The Time of Flight Detector for GlueX at Jefferson Lab Hussein Al Ghoul University of Kansas
Overview The GlueX Experiment The Time of Flight Detector Pre-Construction Testing TOF Construction at Florida State University TOF Assembly at Jefferson Lab
The GlueX Experiment The 12 GeV upgrade at Jefferson Lab Addition of ten new High-voltage croyomodules Ten new RF stations Double the Refrigeration capacity Modifications to the magnets Modifications to the extraction system A tenth arc-beamline A new beamline connected to Hall D Construction of hall D for the GlueX detector Continuous Electron Beam Accelerator Facility
The GlueX Experiment The Detector
The Time of Flight Detector Proposed Design
The Time of Flight Detector Design Details Hamamatsu H10534 Ultra-fast PMT 10 stages, 250ps spread PMT connected to a light guide that is glued to scintillator bar
Pre-construction Testing PMT Testing: Gain HP / Agilent 8116A Pulse/Function Generator - Single Photoelectron peak from pulsed UV LED measurements - Gains ranging between 2.1x106 and 7.6x106 - Measured values deviated by 10-20% from Hamamatsu Specifications
Pre-construction Testing PMT Testing: Linearity of PMT response - Using a UCS-20 USB spectrometer - 133Ba and 137Cs sources with NaI crystal - In addition to 662 kev peak of 137Cs, two peaks of 133Ba spectrum 81 kev and 356 kev are measured with each PMT and used to calibrate the linear energy scale of the spectrometer - Energy-calibrated position of 662 kev peak provides a measure of the linearity of tube's response - Average deviation from 662 kev position was about 0.4% and did not exceed 2.9%
Pre-construction Testing PMT Testing: Relative Quantum Effeciency σ/emean ~ 1/ Npe (Poisson statistics) Quantum efficiency Q.E. = Npe/ Nγ Assuming constant Nγ: Q.E. ~ Npe~ (Emean/σ)2 which has the spread of about 4% (average) and 19% (max) over all measured tubes
Pre-construction Testing 4 wrapping material options: ViKuiti Enhanced Specular Reflector (ESR), Mylar, Tyvek, and Aluminum foil. Reflective Material Choice ADC peak positions: Mylar ESR 1800V: 1101 1472 2000V: 1801 2444 ADC pedestal: 267 ESR wrapping preserves 40-45% more light ESR/Mylar ratio: 1800V: (1472-267)/(1101-267)=1.45 2000V: (2444-267)/(1801-267)=1.42
Pre-construction Testing L Reflective Material Choice AL AR BL BR R ta = (AL+AR)/2 ttof = ta + tref/2 = (AL+AR+BL+BR)/4 tb = (BL+BR)/2 But also ttof = (L+R)/2 tref = (BL+BR-AL-AR)/2 ΔtAB = (L+R)/2 - (AL+AR+BL+BR)/4 σ2(ttof) = σ2(δtab) σ2(tref)/2 ESR: Mylar: σtof = (3.0222-2.7682/2) = σtof = (2.8152-2.4632/2) = 2.30 counts = 2.21 counts = 130.3 ± 3.1 ps 125.2 ± 3.0 ps
Pre-construction Testing Scintillator Bars Attenuation Length Taking the ratio of amplitude from left and right PMT avoids the LED instability
Pre-construction Testing PMT Matching
TOF Construction at FSU Light Guides
TOF Construction at FSU Gluing light guides to scintillator bars
TOF Construction at FSU Gluing light guides to scintillator bars
TOF Construction at FSU Wrapping Modules with ESR
TOF Construction at FSU Wrapping Modules with ESR
TOF Assembly at Jlab
TOF Assmebly at Jlab
Thank You