Sadiq Thesis
Introduction
Positron
Positron is the antimatter of electron. Positrons have same mass as electron (
), carries positive charge, and it is noted as " ".Positrons predicted by Paul Dirac in 1928, <ref name="Dirac1928"> The Quantum Theory of the Electron, P. A. M. Dirac, Proc. R. Soc. Lond. A February 1, 1928 117 778 610-624;</ref>, and experimentally observed by Dmitri Skobeltsyn in 1929 and by Carl D. Anderson in 1932 <ref name="e+_discover"> General Chemistry, Taylor and Francis. p. 660. </ref>. Anderson also coined the term positron and he won the Nobel Prize for Physics in 1936.
<ref name="name"> BOOK_Gernal, Auther, Month_Year,issue,page </ref>
Positron Beamline History
Theory
positron creation from Bremsstrahlung
Positron rate prediction
Apparatus
HRRL Positron Beamline
Beam properties
Emittance Measurement
Energy Spread Measurement
Current, rep-rate
Radiation Footprint
Positron detection
DAQ setup
Data Analysis
Signal extraction
For 3 MeV and on detector show all the steps
- Raw counts target in and out (calibrated energy)
- Normalized counts
- background subtracted
- Integral (zoomed in and with error)
Example of error propagation for the above
Raw counts target in and out
The counts shown in the integral is background subtracted spectrum. The red is signal and blue is background.
run in | run out | NaI Left: image with cut | NaI Right: image with cut | 3737 | 3736 | ![]() |
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Reprate = 300 Hz
Run time = 1094 s
Pulses = 329368
Events = 15361 (Hz)
e+ rate NaI Left = 276 +- 16.6132 (Hz).
Normalized counts
The ingeral shown in read is from the background is subtracted spectrum.
3735 and 3736
Reprate = 300 Hz
Run time = 1094 s
Pulses = 329368
Events = 15361
e- rate = 1.36517e+014 +- 2.39286e+012 (Hz)
e+ rate = 0.251457 +- 0.0151608 (Hz).
e+/e-=1.84195e-015+-1.11072e-016.
e- current:I_e- =1.52232e-005+-3.83378e-007 (A).
e+/I_e-=0.2515 Hz e+ / 15.22
A e-Background subraction
Sources of Systematic Errors
Efficiency measurement
acceptance, quad collection efficiency,
Conclusion
References
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