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This document provides an update on the readiness of HBD (Hadron Blind Detector) for Run 10. It covers the refurbishment of HBD East, HV testing, CsI Quantum Efficiency, gas transmission monitoring, loss of light in tails of spectrum, front end readout and data volume, online monitoring, and data analysis.
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HBD Readiness for Run 10 Craig Woody BNL DC Meeting November 4, 2009
HBD East is Back and Completely Refurbished • HBD East was removed for • refurbishing on 8/26/09 • Refurbishing was completed in • record time (35 days!) • All problematic GEMs were either • repaired (washed) or replaced • All new CsI GEMs were installed • using the Rapid Method, which gives • minimal exposure inside the glove • box HBD East reinstalled on 10/1/09 C.Woody, DC Meeting, 11/4/09
Rapid Method Standard GEMs installed near laminar flow table (cleanest area inside tent) CsI coated GEMs installed inside glove box (minimize exposure time) Same method was used for HBD West which performed much better than the East in Run 9 C.Woody, DC Meeting, 11/4/09
HV Testing with CF4 (after HBD East was reinstalled in PHENIX IR) All modules (East + West) brought up to near operating voltage (DVGEM ~ 417 V) in CF4 No problems with any GEMs Only problems were with “Quad Trips” as experienced during the last run C.Woody, DC Meeting, 11/4/09
No Spares ! HBD HV System LeCroy 1450 HV System Relay Board trips mesh + GEM whenever either trip 1471N HV Module Added Trip Detection Circuit • Needs factory calibration + added trip detection • Finally got one replacement and seems to work • Second module (only spare) is on the way C.Woody, DC Meeting, 11/4/09
± 0.5 ± 0.2 CsI Quantum Efficiency QE of new photocathodes HBD West Npe measured 10/6/09 West 4.2 ± 0.1 p.e. East 4.6 ± 0.1 p.e. QE Intact! C.Woody, DC Meeting, 11/4/09
Gas Transmission Monitor Input ~ 0 ppm H2O and O2 East West Will run again with high flow rate ( ~ 4 lpm) Transmission monitor gives most reliable measure of O2 and H2O levels Output ~ 30 ppm H2O and < 5 ppm O2 C.Woody, DC Meeting, 11/4/09
Loss of Light in Tails of Spectrum • Saw a slow deterioration over time (~ 2 yrs) in the amount of transmitted light at • short (< 135 nm) and long (> 170 nm) wavelengths • Replaced all optics (mirrors and diffraction grating) and transmitted light is now • better than when the system was first delivered • Probable cause:Outgassing from movable mirror combined with extended • operation under vacuum (effect known by McPherson) • Solution: Replace optics and operate as a flow system with argon C.Woody, DC Meeting, 11/4/09
Front End Readout and Data Volume • Data volume was not a problem in Run 9 • 12 samples 6 words • Likely would be a problem in Run 10 with same format • New format • Sum of first two samples • Sum of last two samples • One selected sample in between • Code is written and partially tested • More testing to begin next week • 2 words ( x3 reduction) C.Woody, DC Meeting, 11/4/09
Online Monitoring Monitoring will remain essentially the same as in Run 9 • Monitor module gain run by run • Will add new plots of pad hit frequency to monitor occupancy Module pulse height Time sample distribution C.Woody, DC Meeting, 11/4/09
Data Analysis Monitoring detector performance • Need fast, realtime monitor of detector performance (Performance measure is Npe per single electron cluster; requires ~ 1000 open Dalitz pairs) • Requires central tracks as well as HBD information • Sample events (MB & peripheral) during data taking and run through complete production (1008 or RCF ?) (need ~ 200M peripheral + 600M minbias) • Requires reasonably good (although not final) calibration of all detectors, but we need this early and to keep up with it Offline data analysis • Normal production output (compact CNT) is too large to manage • Need to write out some intermediate size output file (something between compact CNT and n-tuple) • Should be a PHENIX object to maintain flexibility • Could be used by multiple interested parties (e.g., for any single or double electron analysis) • Would not be written out during production (safer, reduces complications) • Written to Working Group disks using Taxi after production finishes • Will be provided by HBD or other detector groups C.Woody, DC Meeting, 11/4/09
Summary • East and West detectors installed and operational • HV system working • All 1471Ns working and one spare on the way • Transmission monitor light transmission restored • New FEM code written and will be tested soon • Plan proposed for monitoring and dataanalysis I think we’re as ready as we can be at this stage… C.Woody, DC Meeting, 11/4/09