Difference between revisions of "PAA Selenium"

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=Can one use plant material to measure the provenance of selenium?=
 
=Can one use plant material to measure the provenance of selenium?=
  
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[[Se_Overview_PrevMeas]]
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 +
As shown in the Figure below, the Se-82/Se-76 ratio varies from -1.2% to +0.2% for plant materials but remains relatively constant for other materials.  The variations in plant material has been described as being due to differences in the bacteria residing in the plant.  The question to investigate is whether or not these variations in the concentration can be used to determine the provenance of the sample.
 +
 +
 +
 +
 +
[[File:Krouse_Fig_1.png | 200 px]]
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 +
== Below is a table listing the natural abundances of Selenium==
 
Natural abundance of selenium
 
Natural abundance of selenium
  
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|}
 
|}
  
Possible reactions
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== Below are possible PAA reactions that may be used to observe specific Se isotopes==
  
 
  {| border="3"  cellpadding="5" cellspacing="0"
 
  {| border="3"  cellpadding="5" cellspacing="0"
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=Can one perform PAA measurements of Se-82 and Se-76?=
 
=Can one perform PAA measurements of Se-82 and Se-76?=
  
 
+
[[Se_PAA_Reactions]]
==Neutron knockout of Se-82==
 
If you knock a neutron out of Se-82 you produce the unstable isotope Se-81 which Beta emitts with half life of 18 min and a meta-state that emmits a 103 keV gamma with a 57 minute half life.
 
 
 
<math>{82 \atop 34\; }Se (\gamma,n){81 \atop \; }Se</math>
 
 
 
Other prominent photons
 
 
 
260 & 276 keV for the 57 minute half life isotope
 
 
 
==Neutron knockout of Se-76==
 
If you knock a neutron out of Se-76 you produce the unstable isotope Se-75 which has a half life of 119 days.
 
 
 
<math>{76 \atop\; }Se (\gamma,n){75 \atop \; }Se</math>
 
 
 
The prominent photons emitted have the following energies
 
 
 
136, 264, and 279 keV
 
 
 
 
 
The article below describes how plant material and soil contain Se-76 to Se-82 ratios that differ from other natural samples by 1.5%.  They argue that it is due to the bacteria living in plant material. 
 
 
 
[[File:Krouse_CanJournChem_40_1962_p367.pdf]]
 
 
 
Plant material is a natural way to sample the selenium content to determine if there are difference isotopic ratios due to the impact of human activities on the environment.
 
 
 
 
 
==Relative Yield Calculations==
 
For this section, I am interested in finding the relative yield of Se-79 when compared to Se-81 and Se-75. Cross sections were found at this website: http://www-nds.indcentre.org.in/exfor/servlet/X4sSearch5?EntryID=220070
 
 
 
===Cross-section===
 
 
 
Below is a sample table of the cross section of a <math>{80 \atop 34\; }Se (\gamma,n){79 \atop \; }Se</math> reaction.  The beta endpoint for this long lived isotope is 150 keV with the highest intensity photon lines at 11 keV.
 
 
 
{| border="3"  cellpadding="5" cellspacing="0"
 
|| Energy (MeV) || Cross Section( millibarns) || ** || Energy (MeV) || Cross Section (millibarns) || ** || Energy (MeV) || Cross Section (millibarns) 
 
|-
 
|| 10.02 || 7.1 +/- 0.2 || ** || 15.02 || 110.9 +/- 4.6 || ** || 20.02 || 83 +/- 5.7
 
|-
 
||10.22 || 10.3 +/- 0.4 || ** || 15.22 || 118.9 +/- 4.1 || ** || 20.22 || 79.9 +/- 6.2
 
|-
 
||10.42|| 12.9 +/- 0.5 || ** || 15.42 || 125.8 +/- 5.5 || ** || 20.42 || 67.1 +/- 7.2
 
|-
 
||10.62||  16.2 +/- 0.5 || ** || 15.62 || 132.9 +/- 4.5 || ** || 20.62 || 70.9 +/- 6.6
 
|-
 
||10.82|| 19.2 +/- 0.6 || ** || 15.82 || 132.7 +/- 5.9 || ** || 20.82 || 72.2 +/- 7.6
 
|-
 
||11.02|| 22 +/- 0.6 || ** || 16.02 || 127.6 +/- 5.6 || ** || 21.02 || 66.8 +/- 6.5
 
|-
 
||11.22||23.8 +/- 1 || ** || 16.22 || 132.4 +/- 5.3 || ** || 21.22 || 69.7 +/- 7
 
|-
 
||11.42||28 +/- 1 || ** || 16.42 || 130 +/- 7.6 || ** || 21.42 || 68.2 +/- 8.4
 
|-
 
||11.62|| 28.6 +/- 1.2 || ** || 16.62 || 125.4 +/- 6.2 || ** || 21.62 || 68.6 +/- 7.4
 
|-
 
||11.82|| 30.4 +/- 1.5 || ** || 16.82 || 137.4 +/- 6.7 || ** || 21.82 || 60.9 +/- 7.3
 
|-
 
||12.02|| 33 +/- 1.4 || ** || 17.02 || 138.1 +/- 7.5 || ** || 22.02 || 58.5 +/- 7.3
 
|-
 
||12.22|| 34.9 +/- 1.8 || ** || 17.22 || 130.4 +/- 8.3 || ** || 22.22 || 56 +/- 7.8
 
|-
 
||12.42|| 37.6 +/- 1.4 || ** || 17.42 || 114.9 +/- 6 || ** || 22.42 || 69.7 +/- 7.7
 
|-
 
||12.62|| 41.5 +/- 2 || ** || 17.62 || 110.8 +/- 6 || ** || 22.62 || 60.1 +/- 8.8
 
|-
 
||12.82|| 43.6 +/- 2.5 || ** || 17.82 || 104.4 +/- 7.4 || ** || 22.82 || 60.9 +/- 8.7
 
|-
 
||13.02||46.7 +/- 2.8 || ** || 18.02 || 108.7 +/- 6.6 || ** || 23.02 || 58.8 +/- 9.3
 
|-
 
||13.22||51.9 +/- 2.6 || ** || 18.22 || 102.4 +/- 7.3 || ** || 23.22 || 50.6 +/- 9.7
 
|-
 
||13.42||56.7 +/- 1.5 || ** || 18.42 || 104.3 +/- 5.7 || ** || 23.42 || 31.5 +/- 8.7
 
|-
 
||13.62|| 61.4 +/- 2.9 || ** || 18.62 || 104.1 +/- 5.5 || ** || 23.62 || 37.7 +/- 8.7
 
|-
 
||13.82|| 69.5 +/- 3.3 || ** || 18.82 || 91.1 +/- 7.8 || ** || 23.82 || 29.5 +/- 10.2
 
|-
 
||14.02||78.7 +/- 4.4 || ** || 19.02 || 90.5 +/- 5.5 || ** || 24.02 || 32.4 +/- 8.6
 
|-
 
||14.22||84.9 +/- 3.6 || ** || 19.22 || 85.7 +/- 6.2 || ** || 24.22 || 32.8 +/- 9.6
 
|-
 
||14.42|| 93.3 +/- 2.7 || ** || 19.42 || 91.4 +/- 6.6
 
|-
 
||14.62|| 100.5 +/- 4 || ** || 19.62 || 84.9 +/- 5.6
 
|-
 
||14.82|| 105.1 +/- 4.6 || ** || 19.82 || 90.3 +/- 8.1
 
|}
 
 
 
Similar data can be found in the link above. Below is the plot for all the reactions of interest.
 
 
 
Below is a plot of 3 different isotopes of selenium with their cross sections as a function of energy.
 
 
 
[[File:PhotonE vs XSect.png|200px]]
 
 
 
Now to find the relative yields, I approximated the integral the above graph using a left hand Riemann sum with an interval width of 1 MeV and multiplied it by the natural abundance in the sample. Below is a table of the reactions and their integrated cross sections.
 
 
 
 
{| border="3"  cellpadding="5" cellspacing="0"
 
|| Reaction || Abundance || Integrated Cross Section (Mev * mb)
 
|-
 
|| Se-82(gamma,n)Se-81 || 8.82% || 1102.9
 
|-
 
|| Se-80(gamma,n)Se-79 || 49.8% || 1062.8
 
|-
 
|| Se-76(gamma,n)Se-75 || 9.23% || 836.5
 
|}
 
 
 
Below are the equations for the relative yield of each isotope.
 
 
 
 
 
<math>\frac{{76 \atop 34\; }Se (\gamma,n){75 \atop \;Se}}{{80 \atop 34\; }Se (\gamma,n){79 \atop \;Se}} = \frac{Abundance \times \int_{10.02}^{24.02}\sigma dE}{Abundance \times \int_{10.02}^{24.02}\sigma dE} = \frac{0.0923 \times 836.5}{0.498 \times 1062.8} = 0.15</math>
 
 
 
 
 
<math>\frac{{82 \atop 34\; }Se (\gamma,n){81 \atop \;Se}}{{80 \atop 34\; }Se (\gamma,n){79 \atop \;Se}} = \frac{Abundance \times \int_{10.02}^{24.02}\sigma dE}{Abundance \times \int_{10.02}^{24.02}\sigma dE} = \frac{0.0882 \times 1102.9}{0.498 \times 1062.8} = 0.18</math>
 
 
 
===Activity Productions===
 
 
 
 
 
Let
 
 
 
;<math>N(t)</math> = The number of activated atoms per cubic cm
 
;<math>\mathcal{N}</math> =The number density of the target
 
;<math> \phi</math> = incident photon flux ( photons/sec/cm/cm)
 
  
 
=Experiments=
 
=Experiments=
  
==Chlorine==
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==[[PAA_Selenium_ActivityCalc]]==
 
 
It looks like Cl-35 is abundant as you see photon energies of 146 keV and 2127 keV (you can barely see 1176 keV) from Cl-34's decay (neutron knocked out of Cl-35).
 
 
 
The half life is 32 minutes.
 
 
 
Should check the half life from the run AccOnAlInDetASe-AinDetD_001.root using the calibration
 
 
 
MPA->Draw("0.18063+0.960133*evt.Chan>> SeRun_008(8000,0.5,8000.5)","evt.ADCid==3");
 
 
 
== Irradiation of Horse Mineral Supplement==
 
 
 
Below is the EMSL report for the horse feed sample.
 
https://wiki.iac.isu.edu/index.php/File:EMSL_Report_Horse_Feed.pdf
 
 
 
=== Chlorine is a dominant signal===
 
 
 
 
 
First, look at the peak around 146 keV
 
[[File:146_keV.png | 200 px]]
 
 
 
Next I plotted the counts as a function of time to get an exponentially decaying graph. When doing an exponential fit here, the parameter "b" given by root will be the decay constant.
 
 
 
[[ File:Chlorine.png | 200 px]]
 
 
 
Root gives a half life of 32.9508 +/- 0.01 minutes
 
 
 
 
 
Now do the same for the 2127 keV line
 
[[File:2127_keV.png | 200 px]]
 
 
 
Here are the counts plotted as a function of time
 
[[File:2127.png | 200 px ]]
 
 
 
Root gives a half life of 35.3962 +/- 0.2 minutes
 
 
 
=== Potassium is a potential signal ===
 
 
 
Looking at the spectrum for the fast irradiation sample, there are 2 prominent lines that could be from 38-K. The mechanism would be a single neutron knockout from a stable 39-K nucleus. The two most dominant energies of the three for 38-K are 2167 keV and 3936 keV and the half life is 7.63 minutes. Below is a fit to the energy spectrum histogram
 
 
 
[[File:2168_peak.png | 200 px]]
 
 
 
Now check the half life
 
 
 
 
 
[[File:2167.png | 200 px]]
 
 
 
Root gives a half life of 8.03 +/- 0.02 minutes
 
 
 
Next check the 3936 peak
 
 
 
[[File: 3937_Peak.png | 200 px ]]
 
  
and check the half life
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[[PAA Selenium/Soil Experiments]]
  
[[File: 3936_keV_halflife.png | 200 px ]]
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[[LB Se PAA Horse Feed Experiment]]
  
Root gives a value for b = - 1.14372x10^(-3), which in turn gives a half life of 10.1 minutes
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==Background Signals==
 +
[[PAA_BackGrd_Det_A]]
  
It seems very possible that 38-K could be in the sample of horse feed.
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==Nickel Normalization==
 +
[[LB PAA Nickel Investigation]]
  
 
== First Observation of Se lines==
 
== First Observation of Se lines==
Line 252: Line 91:
  
 
== MDA and Se mass Calculations ==
 
== MDA and Se mass Calculations ==
To find the mass of the selenium in the irradiated horse feed sample, we need some masses and volumes of the horse feed. A vial containing 20mL of regular horse feed was massed. The mass of the vial was 13.6406g and the total mass of the vial and the horse feed was 31.8504g. This means the mass of the horse feed is <math>31.8504g - 13.6406g = 18.2098g</math>. Since this mass is in a 20mL = 0.02L container, the density of the horse feed (assuming the mass difference between the non-irradiated and the irradiated horse feed is negligible) is
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[[LB MDA/Se Mass Calculations]]
  
<math>\frac{18.2098g}{0.02L} = 910.49 \frac{g}{L}</math>.
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==IAC Detector Efficiencies ==
  
Now for the irradiated horse feed the mass of the container is 25.0259g and the total mass of the container and the sample is 43.7529g. The mass of the sample then is 43.7529g - 25.0259g = 18.727g. Now using the density found before we can find the volume of the irradiated horse feed within the container.
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[[LB PAA IAC Detector Efficiencies]]
  
<math>\rho = 910.49\frac{g}{L} = \frac{18.727}{V},  V = \frac{18.727g}{910.49 \frac {g}{L}} = 0.0206L.</math>
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==IAC Detector Calibrations==
  
The EMSL report says that there are <math>0.56\frac{mg}{L}</math> in the horse feed, so the mass of the selenium in the horse feed sample is
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[[LB April DetB DetA Calibration]]
  
<math>0.56\frac{mg}{L}\times 0.0206L = 0.011536mg</math>.
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==Runlists==
 +
[[LB PAA Runlist 4/01/16 - 06/02/16]]
  
 +
[[LB March 2017 Runlist]]
  
 +
[[LB_May_2017_Irradiation_Day]]
  
Each of the calibration runs were used at position C in detector D. Below is the runlist for the isotopes used. The intervals used were (117:127) and (272:282) respectively.
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=Data Analysis=
  
{| border="3"  cellpadding="5" cellspacing="0"
 
|  Source || Serial # || Reference Date || Activity || Start || Stop || Live 
 
|-
 
| Co-57 || 129735 || 07/01/08 || 1.074 micro Ci || 16:17:37 || 16:27 || 601.10
 
|-
 
| Ba-133 || 129790 || 07/01/08 || 1.188 micro Ci || 16:29:14 || 16:32 || 208.259
 
|-
 
|}
 
  
For the Co-57, the activity as of 09/07/16 is 0.0005 microCi and the intensity of the 122.3 keV line is 85.6%
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[[LB_Feb2017_Se_Investigations]]
:= <math>\left (0.856 \right )\left ( 0.0005 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)= 15.84 Hz </math> for the 122.3 line
 
  
 +
=References=
  
For the Ba-133, the activity as of 09/07/16 is 0.69 microCi and the intensity of the 277.05 keV line is 7.164%
 
:= <math>\left (0.07164 \right )\left ( 0.69 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)= 1828.97 Hz </math> for the 277.05 line
 
  
 +
[[User_talk:Brenleyt]]
  
{| border="3"  cellpadding="5" cellspacing="0"
 
|  Run || Source || Energy (keV) || Expected Rate (Hz) || HpGe Rate (Hz) || HpGe Det D Efficiency (%) 
 
|-
 
| Eff_C_Co_57.root || Co-57 || 122.3 || 15.84 || 0.4526 - 0.2144 || 1.5
 
|-
 
|Eff_C_Ba_133.root || Ba-133 || 277.05 || 1828.97 || 20.58 - 0.07641 || 1.12
 
|}
 
  
Now that the efficiency has been found, we must find the background rate to find the MDA. To find the background rate I used ROOT and plotted the energy spectra for Se_B_005 and HorseFeed_NoIrr. The windows of interest are the same as above. Each run's time was cut down to 1 hour.
+
<references/>
  
First I will find the MDA for the window from (117:127). In Se_B_005, the activity was found to be 0.8433 HZ and in the HorseFeed_NoIrr the activity was found to be 0.2133 Hz, which gives a background rate of 0.63 Hz -> 37.6 cpm.
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[[File:Krouse_CanJournChem_40_1962_p367.pdf]]
  
Now we can compute the MDA using this reference https://wiki.iac.isu.edu/index.php/File:Nwsltr-43re.pdf
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Goryachev, A. M., & Zalesnyy, G. N. (n.d.). The studying of the photoneutron reactions cross sections in the region of the giant dipole resonance in zinc, germanium, selenium, and strontium isotopes. Retrieved September 16, 2016, from http://www-nds.indcentre.org.in/exfor/servlet/X4sSearch5?EntryID=220070
 
 
I found the MDA to be [(2.71 + 4.65*(37.6 * 60)^1/2]/(60*0.015) = 249.1 dpm
 
 
 
Now I will find the MDA for the window from (272:282). In Se_B_005, the activity was found to be 0.7408 Hz and in HorseFeed_NoIrr the activity was found to be 0.08278. This means that the background activity is 0.66 Hz -> 39.48 cpm.
 
 
 
Now we can compute the MDA = [(2.71 + 4.65*(39.48 * 60)^1/2]/(60*0.012) = 318.1 dpm
 
  
== Detector Efficiency ==
+
Goryachev, B. I., Ishkhanov, B. S., Kapitonov, I. M., Piskarev, I. M., Piskarev, V. G., & Piskarev, O. P. (n.d.). Giant Dipole Resonance on Ni Isotopes. Retrieved October 26, 2016, from http://www-nds.indcentre.org.in/exfor/servlet/X4sGetSubent?reqx=119235&subID=220597006&plus=1
  
Below is the runlist for finding the efficiency of the detector at position R
 
  
  
{| border="3"  cellpadding="5" cellspacing="0"
+
Handbook on Photonuclear data for applications, cross sections, and spectra. (2000, October). Retrieved November 4, 2016, from http://www-pub.iaea.org/MTCD/Publications/PDF/te_1178_prn.pdf
|  Source || Serial # || Reference Date || Activity || Start || Stop || Live 
 
|-
 
| Na-22  || 129743 || 7-01-08 || 9.427 microCi || 15:49 || 16:19 || 1796.803 
 
|-
 
| Cs-137 || 129793 || 7-01-08 || 1.006 microCi || 14:25 || 14:56 || 1879.606
 
|-
 
| Mn-54 || 129807 || 7-01-08 || 11.77 microCi || 15:00 || 15:30 || 1793.420
 
|-
 
| Co-60 || 129740 || 7-01-08 || 10.42 microCi || 15:33 || 15:43 || 569.725
 
|-
 
|}
 
 
 
Below are the theoretical calculations for the theoretical decay frequencies
 
 
 
Na-22, 9.427micro Ci on July 1, 2008, half life 2.602 +/- 0.002 years, 99.937% for 1274.52 and 178.8 for 511 line , activity in March 31, 2016 =1.196micro Ci
 
:= <math>\left (0.99937 \right )\left ( 1.196 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)= 44,224 Hz </math> for the 1274 line
 
 
 
:= <math>\left (1.788 \right )\left ( 1.196 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)=  79122.6 Hz </math> for the 511 line
 
 
 
Cs-137, 661.660 line, 85.21% * 1.066micro Ci on July 1, 2008, half life 30.0 +/- 0.2 yrs, March 31, 2016 activity = 0.891micro Ci expected rate for 661 line
 
 
 
:= <math>\left (0.8521 \right )\left ( 0.891 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)= 28091.2 Hz </math>
 
 
 
Mn-54, 11.77 microCi  on July 1, 2008, half life =312.20 +/- 0.07 days, 99.975% intensity on 834.826 , March 31, 2016 activity =0.02328micro Ci
 
 
 
:= <math>\left (0.99975 \right )\left ( 0.02328 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)=  861.1 Hz </math> for the 834 line
 
 
 
 
 
Co-60, 10.42micro Ci July 1, 2008, half life 5.271 +/- 0.001 years, 99.0 % for 1173.237 and 99.9824 % for 1332.501, March 31, 2016 activity=3.759micro Ci
 
 
 
 
 
:= <math>\left (0.99 \right )\left ( 3.759 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)=  137692.17 Hz </math> for the 1173 line
 
 
 
 
 
:= <math>\left (0.999824 \right )\left ( 3.759 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)=  139058.52 Hz </math> for the 1332 line
 
 
 
 
 
Below is a table where the actual efficiency will be calculated for position R (farthest position).
 
 
 
{| border="3"  cellpadding="5" cellspacing="0"
 
|  Run || Source || Energy (keV) || Expected Rate (Hz) || HpGe Rate (Hz) || HpGe Det D Efficiency (%) 
 
|-
 
| Eff_003  || Na-22 || 511 || 79122.6 || (506:516) (4.309-0.065=4.244) || 0.005
 
|-
 
| Eff_005 || Cs-137 || 661.657 || 28091.2 ||(657:666)(1.105-0.02281=1.0821) ||0.004
 
|-
 
| Eff_006 || Mn-54 || 834.848  || 861.1 ||(830:839)(0.04037-0.009123=0.031247)||0.004
 
|-
 
| Eff_007 || Co-60 ||  1173.228 || 137692 ||(1164:1182)(3.686-0.01939=3.67)||0.003
 
|-
 
| Eff_003 || Na-22 || 1274.537 || 44224 ||(1270:1279) (1.073-0.0057=1.0673)||0.002
 
|-
 
| Eff_007 || Co-60 ||  1332.492 || 139058.52 ||(1328:1337)(3.283-0.05702=3.22598)|| 0.002
 
|}
 
 
 
Below is a runlist for position k
 
 
 
{| border="3"  cellpadding="5" cellspacing="0"
 
|  Source || Serial # || Reference Date || Activity || Start || Stop || Live 
 
|-
 
| Na-22  || 129743 || 7-01-08 || 9.427 microCi || 14:54 || 15:01 || 434.087 
 
|-
 
| Cs-137 || 129793 || 7-01-08 || 1.006 microCi || 15:48 || 15:55 || 413.925
 
|-
 
| Mn-54 || 129807 || 7-01-08 || 11.77 microCi || 15:28 || 15:40 || 705.186
 
|-
 
| Co-60 || 129740 || 7-01-08 || 10.42 microCi || 15:41 || 15:47 || 346.092
 
|-
 
|}
 
 
 
Below are the theoretical decay frequencies
 
 
 
Na-22, 9.427micro Ci on July 1, 2008, half life 2.602 +/- 0.002 years, 99.937% for 1274.52 and 178.8 for 511 line , activity in April 14, 2016 =1.183micro Ci
 
:= <math>\left (0.99937 \right )\left ( 1.183 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)= 43743.4 Hz </math> for the 1274 line
 
 
 
:= <math>\left (1.788 \right )\left ( 1.183 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)= 78262.5  Hz </math> for the 511 line
 
 
 
Cs-137, 661.660 line, 85.21% * 1.066micro Ci on July 1, 2008, half life 30.0 +/- 0.2 yrs, April 14, 2016 activity =0.890 micro Ci expected rate for 661 line
 
 
 
:= <math>\left (0.8521 \right )\left ( 0.890 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)= 28059.7 Hz </math>
 
 
 
Mn-54, 11.77 on July 1, 2008, half life =312.20 +/- 0.07 days, 99.975% intensity on 834.826 , April 14, 2016 activity =0.02251micro Ci
 
 
 
:= <math>\left (0.99975 \right )\left ( 0.02251 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)=  830.79 Hz </math> for the 834 line
 
 
 
 
 
Co-60, 10.42micro Ci July 1, 2008, half life 5.271 +/- 0.001 years, 99.0 % for 1173.237 and 99.9824 % for 1332.501, April 14, 2016 activity=3.74micro Ci
 
 
 
 
 
:= <math>\left (0.99 \right )\left ( 3.74 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)=  136996.2 Hz </math> for the 1173 line
 
 
 
 
 
:= <math>\left (0.999824 \right )\left ( 3.74 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)=  138355.6 Hz </math> for the 1332 line
 
 
 
Below are the actual efficiencies for position k
 
 
 
{| border="3"  cellpadding="5" cellspacing="0"
 
|  Run || Source || Energy (keV) || Expected Rate (Hz) || HpGe Rate (Hz) || HpGe Det D Efficiency (%) 
 
|-
 
| Eff_k_002  || Na-22 || 511 || 79122.6 || (506:516)(49.21-0.6272=48.58) || 0.06
 
|-
 
| Eff_k_006 || Cs-137 || 661.657 || 28091.2 ||(657:666)(12.86-0.02281=12.837) ||0.05
 
|-
 
| Eff_k_004 || Mn-54 || 834.848  || 861.1 ||(830:839)(0.3204-0.009123=0.311)||0.04
 
|-
 
| Eff_k_005 || Co-60 ||  1173.228 || 137692 ||(1164:1182)(42.39-0.02053=42.369)||0.03
 
|-
 
| Eff_k_002 || Na-22 || 1274.537 || 44224 ||(1270:1279) (12.53-0.005702)=12.52||0.03
 
|-
 
| Eff_k_005 || Co-60 ||  1332.492 || 139058.52 ||(1328:1337)(35.94-0.005072)|| 0.03
 
|}
 
 
 
Below is a runlist for position C
 
 
 
{| border="3"  cellpadding="5" cellspacing="0"
 
|  Source || Serial # || Reference Date || Activity || Start || Stop || Live 
 
|-
 
| Na-22  || 129742 || 7-01-08 || 1.146 microCi || 12:55 || 12:57 || 129.782 
 
|-
 
| Cs-137 || 129793 || 7-01-08 || 1.006 microCi || 13:02 || 13:04 || 123.818
 
|-
 
| Mn-54 || 129806 || 7-01-08 || 1.226 microCi || 13:11 || 13:21 || 613.754
 
|-
 
| Co-60 || 129739 || 7-01-08 || 1.082 microCi || 13:08 || 13:09 || 103.599
 
|-
 
|}
 
 
 
Below are the calculations for the theoretical frequencies
 
 
 
Na-22, 9.427micro Ci on July 1, 2008, half life 2.602 +/- 0.002 years, 99.937% for 1274.52 and 178.8 for 511 line , activity in May 5, 2016 =1.196micro Ci
 
:= <math>\left (0.99937 \right )\left ( 0.14 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)= 5176.7 Hz </math> for the 1274 line
 
 
 
:= <math>\left (1.788 \right )\left ( 0.14 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)=  9261.8 Hz </math> for the 511 line
 
 
 
Cs-137, 661.660 line, 85.21% * 1.066micro Ci on July 1, 2008, half life 30.0 +/- 0.2 yrs, May 5, 2016 activity = 0.89micro Ci expected rate for 661 line
 
 
 
:= <math>\left (0.8521 \right )\left ( 0.891 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)= 28059.7 Hz </math>
 
 
 
Mn-54, 1.226 microCi on July 1, 2008, half life =312.20 +/- 0.07 days, 99.975% intensity on 834.826 , May 5, 2016 activity =0.002micro Ci
 
 
 
:= <math>\left (0.99975 \right )\left ( 0.002 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)=  73.98 Hz </math> for the 834 line
 
 
 
 
 
Co-60, 1.082micro Ci July 1, 2008, half life 5.271 +/- 0.001 years, 99.0 % for 1173.237 and 99.9824 % for 1332.501, May 5, 2016 activity=0.39micro Ci
 
 
 
 
 
:= <math>\left (0.99 \right )\left ( 0.39 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)=  14285.7 Hz </math> for the 1173 line
 
 
 
 
 
:= <math>\left (0.999824 \right )\left ( 0.39 \times 10^{-6} \mbox{Ci} \right) \left (\frac{ (3.7 \times 10^{10} \mbox{Hz}}{\mbox{Ci}} \right)=  14427.5 Hz </math> for the 1332 line
 
 
 
Below is a table with the calculated efficiencies
 
 
 
{| border="3"  cellpadding="5" cellspacing="0"
 
|  Run || Source || Energy (keV) || Expected Rate (Hz) || HpGe Rate (Hz) || HpGe Det D Efficiency (%) 
 
|-
 
| Eff_C_001  || Na-22 || 511 || 9261.8 || (506:516) (45.65-0.065=45.585) || 0.5
 
|-
 
| Eff_C_002 || Cs-137 || 661.657 || 28059.7 ||(657:666)(101.7-0.02281=101.67) || 0.4
 
|-
 
| Eff_C_004 || Mn-54 || 834.848  || 73.98 ||(830:839)(0.2704-0.009123=0.2612)||0.4
 
|-
 
| Eff_C_003 || Co-60 ||  1173 || 14285.7 ||(1164:1182)(34.24-0.01939=34.22)||0.2
 
|-
 
| Eff_C_001 || Na-22 || 1274.537 || 5176.7 ||(1270:1279) (11.15-0.0057=11.14)||0.2
 
|-
 
| Eff_C_003 || Co-60 ||  1332.492 || 14427.5 ||(1328:1337)(28.05-0.05702=27.99)|| 0.2
 
|}
 
 
 
=Run List=
 
 
 
{| border="3"  cellpadding="5" cellspacing="0"
 
|  Date || Time elapsed (Seconds) || Sample || Document Title || Start || Stop || Real || Live || Position 
 
|-
 
| 04-01-16  || 2.16x10^6 || Se_B || Se_B_002 || 15:55 || 09:15 || 235989.882 || 235687.660 || k
 
|-
 
| 04-06-16 || 2.592x10^6 || Se_B || Se_B_003 || 12:57 || Interrupted || computer || crash || k
 
|-
 
| 04-14-16 || 3.283x10^6 || Se_B  || Se_B_005 || 15:57 || 09:37 || 63581.784 || 63509.895||k
 
|-
 
| 04-15-16 || 3.37x10^6 ||  Sample D || Sample_D_001 || 14:47 || 08:23 || 236172.264 || 236173.271||k
 
|-
 
| 04-19-16 || 3.715x10^6 || Sample B || Sample_B_001 ||15:31||15:18 || 85634.862 || 85624.090||k
 
|-
 
| 4-20-16 || 3.802x10^6 ||  Sample C || Sample_C_001 ||15:22||10:19 || 68253.774 || 68232.238||k
 
|-
 
| 04-21-16 || 3.888x10^6 || Sample A || Sample_A_001 || 10:22 || 10:37 || 87292.409 || 87268.114||k
 
|-
 
|04-25-16 || 4.234x10^6 || Sample E || Sample_E_001 || 11:36 || 10:03 || 80822.406 || 80795.679||k
 
|-
 
|04-26-16 || 4.32x10^6 || Se_B || Se_B_008 || 10:06 || 10:29 || 87784.755 || 87664.070 || k
 
|-
 
|05-05-16 || 5.098x10^6 || Sample A || Sample_A_002 || 13:31 || 14:30 || 3605.507 || 3602.925 || c
 
|-
 
|05-05-16 || 5.098x10^6 || Sample B || Sample_B_002 || 14:34 || 15:26 || 3114.244 || 3112.620 || c
 
|-
 
|05-05-16 || 5.098x10^6 || Sample C || Sample_C_002 || 15:28 || 10:57 || 70124.788 || 70044.470 || c
 
|-
 
| 05-06-16 ||5.184x10^6|| Sample D || Sample_D_002 || 10:59 || 15:34 || 16516.898 || 16512.570||c
 
|-
 
|05-06-16 || 5.184x10^6 || Sample E || Sample_E_004 || 15:37 || 16:18 || 261654.225 || 261344.308 || c
 
|-
 
|05-09-16 || 5.443x10^6 || Se B|| Se_B_012 || 16:20 || 11:08||67157.101||66660.298 || c
 
|-
 
|05-10-16 || 5.5296x10^6 || Sample A || Sample_A_004 || 11:03 || 15:19 || 15379.475 || 15363.017 || c
 
|-
 
|05-10-16 || 5.5296x10^6 || Sample B || Sample_B_004 || 15:22:04 || 11:43 || 73256.181 || 73220.324 || c
 
|-
 
|05-16-16 || 6.048x10^6 || Sample C || Sample_C_004 || 16:33 || 08:19 || 56758.980 || 56711.121 || c
 
|-
 
|05-18-16 || 6.2208x10^6 || Sample D || Sample_D_006 || 08:44:21 || 14:05 || 19271.829 || 19266.929 || c
 
|-
 
|05-18-16 || 6.2208x10^6 || Sample E || Sample_E_006 || 14:08 || 08:06 || 151108.258 || 150955.915 || c
 
|-
 
|05-20-16 || 6.3936x10^6 || Se_B || Se_B_014 || 08:08:47 || 08:44 || 261353.204 || 259621.655 || c
 
|-
 
|05-23-16 || 6.6528x10^6 || Sample A || Sample_A_006 || 08:48 || 13:49 || 18103.004 || 18091.523 || c
 
|-
 
|05-23-16 || 6.6528x10^6 || Sample B || Sample_B_006 || 13:52 || 13:24 || 84763.938 || 84696.083 || c
 
|-
 
|05-24-16 || 6.7392x10^6 || Sample C || Sample_C_006 || 13:28:28 || 10:28 || 75571.716 || 75502.871 || c
 
|-
 
|05-31-16 || 7.344x10^6 || Sample B || Sample_B_008 || 08:57:22 || 08:55 || 86282.861 || 86237.392 || c
 
|-
 
|06-01-16 || 7.4304x10^6 || Sample C || Sample_C_008 || 08:58:39 || 13:31 || 102739.504 || 102647.471 || c
 
|-
 
|06-02-16 || 7.5168x10^6 || Sample D || Sample_D_010 || 13:33 || 08:41 || 68915.044 || 68898.246 || c
 
|}
 
 
 
[[SeRun_01-11-16]]
 
 
 
[[SeRun_03-07-16]]
 
 
 
=References=
 
 
 
<references/>
 
 
 
[[File:Krouse_CanJournChem_40_1962_p367.pdf]]
 
 
 
Goryachev, A. M., & Zalesnyy, G. N. (n.d.). The studying of the photoneutron reactions cross sections in the region of the giant dipole resonance in zinc, germanium, selenium, and strontium isotopes. Retrieved September 16, 2016, from http://www-nds.indcentre.org.in/exfor/servlet/X4sSearch5?EntryID=220070
 
  
 
=MSDS=
 
=MSDS=

Latest revision as of 22:10, 17 May 2019

Using PAA ro measure Selenium concentrations.

According to Krouse<ref name="Krous1962"> H.R. Krause and H.G. Thode,"Thermodynamic Properties and Geochemistry of Iosotopic Compounds of Selenium",.Can. J. Chem., vol 40, pg 367</ref> , the fractional concentration of Se-82/Se-76 in plant material is observed to be less than from primordial (meteoric) concentrations by as much as 1.2%. Anaerobic bacteria are known to reduce selenates and senelites in biological systems. This may be the reason plant material has fractionation of selenium isotopes. They also observe excess concentrations of up to 0.4% in soil.


Plant material appears to detect environmental selenium.

Can one use plant material to measure the provenance of selenium?

Se_Overview_PrevMeas

As shown in the Figure below, the Se-82/Se-76 ratio varies from -1.2% to +0.2% for plant materials but remains relatively constant for other materials. The variations in plant material has been described as being due to differences in the bacteria residing in the plant. The question to investigate is whether or not these variations in the concentration can be used to determine the provenance of the sample.



Krouse Fig 1.png

Below is a table listing the natural abundances of Selenium

Natural abundance of selenium

Isotope Abundance
Se-74 0.86%
Se-76 9.23%
Se-77 7.60%
Se-78 23.69%
Se-80 49.80%
Se-82 8.82%

Below are possible PAA reactions that may be used to observe specific Se isotopes

Reaction Half-life Relative activity Gamma-rays, keV (BR)
Se-74(gamma,n)Se-73 7.1 h 1.5E-1 361 (100)
Se-74(gamma,n)Se-73m 39 m 3.2 402 (4)
Se-74(gamma,np)As-72 26 h 1.0E-3 834 (100)
Se-76(gamma,n)Se-75 120 d 1.3E-2 265(29)
Se-77(gamma,p)As-76 26.4 h 4.4E-2 559(44)
Se-78(gamma,p)As-77 38.8 h 8.6E-2 239(2)
Se-80(gamma,n)Se-79m 3.9 m 5.9 96(10)
Se-80(gamma,np)As-78 1.5 h 2.2E-2 614(54)
Se-80(gamma,p)As-79 8.2 m 1.3 96(9)
Se-80(gamma,[math]a[/math]p)Ge-75 83 m 2.8E-1 265(11)

Can one perform PAA measurements of Se-82 and Se-76?

Se_PAA_Reactions

Experiments

PAA_Selenium_ActivityCalc

PAA Selenium/Soil Experiments

LB Se PAA Horse Feed Experiment

Background Signals

PAA_BackGrd_Det_A

Nickel Normalization

LB PAA Nickel Investigation

First Observation of Se lines

Using the 44 Machine at 7 kW power and 44 meV incident electron energy to produce a bremsstrahlung spectrum with a mean energy of 15 meV.


All runs lasting less than 214 seconds have time stamp that gives real time if you divide by clock frequency of 20 MHz.  The first 32 bits are used for a real time measurement.


MDA and Se mass Calculations

LB MDA/Se Mass Calculations

IAC Detector Efficiencies

LB PAA IAC Detector Efficiencies

IAC Detector Calibrations

LB April DetB DetA Calibration

Runlists

LB PAA Runlist 4/01/16 - 06/02/16

LB March 2017 Runlist

LB_May_2017_Irradiation_Day

Data Analysis

LB_Feb2017_Se_Investigations

References

User_talk:Brenleyt


<references/>

File:Krouse CanJournChem 40 1962 p367.pdf

Goryachev, A. M., & Zalesnyy, G. N. (n.d.). The studying of the photoneutron reactions cross sections in the region of the giant dipole resonance in zinc, germanium, selenium, and strontium isotopes. Retrieved September 16, 2016, from http://www-nds.indcentre.org.in/exfor/servlet/X4sSearch5?EntryID=220070

Goryachev, B. I., Ishkhanov, B. S., Kapitonov, I. M., Piskarev, I. M., Piskarev, V. G., & Piskarev, O. P. (n.d.). Giant Dipole Resonance on Ni Isotopes. Retrieved October 26, 2016, from http://www-nds.indcentre.org.in/exfor/servlet/X4sGetSubent?reqx=119235&subID=220597006&plus=1


Handbook on Photonuclear data for applications, cross sections, and spectra. (2000, October). Retrieved November 4, 2016, from http://www-pub.iaea.org/MTCD/Publications/PDF/te_1178_prn.pdf

MSDS

Selenium shot, amorphous, 2-6 mm, Puratronic, 99.999% Alfa Aesar product # 10603 File:AlphaAesarSelenium MDSD.pdf

Informative links

http://www.deq.idaho.gov/regional-offices-issues/pocatello/southeast-idaho-phosphate-mining/southeast-idaho-selenium-investigations/

https://inldigitallibrary.inl.gov/sti/3169894.pdf

http://giscenter.isu.edu/research/Techpg/sisp/index.htm


PAA_Research