Transcript ecalHV_Jun24

ECAL HV – C control system status
Outline
• Introduction
• Input from Yuri Gilitskiy / Mikhail Soldatov
• ECAL HV system test
Planning
•ECAL stability and CW noise tests
•ECAL HV control electronics modification for side A
LHCb CALO commissioning meeting 24.06.08
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Anatoli Konoplyannikov /ITEP/
ECAL HV – C control system status
Introduction
A few time ago it was found that for improvement the calorimeter HV control
system stability during maintenance time, it will be useful to modify a lit bit the
HV control boards. The possible technical solutions for the improvements were
foreseen by designers from the beginning, but to do this was decided after the
global system tests, if needed (there are spare pads and holes on the PCB for
placing additional components). Last three months the technical implementation
of the modification has been re-discussed by experts and improved.
Finally this question was discussed on our weekly commissioning meeting
3.06.08 and on dedicated meeting with Jacques. Then the dedicated tests of
the modified HV control board (as was recommended by Marie-Noelle) has
been done and modification of the HV control electronics for side C was done in
three days.
LHCb CALO commissioning meeting 24.06.08
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Anatoli Konoplyannikov /ITEP/
Input from Yuri / Mikhail:
 Current configuration definetely does not work
right
Possible solution is to protect the resettable fuse
from the “tremor” like:
 shunt resettable fuses with ordinary ones;
 put diode in parallel with the resettable fuses;
 put the resistor (~10 Ohm) in parallel with the resettable
fuses
 add filtering capacitance after the fuse (to the ground)
All these ideas can be tested in the lab
 Another option is to replace the fuse with resistor (?
Does it safe for the box in case of real troubles (from
Irina)? )
03 June 2008
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ECAL HV system study
After a fruitful meeting with Jacques, some tests of one ECAL HV board with
different configuration have been done by Tengiz, Yuri and me in the aim to
improve the system maintenance.
• The test confirmed the some oscillation behavior of the ECAL CW bases;
• In the same time the CW base maximum over current for one of 40 channels
group has been measured. Maximum current is less than 0.4 A;
• It seems, the reasonable solution to stabilize the HV system has been found:
 We decided to add in parallel with existing fuses the normal fast fuses of 0.5 A
(as it was foreseen in original design).
 During a few days this solution was tested and no any problems have been
observed. During the test all possible combinations of LV and MV powers
switching ON/OFF were tested.
 One natural power cut was happened in the test time, but no any fuses have
been destroyed.
 The solution with a 100 ohm current limiting resistor has been tested too. It
improves the system stability, but a noise test will be needed to validate this.
LHCb CALO commissioning meeting 16.06.08
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Anatoli Konoplyannikov /ITEP/
ECAL HV control board modification
Two normal (fast) fuses were added per each LV line in Wiener PS
parallel with existing. The fuses are easy replaceable,
due to the additional holes into a front-panel ~ 12 m
+- 7 V
(recommended by Yuri Guz)
~ 80 m
Agilent PS
PMT
group
Fuses
+80 V
+5.8 V
In
LV regulators
1
Current limiting
R = 0 or 100 W
CW
-5.8 V
CW
+80 V
2
CW
HV_LED_DAC board
8
~4m
Sketch of the LV and MV distribution of the XCAL HV system
with the last modifications.
LHCb CALO commissioning meeting 03.06.08
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Anatoli Konoplyannikov /ITEP/
ECAL HV – C control system status
Conclusion
•
16 ECAL HV control boards for side C have been modified, passed the QC
(in that time two of 128 opto-couplers were replaced ), mounted on the
detector and tested.
•
ECAL HV control electronics for side C is ready now for doing needed
commissioning tests.
•
The additional DAQ tests of the modified HV control electronics is foreseen in
the nearest future.
LHCb CALO commissioning meeting 24.06.08
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Anatoli Konoplyannikov /ITEP/