Se170063

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PAA_Selenium/Soil_Experiments#Selenium_Sample_Analysis

Sample Description

The sample was placed in an aluminum cylinder that was to be irradiated. The target components consisted of a nickel foil on the front of the cylinder with 2 pure selenium pellets under the foil, but still outside the cylinder. Inside the target there was burnt sagebrush ash, which was place in an oven, and selenium. Below are the masses of the components

Nickel Foil: 0.2783g

Outer Se Pellets: 0.0971g

Sage Ash: 0.5111g

Inner Se Pellets: 0.0523g

Energy

LB May Calibration 2017

The Calibration for Detector A was done on the morning of 5/23/17 with the MPA software using the thorium rods (as the calibration was fairly close already) and the correction values were found to be Det A Intercept = -12.208800 slope =1.021270


Efficiency

LB May 2017 Det A Efficiency

Nickel Information

Se170063 Nickel Investigation

Activity and Half Life

Se170063 Activity And Half Life


Compare Rates between Two pure SE samples Irradiated at same time and measured using same detector with samples at the same location

Se_5-25-17-RateCompare_OuterSe

Alternative Method

Se170063 Activity and HL Alternate

Corrected Alternative method

The files used for this analysis are in the directory /data/IAC/Se/May2017/5_25_17/Se_Activity_SysOffset_Mix

To begin, I have corrected the mixture to have a factor of 0.62, which is the mystery factor throwing of all of these analyses. The histogram is also weighted by the mass. The weight added to the histogram is

[math] h1 -\gt Fill(evt.Chan,\frac{1}{0.0523*0.62}) [/math]

So the true number of counts has indeed been weighted here. Now I want to try to test every different method that was suggested. So first I am going to weight the mixture by the mystery factor of 0.62, and leave my Gaussian fits as wide as they were previously. The gaussians will probably be made more compact if the mystery factor does not alleviate the problem. The first step is to find the number of counts within the window of interest. Below is the process I used to determine the number of counts and the error associated with it. First begin by plotting the histogram using the ROOT program Eff.C, which is shown below.

170063 Spec Weighted.png

Now take the integral given in the stats box and subtract the background to get the number of counts. Here the number of counts would be

[math] 927800 - 47670 = 880130 Counts [/math]

Now I can convert this error into an activity by dividing by the time, which is 300 seconds in this case. After that take the natural log of the quotient.

[math] \ln{\frac{880130}{300}} = 7.984042428 [/math]

Now to find the error we can notice that the standard deviation here is 0.6238. The procedure is to expand the window by one or two standard deviations and find the difference in the number of counts in the original window. Due to the binning here I have decided to expand the window by 1 channel on each side, which is roughly 2 standard deviations. A picture is given below.

170063 Spec ExpandedWindow.png

Now we do a similar method to find the number of counts within this window.

[math] 1017000 - 46810 = 970190 Counts [/math]

Now take the difference between the original window's number of counts and the expanded window's number of counts.

[math] 970190 - 880130 = 90060 Counts [/math]

Now to propagate this error we must divide this number by the original number of counts.

[math] \frac{90060}{880130} = 0.1023257928 [/math]

This method was repeated for the next set of runs that make the data file. The numbers are in a table below.

0 <t< 300 sec 730 < t < 1020 sec 1480 < t < 1775 2250 < t < 2550 sec 3050 < t < 3300 sec 3775 < t < 4050 sec 4480 < t < 4770 sec
Original Window Counts 880200 716200 617100 545800 394100 362000 346300
Original Window Background (Integrated) 381379 267608 215260 189665 143921 137541 128197
Original Window Difference 498821 448592 401850 356135 250179 224459 218103
Expanded Window Counts 970900 782600 671300 593100 426700 395400 378100
Expanded Window Background 468138 333633 269025 236476 173353 170089 159644
Expanded Window Difference 502762 448967 402275 356624 253347 225311 218456
Error in counts 3941 375 425 489 3168 852 353
.dat file entry 7.416220118 +/- 0.0079006297 7.343988145 +/- 0.0008359489264 7.216858801 +/- 0.0010576086 7.079282677 +/- 0.0013730748 6.908471023 +/- 0.012662933 6.704677244 +/- 0.0037957934 6.622841784 +/- 0.0016185014

Below is the graph that contains the information about the initial activity and the half life

170063 WindowExpand WideGauss HLPlot.png

The slope of the line is -0.00019198 +/- 4.13511e^-7, which gives a half life of

[math] t_{\frac{1}{2}} = \frac{\ln{2}}{\lambda}\rightarrow 60.18 minutes [/math]

While the error is

[math] \sigma_{t_{\frac{1}{2}}} = \frac{\ln{2}*\sigma_{\lambda}}{\lambda^2} \rightarrow 0.13 minutes [/math]

The constant value given by the plot is 7.4918 +/- 0.000927611, which gives an initial activity of

[math] A_0 = e^{7.4918} = 1793.28 Hz [/math]

and an error of

[math] e^{7.4918}*\sigma_{A} = 1.66 Hz [/math]

Now correcting for the efficiency we have

[math] A_0^' = \frac{A_0}{\epsilon} = \frac{1793.28}{0.007} = 256182.8571 Hz [/math]

While the error is

[math] \sigma_{A_0^'} = \frac{A_0}{\epsilon^2}*\sigma_{\epsilon} = 402.57 Hz [/math]

Below are the related pages for this sample using this method of window expansion:

Se170063 Nickel Foil Wide Gauss Window Expansion

Se170063 Pure Se Wide Gauss Window Expansion

Runlist

Table with dates and filename and locations on daq1

LB_May_2017_Irradiation_Day#10.25_Se_Soil_Mix

PAA_Selenium/Soil_Experiments#Selenium_Sample_Analysis