to distribute the boards on the side of detector. In this
case the cable length is minimal, but the access is less
convenient.
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
calibration system for HCAL
2 or 5 (16 or 40 channel HCAL
module) 8 contact coax connectors
for connection with Front-End crate
5 pin connector for PIN diodes
and LED triggering signals
2 of 10 pin connectors for CW
base and LED power supply
34 pin connector for Cs
calibration system
2 of 40 pin connectors for
HV control signals
HCAL module side panel with connectors
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
calibration system for HCAL
LFB rack with crates
LED triggering Board connected
to TTC and ECS
6U VME size crate for Cs source
monitoring, and control electronics
33 * 40 wire flat cable
The estimated crosssections of the cables
integrated on the HCAL
side are following:
• coax cables crosssection is about 120 *
120 mm2,
• flat cables crosssection is about 70 *
100 mm2.
850 coax cables of 3 mm
diameter
Two boards of HV and LED DAC control
voltage + one board of Integrators Readout
connected to ECS
Crate with hydraulic apparatus
Sketch of the electronic boards and crates
integration on the HCAL detector
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
calibration system for HCAL
System
Board description
Number of boards per half of HCAL
HV
216- channels DAC of the HV and LED control voltage
Power Supply:
+ 80 V (1 A)
+ 6 V (0.2 A)
- 6 V (0.2 A)
4
1
1
1
LED monitoring 9U VME 64 – channels LED triggering
Power Supply:
- 40 V (0.1 A)
+6 V (0.2 A)
- 6 V (7 A)
1
1
1
1
Cs calibration
and monitoring 520 – channels Integrators Readout Board
16-channels Capsule location sensor (SIN) monitoring board
Hydraulic control board
Garage control board
Power Supply:
~ 220 V (3 A)
+ 9 V (2 A)
+ 12 V (5 A)
- 12 V (3 A)
+ 6 V (2 A)
2
4
1
1
1
1
1
1
1
The list of the half HCAL electronic boards integrated outside of the detector
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Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and
calibration system for HCAL
Procedure of the PMTs assembly and cabling + needed manpower
• 1500 PMTs and CW base assembly – 3 man-weeks
• 1500 PMT + CW base test and Gain vs HV measurement – 6 man-weeks
• 44 sets of coax and flat cables preparation and installation inside HCAL – 8
man-weeks
• 1500 PMT + CW base installation into modules– 3 man-weeks
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Anatoli Konoplyannikov