Forward TOF Prototyping
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Forward TOF PrototypingRyan MitchellGlueX Collaboration MeetingNovember 2005
Purpose of the Forward TOFParticle ID:/K separation up to 1.8 GeV/c.
Level-1 Trigger:Fast forward charged track count.
Calorimetry:Tag hadronic showers in the forward calorimeter.
Forward TOFParticle ID:
70 ps time resolution
1% momentum and length resolutions
Current Design(and possible improvements)(Not to Scale)42 barsScintillators: 252 6 1.25cm Eljen-200 or BicronBeam Hole: 12 12 cm HolePhotomultiplier Tubes: XP2020Electronics: Alberta CFD JLab F1TDC fADCWould thicker bebetter?Is this the best we can do for...timing?fringe field? Need more experiencewith this (esp. range)...
Outline of Prototyping I:Finished/OngoingIHEP Test Beams 2001 to present-- < 80ps resolution is achievable with 200 6 1.25cm bars-- December 2005 tests will look at 250cm bars
IU Cosmic Ray Tests Spring 2004-- First measurements were made with a 250 6 1.25cm bar-- Find 88ps resolution in the center region (2 bars)
TRIUMF Beam Test Summer/Fall 2005-- Low energy //e beam used on two layers of scintillators-- Probing time resolution for a variety of dE/dx and all positions-- Discriminator performances
Outline of Prototyping II:3 Year PlanIU Cosmic Ray Tests 2006 to Spring 2007-- Another round of tests with the IU cosmic ray stand.-- 88ps is not sufficient; look at bar thickness.-- Try a variety of phototubes.-- Use Alberta CFD and commercial CFD and LED.
Hall-B Electron/Photon Tests (with LGD) Fall 2007 Run-- Take the final design to the Hall-B alcove test-- Scan 2 walls of 10 bars each (one full length; one half length).-- Correlate with the LGD and tagger.
Magnetic Field Tests (with LGD) 2008-- Make sure everything works in the fringe field.
2004 IU Cosmic Rays SummaryPMT: XP2020TDC:LeCroy 2228A (50ps least count)ADC:LeCroy 2249A and IU fADCCFD:Ortec and University of AlbertaScint:250 6 1.25cmThree movable cosmic ray telescopes in a logical OR.Scintillator is enclosed in a light-tight box (the coffin).
2004 IU Cosmic Rays SummaryAttenuation Length = 160.5 4.2 cmVelocity = 14.77 0.09 cm/nsTime Resolution = 88 ps
2005 TRIUMF Test Beam SummaryFirst two weeks of June 2005.120 and 250 MeV/c //e beams.Full size and half size scintillators.
2005 TRIUMF Test Beam SummarySame electronics as cosmic ray tests:PMT: XP2020TDC: LeCroy 2228A (50ps least count)ADC: LeCroy 2249A and IU fADCCFD: Ortec and University of AlbertaScint: 250 6 1.25cm
2005 TRIUMF Test Beam SummarySample ADC and TDC from one bar end. -- 120 MeV/c //e beam -- 3 Moyal distribution fit to ADC -- 3 Gaussian distribution fit to TDCe+e+++++
2005 TRIUMF Test Beam SummaryFour scans along a front bar.
Mean ADC from the two bar ends are superimposed.Attenuation Length = 136.7 3.4 cmpionmuonelectron
2005 TRIUMF Test Beam SummaryAnomalies in ADC vs TDCGoode+++Severetime-walkfor electrone+e+e+++++++Double-peakelectronDouble-peakmuon-- Similar behavior for both Alberta and Ortec CFD.-- Needs further analysis.-- Need more tests with different discriminators.
2005 TRIUMF Test Beam Summary/e separation/e separation/ separationFour scans along a front bar.
TDC differences from the two ends are superimposed.
Very consistent run to run results.
Nonlinearities are likely due toADC vs TDC anomalies.
Very Important. Needs to beinvestigated further.
Three Outstanding Design IssuesThe 88ps resolution for the 252 6 1.25cm bars is not acceptable. Try doubling the bar thickness.
Understand the discriminator issues. Try out a few commercial models (CFD and LED).
Explore different phototube options. Can we find something better than the XP2020 for timing and performance in a magnetic field?
Phase I Prototype (2006): CosmicsPLAN:Use the existing IU cosmic ray test stand to explore: -- bar thickness -- discriminators -- phototubesBUDGET:Phototubes: 12k (e.g. Hamamatsu R9779, Hamamatsu R2083, Hamamatsu R1828, Electron D744, Photek PMT340)Discriminators: 12k (e.g. Ortec 935, Phillips 7106, 708, 710, 715, 730)2006 Request = 24k
Phase II Prototype (2007): Test BeamPLAN:Test 2 walls of 10 scintillators each (one long horizontal wall and one short vertical wall) in November 2007 along with the LGD. -- use electrons and photons from Hall-B -- scan bars for time and position resolutions. -- correlate the timing with the LGD and the tagger.BUDGET:Phototubes: 18k (instrument 20 bars with XP2020)Scintillators: 5kHigh Voltage: 25kCables: 5kSupplies: 6k
2007 Request = 59k
Phase III Prototype (2008): MagnetPLAN:Test the prototype in the magnet fringe field.BUDGET:No new money anticiptated.2006-2008 Request = 83k