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.
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[[File:Krouse_Fig_1.png | 200 px]]
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== Below is a table listing the natural abundances of Selenium==
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Natural abundance of selenium
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{| border="3"  cellpadding="5" cellspacing="0"
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|  Isotope|| Abundance
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|-
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| Se-74  || 0.86%
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|-
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| Se-76 || 9.23%
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|-
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| Se-77 || 7.60%
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|-
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| Se-78 || 23.69%
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|-
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| Se-80 || 49.80%
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|-
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| Se-82 || 8.82%
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|}
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== Below are possible PAA reactions that may be used to observe specific Se isotopes==
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 +
{| border="3"  cellpadding="5" cellspacing="0"
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|  Reaction|| Half-life ||Relative activity ||Gamma-rays, keV (BR)
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|-
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| Se-74(gamma,n)Se-73  || 7.1 h || 1.5E-1 || 361 (100)
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|-
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| Se-74(gamma,n)Se-73m  || 39 m || 3.2 || 402 (4)
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|-
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| Se-74(gamma,np)As-72  || 26 h || 1.0E-3 || 834 (100)
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|-
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| Se-76(gamma,n)Se-75  || 120 d || 1.3E-2 || 265(29)
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|-
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| Se-77(gamma,p)As-76  || 26.4 h || 4.4E-2 || 559(44)
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|-
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| Se-78(gamma,p)As-77  || 38.8 h || 8.6E-2 || 239(2)
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|-
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| Se-80(gamma,n)Se-79m  || 3.9 m || 5.9 || 96(10)
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|-
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| Se-80(gamma,np)As-78 || 1.5 h || 2.2E-2 || 614(54)
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|-
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| Se-80(gamma,p)As-79  || 8.2 m || 1.3 || 96(9)
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|-
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| Se-80(gamma,<math>a</math>p)Ge-75  || 83 m || 2.8E-1 || 265(11)
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|-
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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?=
  
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[[Se_PAA_Reactions]]
  
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==Neutron knockout of Se-82==
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=Experiments=
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If you knock a neutron out of Se-82 you produce the unstable isotope Se-81 which has a half life of 18 min and a meta-state with a 57 minute half life.
 
  
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<math>{82 \atop\; }Se (\gamma,n){81 \atop \; }Se</math>
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==[[PAA_Selenium_ActivityCalc]]==
  
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The prominent photons emitted have the following energies
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[[PAA Selenium/Soil Experiments]]
  
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262,276 keV for the 18 minute half life
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[[LB Se PAA Horse Feed Experiment]]
  
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and
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==Background Signals==
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[[PAA_BackGrd_Det_A]]
  
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260 & 276 keV for the 57 minute half life isotope
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==Nickel Normalization==
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[[LB PAA Nickel Investigation]]
  
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==Neutron knockout of Se-76==
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== First Observation of Se lines==
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If you knock a neutron out of Se-76 you produce the unstable isotope Se-75 which has a half life of 119 days.
 
  
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<math>{76 \atop\; }Se (\gamma,n){75 \atop \; }Se</math>
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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.
  
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The prominent photons emitted have the following energies
 
  
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136, 264, and 279 keV
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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.
  
  
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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. 
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== MDA and Se mass Calculations ==
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[[LB MDA/Se Mass Calculations]]
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==IAC Detector Efficiencies ==
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[[LB PAA IAC Detector Efficiencies]]
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==IAC Detector Calibrations==
 +
 
 +
[[LB April DetB DetA Calibration]]
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 +
==Runlists==
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[[LB PAA Runlist 4/01/16 - 06/02/16]]
 +
 
 +
[[LB March 2017 Runlist]]
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[[LB_May_2017_Irradiation_Day]]
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=Data Analysis=
 +
 
 +
 
 +
[[LB_Feb2017_Se_Investigations]]
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=References=
 +
 
 +
 
 +
[[User_talk:Brenleyt]]
 +
 
 +
 
 +
<references/>
  
 
[[File:Krouse_CanJournChem_40_1962_p367.pdf]]
 
[[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.
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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
 +
 
 +
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
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 +
 
 +
 
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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
 +
 
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=MSDS=
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[https://www.alfa.com/en/catalog/010603/ Selenium shot, amorphous, 2-6 mm, Puratronic, 99.999% Alfa Aesar product # 10603] [[File:AlphaAesarSelenium_MDSD.pdf]]
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=Informative links=
 +
 
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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]]
 
[[PAA_Research]]

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

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