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HF Multianode PMT Upgrade
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Base Board Dy9, Dy10 Power
Modification
March 19, 2012
S. Los
HCAL/CMS, FNAL
March 19, 2012
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Board Modification
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• Modification to the Base
board includes two jumpers
(for Dy09, and Dy10):
– Allow to disconnect
resistive divider from
Dy09, and/or Dy10, to
avoid situation when
power supply should sink
current (reason for the
recently observed
“voltage spikes”)
– Bypass capacitors, and
booster voltages are
always connected to the
dynodes
Voltage distribution
to the PMT sockets
Resistive divider chain
March 19, 2012
Bypass capacitor chain
Dy09, Dy10 jumpers
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Base Board Luminosity Dependence
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• Base board divider standing current was increased a factor x10 with respect to the existing
situation
• We should test that this is enough to run at full SHLC luminosity, and not suffer from
luminosity-gain dependence (similar to what has Dick done for the prototype run without
two booster voltages)
– For a single particle hit (up to 300pC of maximum QIE10 signal) voltage drop on a 10nf
bypass capacitor is 30mV – only 0.05%of the operating voltage
– Dynode voltage recovery time is around 20ms (227 orbits of LHC beam, so we can only
be sensitive to the luminosity effects at that scale)
March 19, 2012
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Next Proto/Production
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Quotes for production run of 280 boards:
• $2700 - $4600
1. New prototypes of the HF Base board were ordered
last Friday, due at Fermilab in a week
2. Assembly of 12 boards will take another week
3. In the first days of April new boards should be
available for tests outside Fermilab
4. To be ready for spring 2013 I’d like to have an o.k.
for the final Base boards in September
5. Adapter boards, which did not cause any problems,
should be ordered a.s.a.p.
6. Cable retention boards should be prototyped, and
tested with the existing cable prototype
March 19, 2012
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