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Time-of-Flight and Position Resolution in Proposed Detectors
DR. WILLIAM TIREMANNORTHERN MICHIGAN UNIVERSITY
MR. DANIEL WILBERNNMU RESEARCH ASSISTANT
Goals Measure the dispersion in the time-of-flight of cosmic rays between two plastic scintillator detectors Measure the position resolution for a cosmic ray hit on the test detector
Neutron Research Red – charged particle taggers
Green – Neutron Bars
Neutrons knock protons out and they scatter up and down into the detectors
Picture from: Dr. Andrei Semenov, University of Regina, Canada
Pictures from: Dr. Andrei Semenov, University of Regina, Canada
General Detector Setup/Circuit
To linear sum
Canberra
Multi !port MCA Desktop
Computer USB
HV
HV HV
Delay box
HV
ORTEC 583 CFD
ORTEC 566 TAC
Lecroy 465 Coincidence
KSU Linear Fan Out
KSU Mean Timer
ORTEC583 CFD
KSU Linear Fan Out
To linear sum
KSU Linear Fan Out
ORTEC566 TAC
Delay box
Gate
Stop Start
Delay box
Gate
Stop
Lecroy 465 Coincidence
ORTEC583 CFD
ORTEC583 CFD
KSU Mean Timer
Delay box
Delay box
Used as linear fan
Start
2 1Position
Measurement Time!of !Flight Measurement
Measurement Parameters
Vertical tracks selected by limiting energy deposited in small detector (1.0 cm width) via CFD lower level discriminator
Small detector was positioned over location on test detector with 5.0 cm axis in the vertical to give largest energy deposition in small detector
Coincidence requirement between mean-time signal in the test detector and the small detector was formed with LeCroy 465 unit
Two Ortec 566 TAC were then gated with the coincidence signal Position spectrum was formed by starting the TAC with the ‘left’ PMT and stopping it with
the ‘right’ PMT (converted to position via ) Time-of-flight spectrum was formed by starting a second TAC with the mean-time signal
from the small detector and stopping it with the mean-timed signal from the test detector
All TAC signals were then converted to histograms via Canberra multiport, multichannel analyzer and analyzed with MatLab code
Typical Spectra
Plan A – 120o Bend Configuration
Location along Detector from
CenterLive Time
Count Rate per minute
Position Δt
Uncert.
FWHM Position Uncert.
FWHM TOF
Uncert.
Time Dispersion
s cnt/min Sigma (ps) FWHM (ps) ps Sigma (cm) FWHM (cm) cm Sigma (ps) FWHM (ps) ps psLeft Side 5.0 cm 62369 1.90 188.2 443.2 7.6 3.63 8.55 0.03 193.3 455.2 2.0 321.9Left Side 50.0 cm 86574 1.71 194.1 457.1 7.1 3.77 8.87 0.03 164.7 387.8 1.3 274.2Left Side 75.0 cm 92173 1.04 200.0 470.9 10.7 3.95 9.31 0.05 224.1 527.6 2.3 373.1Right Side 5.0 cm 181094 0.33 144.3 339.7 11.0 2.97 7.00 0.05 164.6 387.6 2.8 274.1Right Side 50.0 cm 79291 1.38 180.1 424.2 7.5 3.48 8.20 0.03 199.8 470.5 3.0 332.7Right Side 75.0 cm 179514 0.62 236.7 557.3 14.3 4.54 10.7 0.06 190.6 448.8 3.0 317.3
average 448.7 ps 8.91 cm 446.3 ps 315.5 psSD 70.5 ps 0.38 cm 53.2 ps 37.6 psSD of Mean 11.8 ps 0.13 cm 8.9 ps 15.4 ps
Detector Plan A 120o Bend
Position ResolutionTime-of-Flight
Resolution Position Spectrum Time
Analysis
Plan B – 90o Configuration
Distance from 90o
endLive Time
Count Rate per minute
Position Δt
Uncert.
FWHM Position Uncert.
FWHM TOF
Uncert.
Time Dispersion
s cnt/min Sigma (ps) FWHM (ps) ps Sigma (cm) FWHM (cm) cm Sigma (ps) FWHM (ps) ps ps15.0 cm 84689 1.37 150.4 354.1 5.4 2.90 6.82 0.02 140.1 329.8 1.1 233.225.0 cm 87297 1.17 136.7 321.9 4.9 2.65 6.25 0.02 136.0 320.3 1.2 226.535.0 cm 84589 1.17 144.3 339.9 6.3 2.80 6.60 0.03 139.3 328.1 1.0 232.050.0 cm 67250 1.22 144.9 341.2 7.8 2.85 6.71 0.03 141.4 332.9 1.3 235.465.0 cm 151115 1.08 141.9 334.2 4.6 2.74 6.45 0.02 128.6 302.8 1.0 214.175.0 cm 84300 1.10 151.0 355.6 6.1 2.91 6.85 0.03 137.1 322.9 1.0 228.385.0 cm 89364 0.87 158.9 374.2 6.2 3.07 7.23 0.03 138.4 326.0 1.4 230.595.0 cm 84972 0.79 162.8 383.3 8.1 3.12 7.35 0.04 169.3 398.6 1.6 281.9
average 350.6 ps 6.78 cm 333.1 ps 235.2 psSD 20.6 ps 0.40 cm 30.4 ps 19.9 psSD of Mean 2.6 ps 0.08 cm 6.1 ps 7.0 ps
Detector Plan B 90o Bend
Position ResolutionTime-of-Flight
Resolution Position Spectrum
Time Analysis
Conclusion
Assume detectors contribute to time dispersion in equally so time dispersion is divided by The Plan B configuration (90o bend on 1-meter detector) has a better time dispersion and position resolution Plan B will be easier to build and will be more robust Plan B gives more segmentation Plan A covers more acceptance Plan A requires fewer electronics Work Continues on using two detectors for defining vertical geometry
Configuration Position Resolution
(cm)
Position ΔT FWHM (ps)
Time Dispersion (ps)
Plan A 8.91 ± 0.13 446 ± 9 316 ± 15
Plan B 6.78 ± 0.08 333 ± 6 235 ± 7
Madey et. al. < 2.5 NA 155 ± 5
ReferencesMadey, R. et al. (1983). Large volume neutron detectors with subnanosecond time dispersions. Nuclear Instruments and Methods in Physics Research, 214(2-3), 401-413 doi: 10.1016/0167-5087(83)90608-7
Using Small Detector Energy to Limit Cosmic Ray Incident Angle
1.0 cm
5.0 cm
10 cm
2.0 cm 4.0 cm0.0 cm 6.0 cm 8.0 cm 10.0 cm
0o 10 o
20 o
30 o
5o 15 o
25 o
Using Small Detector Energy to Limit Cosmic Ray Incident Angle
Using Small Detector Energy to Limit Cosmic Ray Incident Angle
8.9 cm
5.0 cm
10 cm
2.0 cm 4.0 cm0.0 cm 6.0 cm
12.5 cm
41 o 41 o
2.7 cm
9.5 cm
Using Small Detector Energy to Limit Cosmic Ray Incident Angle
0o 10 o 20 o
30 o
5o 15 o25 o
0o 10 o 20 o
30 o
40 o
5o 15 o
25 o
35 o
5.0 cm 5.0 cm
1.0 cm 2.5 cm