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HBD Update:DC Meeting June 2006
Thomas K Hemmickfor the HBD Crew…
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Overview of HBD Progress:• HBD Prototype Tests:
– Excellent Experience; many lessons learned:• Install; Cabling; HV; LV; Noise;
Gas QA; Gain; Elect; DAQ; LVL-2;Offline;
– One Mystery in Data:• MIP apparently seen (Forward Bias).• Electrons give larger signals (great).• All Signals too low…Factor of 6 Mystery.
– Learning the surprises now is the PURPOSE of the test…
• HBD Construction:– HBD #1 nearly complete…Ship next week.– Glove Box installed & Running at Stony Brook.
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Quick Comments:• Installation: smooth…but detector should have “handles”
instead of gas pipes for lifting.• Cabling: Final cabling plans excellent. (D. Lynch)• HV: Continuously at full voltage…never tripped.• LV: Fool-proof…low noise means good grounds.• Noise: pedestal sigma < 0.5 photo-electrons.• Gas QA: Plumbing perfect; detector is ONLY source of
contamination…prototype leaks/outgasses some:– 20-25 ppm water, 15-20 ppm oxygen; ONLY 3-4 p.e. loss.
• Gain: 55Fe source shows published gain.• Electronics: Works through Full DAQ. Maybe fastest turn on
of new system in PHENIX history??– A few channels died (while cabling?). Must investigate.
• DAQ: Reliable. System occasionally needed feeds.• LVL-2: SUPERB!! The LVL-2 stream = high purity electrons.• Offline: HBD data smoothly included in CNT files…
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50mV 100mV 250mV
500mV 1000mV 1500mV
Calibration:
• Calibration uses test pulser input of pre-amps read through full electronics chain.
• Each channel gets gain curve.
• Online determination shows 0.1 fC/ch.
• Exactly the same as design value.
PadId1 PadId4
PadId5 PadId8
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Gain of Detector (Hutch Test):
• 55Fe source (6 keV X-rays, 109-e’s). Clear peak.• Absolute gain can be determined by comparing the
signal from pulser (known charge) to 55Fe.• Gain = 1 x 104…exactly consistent with publication.• Same pulser that propagated through full chain.
Pad 13 Fe55 Pulse Height Distribution(D V =495 V, DG=+0.5kV/cm )
0
50
100
150
200
250
0 -0.1 -0.2 -0.3 -0.4 -0.5 -0.6 -0.7Pulse Height [V]
Co
un
ts
430mVGain=1x104
Pulser
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Hadrons and Electrons in Forward Bias
• Forward bias allows hadrons to make reference signal.
• MIP apparently seen…electrons give bigger signal.• Factor-of-6 Mystery: Calibration says MIP peak
should be channel 600 instead of channel 90.
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Row-Column Correlation
• “Rows” in phi, “Columns” in Zed.• Offline determines predicted
location of track.• Clear correlation of track
projection with struck pad.
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Forward-1X Gain
Reverse-2X GainForward-2X Gain
Reverse-1X Gain
Electron Hit Finding• Electrons are
produced in the collision and in the HBD back plane.
• Should be ~2X as many from behind HBS as in front.
• In forward and reverse mode electron efficiency roughly right and independent of gain.
Forward
Reverse
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HBD In Beam Tests• Extremely valuable experience.• Detector seems operational and responds
differently to hadrons & electrons.• Need to complete all data analysis for N0.• Factor-of-6 Mystery might be most
important discovery (why we did this now).• Request for getting HBD “out”:
– Return detector to floor (dead turtle position).– Restore to hutch tests.– Main Electronics Chi.
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Main HBD
• 10 days to finish 1st vessel after PCB.
• 2nd PCB shipping to WIS now.
• First Vessel Ships Middle of Next Week.• Second Vessel Ships End of June.
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Glove Box is here and installed.
• 0.6 ppm water!!• Equipping unit for production now.• Dry run next week…production after…• <1 month per HBD (factor of 2 contingency)
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Summary• Need to finish analysis of all data.• Need to understand Factor-of-6.• On track for vessel delivery 1st August
(tight but can be done).• Pre-amp board needs to be farmed out.• FEM Electronics need 3 months after final
design (3 weeks from now following post-mortem of dead channels)– End of September…– Not a delay of vessel installation…
• “May you live in interesting times”.--RFK Chinese Curse(??)
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