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

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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

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35 o

5.0 cm 5.0 cm

1.0 cm 2.5 cm