 Sun Apr 5 20:34:42 2020, Laszlo, Calibration, Xray energies - 1. calibration, 8x
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30angle: E[keV] = 0.0158507 *ch-2.07456
90angle: E[keV] = 0.01950*ch-2.76
145angle: E[keV] = 0.017988 *ch-1.809
I could identify 2 peaks in the 241Am spectra and 4 peaks in the 133Ba. These peaks are fitted with a gaussian to get their position --> linear energy calibration for the combined (Am+Ba) data sets for each detector. The function I used: E(ch) [keV] = m*ch+b |
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Mon Apr 6 04:39:19 2020, Laszlo, Calibration, 2. Xray energy calibration, 9x
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30angle: E[keV] = 0.015898 *ch-1.91
90angle: E[keV] = 0.0211075*ch-2.39
145angle: E[keV] = 0.01663 *ch-1.758 |
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Mon Apr 6 23:00:51 2020, Laszlo, Calibration, beam energies for 124Xe and 118Te measurements,
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"The e- cooler settings were the same for the 124Xe and 118Te beams" - Sergey --> speed of the ions is the same --> same MeV/u
E_beam = 10.0606MeV/u
The uncertainty on the cooloer values should be asked from Markus/Regina |
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Wed Apr 8 20:06:10 2020, Laszlo, Calibration, Counts in the K-REC peaks,
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3 datasets were investigated:
-124Xe with Scraper (2. Xray calibration parameters needed)
-124Xe without Scraper (2. Xray calibration parameters needed)
-118Te with Scraper (1. Xray calibration parameters needed)
I looked all the 35°, 90° and 145° detector spectra:
-For both Xe measurements all 3 detector signal can be evaluated
-For Te beam one can see only in the 145° detector spectra the Kalpha and K-REC peaks (with high uncertainty). For the 35° probably the detector was simply not sensitive enough for such low beam intensities. For the 90° case, I am much surprised, the peaks supposed to be there the most prominent of all. In the spectra, I maybe can recognize a peak at ~27,8keV, but this is even in best case only the Kalpha peak. At the range of the expected K-REC (~40keV), there is a bit of increase in the background overlying the peak. This background increase is also in the background spectra. Also probably this twisted cables issue between 90° and 145° didn't help much. I think anyhow, that maybe this must have some noise related origin. I can remember that the cables (despite all of our and Uwe's tries) were not well grounded, the noise level was kind of floating.
In general, I would also remark that we can see some peaks >60keV in the background, but these luckily don't disturb us.
To evaluate the Xray spectra I used the following algorithm:
1, for each type of beams I used the list of event numbers in the next entry (to exclude "bad" events)
To get the Kalpha and K-REC and other peaks I used the condition trigger==1 (jet ON)
To get the background spectra, I used trigger==2 (Jet OFF). The background spectra is only used to see that there is no underlying peak structure below K-REC. To subtract count, the background histo was NOT in use.
2, While using a well-suiting number of bins, I plot the JetON and JetOFF histos.
By eye I choose the range of the K-REC peak and the range for the background fit on the JetON histo. Ofc range_bckgnd > range_peak.
Simultaneously, I check on the JetOFF histo that both, in the fit-range and in the peak-range, there should not be any peak structure visible.
3, For the fit-range in JetON histo, excluding the peak-range, I fit a linear function, m*x+b. For each bin in the fit-range I subtract m*bin_center+b value from the bin content. After the subtraction I check if I got spectra looking like a single peak sitting on a zero
line.
4, To get the K-REC counts, I sum together all the bin values for each bin of the subtracted histo within the peak-range. For the error calculation, I use Gaussian error prop. The uncertainty of the JetON histo counts = sqrt(counts). Also for the subtraction I make the
error like delta(m*bin_center+b)= sqrt(m*bin_center+b) instead using the uncertainty of the fit parameters. This second one wont make much sense, since the slope of the linear fit is usually close to 0 --> the errors grow unrealistically big.
Based on the algorithm above I got the following counts:
-124Xe with Scraper:
35°: 174 +/- 15
90°: 21299 +/- 150
145°: 2104 +/- 52
-124Xe without Scraper:
35°: 65 +/- 9
90°: 7792 +/- 91
145°: 728 +/- 31
-118Te_part1 with Scraper:
35°: -
90°: 427 +/- 40
145°: -
-118Te_part2 with Scraper:
35°: -
90°: 741 +/- 48
145°: -
-124Xe_lowRate with Scraper:
35°: -
90°: 2121 +/- 52
145°: - |
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Wed Apr 8 23:02:24 2020, Laszlo, General, lmd to measurement pairing list,
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I use the following list of lmd files combined to a single root file for each measurement.
It is very important to highlight that sometimes the trigger==1 data got corrupted,massive number of trigger==2 like events appear on the detector as trigger==1 signal, because the gas jet target didn't switch off after its normal phase (gas jet remains ON during injection. Maybe some gas jet issue, maybe some bug in the pattern :/ ). To correct for this, one has to cut out these parts from the data. I did these cut outs by hand while looking at the event number vs I_ESR & density gas jet plot (see below). Probably this can be done also in a more automatized way, but I think this is not necessary. In the "124Xe with Scraper" data set it is only 1 time like this, in the 118Te data set 3 times. The other data sets seem fine to me.
-124Xe with scraper:
run090_0001.lmd run091_0001.lmd run092_0001.lmd run094_0001.lmd run095_0001.lmd run096_0001.lmd run098_0001.lmd run099_0001.lmd
if(!(i>1634880 && i<1652240)){do analysis} - (this if condition is valid only if one combines the lmd in numerical order)
(2. Xray calibration parameters)
-124Xe without scraper:
run100_0001.lmd run101_0001.lmd run102_0001.lmd run104_0001.lmd
if(true){do analysis}
(2. Xray calibration parameters)
-118Te with scraper:
run051_0001.lmd run053_0001.lmd run055_0001.lmd run057_0001.lmd run059_0001.lmd run064_0001.lmd run066_0001.lmd
run052_0001.lmd run054_0001.lmd run056_0001.lmd run058_0001.lmd run060_0001.lmd run065_0001.lmd run067_0001.lmd
Changing Xray cables!
run068_0001.lmd run070_0001.lmd run072_0001.lmd run074_0001.lmd run076_0001.lmd run078_0001.lmd run080_0001.lmd run082_0001.lmd run084_0001.lmd run086_0001.lmd
run069_0001.lmd run071_0001.lmd run073_0001.lmd run075_0001.lmd run077_0001.lmd run079_0001.lmd run081_0001.lmd run083_0001.lmd run085_0001.lmd run087_0001.lmd
For Xray analysis:
1. dataset:
Xray[2] = 90 degree Xray[1]=145degree. The timing is switched:
if(!(i>1801830 && i<1807810) && !(i>2348370 && i<2355110)){
if(t_Xray[2]>0) Xray[1] ->Fill();
if(t_Xray[1]>0) Xray[2] ->Fill();
}
(1. Xray calibration parameters --> invalid!)
2. dataset:
if(!(i>5488450-2507171 && i<6125720-2507171)){do analysis}
(2. Xray calibration parameters)
For Si analysis:
if(trigger==1 && !(i>1801830 && i<1807810) && !(i>2348370 && i<2355110) && !(i>5488450 && i<6125720) ){do analysis}
(1. Xray calibration parameters)
-124Xe with scraper - low rate measurement
run046_0001.lmd run047_0001.lmd run047_0003.lmd run048_0002.lmd run049_0002.lmd run050_0001.lmd
run046_0002.lmd run047_0002.lmd run048_0001.lmd run049_0001.lmd run049_0003.lmd run050_0002.lmd
if(true){do analysis}
(1. Xray calibration parameters --> invalid!)
Regarding the gain matching, I assumed that the same 2*16 factors can be used for all data sets, since we didn't change bias voltage (the current remained roughly also the same) and also the detector didn't get any serious radiation damage (this needs to be confirmed!).
A more detailed anaylsis will come on the gain matching after the Easter holiday.
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Tue Apr 21 22:25:00 2020, Jan, Analysis, ,
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Thu Apr 23 19:09:58 2020, Laszlo, Calibration, theoretical K-REC cross sections , 9x
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Find attached Andrey Surzhykov's calculations for the theta angle in respect to the beam direction (in lab. frame) vs. cross section for 124Xe54+ and 118Te52+.
The calculations made for collision with two H atoms with the accuracy of 1%. There are no molecular corrections done, but these corrections are within 1%.
The photon-emission is symmetrical in the azimuthal phi angle, but asymetric in theta. The K-REC cross section is given for each integer theta angle. The problem is that our 90° and 145° xray detectors cover more integer theta-angles --> The disk shaped entrance window of the Xray-detectors is sliced for each covered theta angles, and the CS values are averaged together with the weights of the area of the corresponding slice. The 35° det had a non-disk shaped slit collimator! Was it aligned vertical or horizontal or random? I assumed that it had a vertical position --> only cs at theta=35° needs to taken into account
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| 90° | 145° | 35°
| | weighted cs_Xe [barn/sr] | 128,444 | 41,967 | 45,550
| | weighted cs_Te [barn/sr] | 118,616 | 38,918 | 41,740
|
For the steradian values I calculated the area of the entrance window of the Xray detectors and I divided it with the area of the sphere with radius = distance between source and det. If r=radius of the entrance window, D=distance between source and det.: covered steradian = r^2*pi/(4*pi*D^2) [%], covered steradian = 4Pi*[r^2*pi/(4*pi*D^2)] [4pi]. This is valid for the 90° and 145° Xray detectors. The area of 35° det. was calculated individually.
|
| 90° | 145° | 35°
| | sr [%] | 0,00237 | 0,00076 | 0,00002
| | sr [4pi] | 0,0298 | 0,0096 | 0,00030
|
I converted barn/sr to barn in the following way: steradian[4pi]*weigthed_cs [barn/sr] = weigthed_cs [barn]. I am not 100% sure if I need here the steradian in [4pi] or in [%].
|
| 90° | 145° | 35°
| | weighted cs_Xe [barn] | 3,8247 | 0,4012 | 0,0137
| | weighted cs_Te [barn] | 3,5321 | 0,3720 | 0,0125
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Wed Apr 29 16:06:28 2020, Laszlo, Calibration, efficiency fit - 90degree, combined dataset,
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For the efficiency vs E fit of the 90degree Xray detector I have used the following phenomenological funciton:
f(x) = a * (1-exp(-(x-c)/b)) * exp(-x/d)
Here the first exponent member is a saturation curve. This part describes the passing through of the two Be windows (chamber + before detector) and through the dead layer of Ge crystal. One needs a minimum energy to enter to the detecting Ge crystal = C parameter. b parameter = characteristic absorbtion E of these nondetecting layers.
The second exponent is an exponential decrease of the detector efficiency. Photons with higher energy are less detectable by the germaniums. The d parameter is the characteristic E for hard Xray and gamma (>40keV) detectability.
https://www.amptek.com/internal-products/si-pin-vs-cdte-comparison
//Jan's comment: the tail of this function should more or less follow a linear trend a bit above than 40 keV.
In the attachment there is an example fit for 90 degree with combined 1. and 2. (before and after beamtime) calibration datasets.
I made the fit with gnuplot:
degrees of freedom (FIT_NDF) : 8
rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.419915
variance of residuals (reduced chisquare) = WSSR/ndf : 0.176329
p-value of the Chisq distribution (FIT_P) : 0.994094
Final set of parameters Asymptotic Standard Error
======================= ==========================
a = 0.00308376 +/- 0.0005144 (16.68%)
c = 15.6259 +/- 2.035 (13.03%)
b = 9.36888 +/- 3.16 (33.73%)
d = 177.141 +/- 84.95 (47.95%)
Laszlo's out. |
 Thu Apr 30 17:40:57 2020, Laszlo, Calibration, efficiency fits,
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For all 3 detector the calibration data sets were combined to include the systematics in the fit results directly. Combining means not a weighted average, just simple all data points were included into the fit --> doubled efficiency value for most of the energies.
The g(x) = a * (1-exp(-(x-c)/b)) * exp(-x/d) function was used to describe the behavior of the Germanium detectors for the whole range of energies (global behavior). From these fits the 80keV outlier point was excluded. This is very strange that it doesn't follow the trend, it would be nice to find out why not.
Between 40-75keV a linear fit was carried out as well. This can also approximate quite well this local energy range, what we need for the K-REC peaks.
l(x) = m*x+e
All the fits were done by gnuplot, but it was also confirmed that ROOT gives us the same parameters + errors + chisquare. One just need to choose well the starting values :)
90° fits:
degrees of freedom (FIT_NDF) : 8
rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.419915
variance of residuals (reduced chisquare) = WSSR/ndf : 0.176329
p-value of the Chisq distribution (FIT_P) : 0.994094
Final set of parameters Asymptotic Standard Error
======================= ==========================
a = 0.00308376 +/- 0.0005144 (16.68%)
c = 15.6259 +/- 2.035 (13.03%)
b = 9.36888 +/- 3.16 (33.73%)
d = 177.141 +/- 84.95 (47.95%)
degrees of freedom (FIT_NDF) : 4
rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.283372
variance of residuals (reduced chisquare) = WSSR/ndf : 0.0802998
p-value of the Chisq distribution (FIT_P) : 0.988405
Final set of parameters Asymptotic Standard Error
======================= ==========================
m = -6.22672e-06 +/- 1.836e-06 (29.48%)
e = 0.00256426 +/- 9.873e-05 (3.85%)
145° fits:
degrees of freedom (FIT_NDF) : 6
rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.379472
variance of residuals (reduced chisquare) = WSSR/ndf : 0.143999
p-value of the Chisq distribution (FIT_P) : 0.990247
Final set of parameters Asymptotic Standard Error
======================= ==========================
a = 0.0012346 +/- 0.0006794 (55.03%)
c = 11.3754 +/- 4.075 (35.82%)
b = 15.6961 +/- 13.2 (84.1%)
d = 116.084 +/- 99.83 (86%)
degrees of freedom (FIT_NDF) : 2
rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.327728
variance of residuals (reduced chisquare) = WSSR/ndf : 0.107405
p-value of the Chisq distribution (FIT_P) : 0.898161
Final set of parameters Asymptotic Standard Error
======================= ==========================
m = -2.39246e-06 +/- 1.278e-06 (53.42%)
e = 0.000848859 +/- 7.329e-05 (8.634%)
35° fit:
degrees of freedom (FIT_NDF) : 7
rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 1.40676
variance of residuals (reduced chisquare) = WSSR/ndf : 1.97896
p-value of the Chisq distribution (FIT_P) : 0.0538635
Final set of parameters Asymptotic Standard Error
======================= ==========================
a = 0.000114396 +/- 0.0002367 (206.9%)
c = 14.3178 +/- 8.322 (58.13%)
b = 16.7454 +/- 43.21 (258%)
d = 79.7991 +/- 173.2 (217.1%)
degrees of freedom (FIT_NDF) : 3
rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 1.21233
variance of residuals (reduced chisquare) = WSSR/ndf : 1.46975
p-value of the Chisq distribution (FIT_P) : 0.220529
Final set of parameters Asymptotic Standard Error
======================= ==========================
m = -3.7879e-07 +/- 3.143e-07 (82.99%)
e = 7.31447e-05 +/- 1.788e-05 (24.45%)
> For the efficiency vs E fit of the 90degree Xray detector I have used the following phenomenological funciton:
>
> f(x) = a * (1-exp(-(x-c)/b)) * exp(-x/d)
>
> Here the first exponent member is a saturation curve. This part describes the passing through of the two Be windows (chamber + before detector) and through the dead layer of Ge crystal. One needs a minimum energy to enter to the detecting Ge crystal = C parameter. b parameter = characteristic absorbtion E of these nondetecting layers.
> The second exponent is an exponential decrease of the detector efficiency. Photons with higher energy are less detectable by the germaniums. The d parameter is the characteristic E for hard Xray and gamma (>40keV) detectability.
>
> https://www.amptek.com/internal-products/si-pin-vs-cdte-comparison
>
> //Jan's comment: the tail of this function should more or less follow a linear trend a bit above than 40 keV.
>
>
> In the attachment there is an example fit for 90 degree with combined 1. and 2. (before and after beamtime) calibration datasets.
> I made the fit with gnuplot:
>
> degrees of freedom (FIT_NDF) : 8
> rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.419915
> variance of residuals (reduced chisquare) = WSSR/ndf : 0.176329
> p-value of the Chisq distribution (FIT_P) : 0.994094
>
> Final set of parameters Asymptotic Standard Error
> ======================= ==========================
> a = 0.00308376 +/- 0.0005144 (16.68%)
> c = 15.6259 +/- 2.035 (13.03%)
> b = 9.36888 +/- 3.16 (33.73%)
> d = 177.141 +/- 84.95 (47.95%)
>
> Laszlo's out. |
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Thu Apr 30 22:55:45 2020, Laszlo, Calibration, inverse square law test,
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I have made also the inverse square law fits. We have data only for 90degre with the 241Am source, but both for the 1. and 2. calibrations. The 1. and 2. calibration data sets treated separate.
2 peaks were investigated, 59.5keV and 26.3keV, at two distances 184.8mm and 217.3mm. These distances are the sum of 4 distances:
a = width of plastic head. uncert.: +/- 0.05mm, measured with caliper.
b = width of the brass collimator. uncert.: +/- 0.05mm, measured with caliper.
c = width of protector plastic ring. uncert.: +/- 0.05mm, measured with caliper.
d= distance of the paper head. uncert: +/- 0.5mm, judged by the eye :)
The Be window and the dead layer of the Ge detector is not taken into account.
The distances calculated as D=a+b+c+d.
The conclusion is that the uncertainty coming from the distance measurements are negligible compared to the other uncertainties. The data obey the inverse square law.
> For all 3 detector the calibration data sets were combined to include the systematics in the fit results directly. Combining means not a weighted average, just simple all data points were included into the fit --> doubled efficiency value for most of the energies.
> The g(x) = a * (1-exp(-(x-c)/b)) * exp(-x/d) function was used to describe the behavior of the Germanium detectors for the whole range of energies (global behavior). From these fits the 80keV outlier point was excluded. This is very strange that it doesn't follow the trend, it would be nice to find out why not.
> Between 40-75keV a linear fit was carried out as well. This can also approximate quite well this local energy range, what we need for the K-REC peaks.
> l(x) = m*x+e
>
> All the fits were done by gnuplot, but it was also confirmed that ROOT gives us the same parameters + errors + chisquare. One just need to choose well the starting values :)
>
>
> 90° fits:
> degrees of freedom (FIT_NDF) : 8
> rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.419915
> variance of residuals (reduced chisquare) = WSSR/ndf : 0.176329
> p-value of the Chisq distribution (FIT_P) : 0.994094
>
> Final set of parameters Asymptotic Standard Error
> ======================= ==========================
> a = 0.00308376 +/- 0.0005144 (16.68%)
> c = 15.6259 +/- 2.035 (13.03%)
> b = 9.36888 +/- 3.16 (33.73%)
> d = 177.141 +/- 84.95 (47.95%)
>
> degrees of freedom (FIT_NDF) : 4
> rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.283372
> variance of residuals (reduced chisquare) = WSSR/ndf : 0.0802998
> p-value of the Chisq distribution (FIT_P) : 0.988405
>
> Final set of parameters Asymptotic Standard Error
> ======================= ==========================
> m = -6.22672e-06 +/- 1.836e-06 (29.48%)
> e = 0.00256426 +/- 9.873e-05 (3.85%)
>
>
>
> 145° fits:
> degrees of freedom (FIT_NDF) : 6
> rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.379472
> variance of residuals (reduced chisquare) = WSSR/ndf : 0.143999
> p-value of the Chisq distribution (FIT_P) : 0.990247
>
> Final set of parameters Asymptotic Standard Error
> ======================= ==========================
> a = 0.0012346 +/- 0.0006794 (55.03%)
> c = 11.3754 +/- 4.075 (35.82%)
> b = 15.6961 +/- 13.2 (84.1%)
> d = 116.084 +/- 99.83 (86%)
>
> degrees of freedom (FIT_NDF) : 2
> rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.327728
> variance of residuals (reduced chisquare) = WSSR/ndf : 0.107405
> p-value of the Chisq distribution (FIT_P) : 0.898161
>
> Final set of parameters Asymptotic Standard Error
> ======================= ==========================
> m = -2.39246e-06 +/- 1.278e-06 (53.42%)
> e = 0.000848859 +/- 7.329e-05 (8.634%)
>
>
>
> 35° fit:
> degrees of freedom (FIT_NDF) : 7
> rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 1.40676
> variance of residuals (reduced chisquare) = WSSR/ndf : 1.97896
> p-value of the Chisq distribution (FIT_P) : 0.0538635
>
> Final set of parameters Asymptotic Standard Error
> ======================= ==========================
> a = 0.000114396 +/- 0.0002367 (206.9%)
> c = 14.3178 +/- 8.322 (58.13%)
> b = 16.7454 +/- 43.21 (258%)
> d = 79.7991 +/- 173.2 (217.1%)
>
> degrees of freedom (FIT_NDF) : 3
> rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 1.21233
> variance of residuals (reduced chisquare) = WSSR/ndf : 1.46975
> p-value of the Chisq distribution (FIT_P) : 0.220529
>
> Final set of parameters Asymptotic Standard Error
> ======================= ==========================
> m = -3.7879e-07 +/- 3.143e-07 (82.99%)
> e = 7.31447e-05 +/- 1.788e-05 (24.45%)
>
>
>
> > For the efficiency vs E fit of the 90degree Xray detector I have used the following phenomenological funciton:
> >
> > f(x) = a * (1-exp(-(x-c)/b)) * exp(-x/d)
> >
> > Here the first exponent member is a saturation curve. This part describes the passing through of the two Be windows (chamber + before detector) and through the dead layer of Ge crystal. One needs a minimum energy to enter to the detecting Ge crystal = C parameter. b parameter = characteristic absorbtion E of these nondetecting layers.
> > The second exponent is an exponential decrease of the detector efficiency. Photons with higher energy are less detectable by the germaniums. The d parameter is the characteristic E for hard Xray and gamma (>40keV) detectability.
> >
> > https://www.amptek.com/internal-products/si-pin-vs-cdte-comparison
> >
> > //Jan's comment: the tail of this function should more or less follow a linear trend a bit above than 40 keV.
> >
> >
> > In the attachment there is an example fit for 90 degree with combined 1. and 2. (before and after beamtime) calibration datasets.
> > I made the fit with gnuplot:
> >
> > degrees of freedom (FIT_NDF) : 8
> > rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.419915
> > variance of residuals (reduced chisquare) = WSSR/ndf : 0.176329
> > p-value of the Chisq distribution (FIT_P) : 0.994094
> >
> > Final set of parameters Asymptotic Standard Error
> > ======================= ==========================
> > a = 0.00308376 +/- 0.0005144 (16.68%)
> > c = 15.6259 +/- 2.035 (13.03%)
> > b = 9.36888 +/- 3.16 (33.73%)
> > d = 177.141 +/- 84.95 (47.95%)
> >
> > Laszlo's out. |
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Wed May 6 23:02:42 2020, Laszlo, Calibration, efficiency values,
|
I have calculated the efficiency values by putting the energies of the K-REC peaks into the phenomenological (empirical) function and into the linear function (see below). The K-REC peak's position I got from a Gaussian-fit on the peak. There are 5 data sets in total:
With 1. E-calibration parameters:
-124Xe low rate measurement
-118Te 1. data set (before cable-swap)
With 2. E-calibration parameters:
-118Te 2. data set (after cable-swap)
-124Xe with scraper
-124Xe without scraper
When using the 1. E-calibration parameters, the obtained K-REC energies were much offset (124Xe_lowRate E_KREC=4.00577e+01keV, 118Te_1dataset: E_KREC=3.70922e+01keV), even though I tried all possible linear combinations of the parameters for 90° and 145°. Therefore, at the end I used the theoretical energies of the K-REC peaks from Thomas's website: http://www-ap.gsi.de/Thomas/ap_html_research/energy/index.php
Most probably, the problem is not with the 1. E-calibration itself (the source measurement looks consistent), but with the changing gate width during these measurements. These problematic data sets I marked with a " * " in the tables.
90°:
|
| 124Xe_wScraper | 124Xe_woScraper | 118Te_wScraper_part1 | 118Te_wScraper_part2 | 124Xe_wScraper_lowRate
| | K-REC E [keV] | 4,6093E+01 | 4,6116E+01 | *4,3241E+01 | 4,3135E+01 | *4,6336E+01
| | g(E_KREC) (phenomenology) | 0,002285 | 0,002285 | *0,002289 | 0,002289 | *0,002284
| | l(E_KREC) (linear) | 0,002277 | 0,002277 | *0,002295 | 0,002296 | *0,002276
| | diff. betw. f(E_KREC) and g(E_KREC) | 0,35% | 0,35% | 0,26% | 0,29% | 0,38%
|
145°:
|
| 124Xe_wScraper | 124Xe_woScraper
| | K-REC E [keV] | 4,1292E+01 | 4,1275E+01
| | g(E_KREC) (phenomenology) | 0,000736 | 0,000736
| | l(E_KREC) (linear) | 0,000750 | 0,000750
| | diff. betw. f(E_KREC) and g(E_KREC) | 1,82% | 1,83%
|
35°:
|
| 124Xe_wScraper | 124Xe_woScraper
| | K-REC E [keV] | 5,2309E+01 | 5,2478E+01
| | g(E_KREC) (phenomenology) | 0,0000532 | 0,0000532
| | l(E_KREC) (linear) | 0,0000533 | 0,0000533
| | diff. betw. f(E_KREC) and g(E_KREC) | 0,15% | 0,13%
|
> I have made also the inverse square law fits. We have data only for 90degre with the 241Am source, but both for the 1. and 2. calibrations. The 1. and 2. calibration data sets treated separate.
> 2 peaks were investigated, 59.5keV and 26.3keV, at two distances 184.8mm and 217.3mm. These distances are the sum of 4 distances:
> a = width of plastic head. uncert.: +/- 0.05mm, measured with caliper.
> b = width of the brass collimator. uncert.: +/- 0.05mm, measured with caliper.
> c = width of protector plastic ring. uncert.: +/- 0.05mm, measured with caliper.
> d= distance of the paper head. uncert: +/- 0.5mm, judged by the eye 
>
> The Be window and the dead layer of the Ge detector is not taken into account.
>
> The distances calculated as D=a+b+c+d.
>
> The conclusion is that the uncertainty coming from the distance measurements are negligible compared to the other uncertainties. The data obey the inverse square law.
>
>
> > For all 3 detector the calibration data sets were combined to include the systematics in the fit results directly. Combining means not a weighted average, just simple all data points were included into the fit --> doubled efficiency value for most of the energies.
> > The g(x) = a * (1-exp(-(x-c)/b)) * exp(-x/d) function was used to describe the behavior of the Germanium detectors for the whole range of energies (global behavior). From these fits the 80keV outlier point was excluded. This is very strange that it doesn't follow the trend, it would be nice to find out why not.
> > Between 40-75keV a linear fit was carried out as well. This can also approximate quite well this local energy range, what we need for the K-REC peaks.
> > l(x) = m*x+e
> >
> > All the fits were done by gnuplot, but it was also confirmed that ROOT gives us the same parameters + errors + chisquare. One just need to choose well the starting values
> >
> >
> > 90° fits:
> > degrees of freedom (FIT_NDF) : 8
> > rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.419915
> > variance of residuals (reduced chisquare) = WSSR/ndf : 0.176329
> > p-value of the Chisq distribution (FIT_P) : 0.994094
> >
> > Final set of parameters Asymptotic Standard Error
> > ======================= ==========================
> > a = 0.00308376 +/- 0.0005144 (16.68%)
> > c = 15.6259 +/- 2.035 (13.03%)
> > b = 9.36888 +/- 3.16 (33.73%)
> > d = 177.141 +/- 84.95 (47.95%)
> >
> > degrees of freedom (FIT_NDF) : 4
> > rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.283372
> > variance of residuals (reduced chisquare) = WSSR/ndf : 0.0802998
> > p-value of the Chisq distribution (FIT_P) : 0.988405
> >
> > Final set of parameters Asymptotic Standard Error
> > ======================= ==========================
> > m = -6.22672e-06 +/- 1.836e-06 (29.48%)
> > e = 0.00256426 +/- 9.873e-05 (3.85%)
> >
> >
> >
> > 145° fits:
> > degrees of freedom (FIT_NDF) : 6
> > rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.379472
> > variance of residuals (reduced chisquare) = WSSR/ndf : 0.143999
> > p-value of the Chisq distribution (FIT_P) : 0.990247
> >
> > Final set of parameters Asymptotic Standard Error
> > ======================= ==========================
> > a = 0.0012346 +/- 0.0006794 (55.03%)
> > c = 11.3754 +/- 4.075 (35.82%)
> > b = 15.6961 +/- 13.2 (84.1%)
> > d = 116.084 +/- 99.83 (86%)
> >
> > degrees of freedom (FIT_NDF) : 2
> > rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.327728
> > variance of residuals (reduced chisquare) = WSSR/ndf : 0.107405
> > p-value of the Chisq distribution (FIT_P) : 0.898161
> >
> > Final set of parameters Asymptotic Standard Error
> > ======================= ==========================
> > m = -2.39246e-06 +/- 1.278e-06 (53.42%)
> > e = 0.000848859 +/- 7.329e-05 (8.634%)
> >
> >
> >
> > 35° fit:
> > degrees of freedom (FIT_NDF) : 7
> > rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 1.40676
> > variance of residuals (reduced chisquare) = WSSR/ndf : 1.97896
> > p-value of the Chisq distribution (FIT_P) : 0.0538635
> >
> > Final set of parameters Asymptotic Standard Error
> > ======================= ==========================
> > a = 0.000114396 +/- 0.0002367 (206.9%)
> > c = 14.3178 +/- 8.322 (58.13%)
> > b = 16.7454 +/- 43.21 (258%)
> > d = 79.7991 +/- 173.2 (217.1%)
> >
> > degrees of freedom (FIT_NDF) : 3
> > rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 1.21233
> > variance of residuals (reduced chisquare) = WSSR/ndf : 1.46975
> > p-value of the Chisq distribution (FIT_P) : 0.220529
> >
> > Final set of parameters Asymptotic Standard Error
> > ======================= ==========================
> > m = -3.7879e-07 +/- 3.143e-07 (82.99%)
> > e = 7.31447e-05 +/- 1.788e-05 (24.45%)
> >
> >
> >
> > > For the efficiency vs E fit of the 90degree Xray detector I have used the following phenomenological funciton:
> > >
> > > f(x) = a * (1-exp(-(x-c)/b)) * exp(-x/d)
> > >
> > > Here the first exponent member is a saturation curve. This part describes the passing through of the two Be windows (chamber + before detector) and through the dead layer of Ge crystal. One needs a minimum energy to enter to the detecting Ge crystal = C parameter. b parameter = characteristic absorbtion E of these nondetecting layers.
> > > The second exponent is an exponential decrease of the detector efficiency. Photons with higher energy are less detectable by the germaniums. The d parameter is the characteristic E for hard Xray and gamma (>40keV) detectability.
> > >
> > > https://www.amptek.com/internal-products/si-pin-vs-cdte-comparison
> > >
> > > //Jan's comment: the tail of this function should more or less follow a linear trend a bit above than 40 keV.
> > >
> > >
> > > In the attachment there is an example fit for 90 degree with combined 1. and 2. (before and after beamtime) calibration datasets.
> > > I made the fit with gnuplot:
> > >
> > > degrees of freedom (FIT_NDF) : 8
> > > rms of residuals (FIT_STDFIT) = sqrt(WSSR/ndf) : 0.419915
> > > variance of residuals (reduced chisquare) = WSSR/ndf : 0.176329
> > > p-value of the Chisq distribution (FIT_P) : 0.994094
> > >
> > > Final set of parameters Asymptotic Standard Error
> > > ======================= ==========================
> > > a = 0.00308376 +/- 0.0005144 (16.68%)
> > > c = 15.6259 +/- 2.035 (13.03%)
> > > b = 9.36888 +/- 3.16 (33.73%)
> > > d = 177.141 +/- 84.95 (47.95%)
> > >
> > > Laszlo's out. |
|
Tue May 19 16:48:15 2020, Laszlo, General, E127 beamtime overview,
|
Here is a representation how was the time management during E127. The time, what we could spend with measuring the 118Te(pg), was ~20% comparing to the given 6days. |
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