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234 U( n,f ) and 232 Th( n,f ). FIC – nTOF. Analysis of the detector signal. relative cross section calculation. “Average signals”. Pulse fitting. Select fitted pulses. “Gamma – Flash” fitting. “Gamma – Flash” fitting. Subtract “average signal”. Add same samples. Add fADC content.
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234U(n,f) and 232Th(n,f) FIC – nTOF
Analysis of the detector signal relative cross section calculation “Average signals” Pulse fitting Select fitted pulses “Gamma – Flash” fitting “Gamma – Flash” fitting Subtract “average signal” Add same samples Add fADC content Fit pulses Apply threshold End of run false End of run Threshold correction false true Create “average signals” true Calculate relative cross section to 235U and 238U Store results
Analysis of the detector signal Typical “average signals” These “averages” are fitted to the detector signal with the above function before are subtracted
Analysis of the detector signal Typical detectors signal pulse fitting Average signals are created for each fADC channel (magenta). From the detector signal (black) the average is subtracted (cyan). The pulses are fitted with the “pulse function” (red). “pulse function”
Analysis of the detector signal Correction for threshold Function used to fit the amplitude distribution Correction = (2nd Peak Integral with no threshold)/(2nd Peak Integral with threshold) Correction x YieldWithThreshold = Yieldcorrected 238U amplitude distribution of 234U run, correction = 1.2
Analysis of the detector signal σ(Εn) = f(σ(t), σ(d)) in the order of 10-3 σ(t) is both gamma flash and peak fitting error σ(d) is the error in the distance (0.5 mm) and in “ nTOF resolution function” ? For the calculation of relative cross section was used the “thin target approximation” formula σ(csrel) = f(σ(m), σ(Y)), both for measured and reference sample σ(m) is the sample mass error σ(Y) is the statistical error of the counts for each energy Both errors are plotted at the graphs presented The graphs have logarithmic binning and 500 bins per decade
234U fission campaign FIC targets* *source : Neutron Induced Fission Cross-Section Measurements with FICs Detectors. Vladimir Konovalov
Fission Yield Orange no threshold Black with threshold (400)
Efficiency correction due to threshold Amplitude distribution without threshold fitted to correct for the lost fission events. Threshold was set to 400. Correction = 1.2 Correction = 1.18 Correction = 1.14
238U cross section (derived from 238U relative cs to 235U and ENDF)
234U cross section (derived from 234U relative cs to 235U and ENDF)
232Th fission campaign FIC targets* *source : Neutron Induced Fission Cross-Section Measurements with FICs Detectors. Vladimir Konovalov
Fission Yield Orange no threshold Black with threshold (600)
Efficiency correction due to threshold Amplitude distribution without threshold fitted to correct for the lost fission events. Threshold was set to 600. Correction = 1.3 Correction = 1.25 Correction = 1.26
238U cross section (derived from 238U relative cs to 235U and ENDF)
232Th cross section (derived from 232Th relative cs to 235U and ENDF)