1. PHY
Precise Measurement of the Internal Conversion Coefficient for the E3 decay from the 111mCd Isomer
Laura G. Pineda1,2, N. Nica2, J.C. Hardy2 1Reu Student from Department of Chemical Engineering, New Mexico State University, Las Cruces, NM, Cyclotron Institute, Texas A&M University, College Station, TX, 78843

2. Outline What Internal Conversion is Motivation Theory
PHY
Outline
What Internal Conversion is
Motivation
Theory
Preparation of the sample
Apparatus
Analyses
Impurity
Peak
Area
Results
Conclusion
Source preparation slide needs to be added, references page. Motivation page. All decay schemes are built using internal conversion coefficient values.

3. Internal Conversion Process
PHY
Internal Conversion Process
A nuclear γ de-excitation process where:
Either a γ ray is emitted
Or an electron, in any shell, gets energy and is ejected from the atom
Ejected electron leaves behind a hole
An electron from a higher energy level then occupied it
An x-ray may be emitted
X ray emits when the vacancy is occupied.. Penetrates the nucleus.. Process, not reaction. Nucleus prefers the ground state, not the atom.
Gamma ray
Internal Conversion

4. PHY
Motivation
Depending on the treatment of the atomic vacancy, the αK value is calculated differently
Including the atomic vacancy, αK equals to 1.450
Neglecting the atomic vacancy, αK equals to
Previous experiment determined the αK to be 1.29 ± 0.11

5. PHY
Theory

6. PHY
Source Preparation
111mCd was created by activating a 95% enriched 110Cd with thermal neutrons in the TRIGA reactor

7. HPGe Detector Pre-Amp Sample Ge Crystal Liquid N2
PHY
HPGe Detector
Pre-Amp
Sample
Ge Crystal
Liquid N2
High Purity Germanium detectors use semiconductor properties in order to detect when an electron from the germanium crystal has gained enough energy to leap from the valence band into the conduction band.

8. Impurity Analysis An Impurity Analysis tells us:
PHY
Impurity Analysis
An Impurity Analysis tells us:
What impurity isotopes were present in the sample
Which atoms to take into consideration when calculating the intensity of the 111mCd X-ray
The atoms that interfere with our X-ray region are:
117Cd (2.49h)
116mIn (54.2m)
117In (43.3m)
117mIn (116.2m)
115Cd (53.5h)

9. PHY
Peak Fitting Analysis
Because X-rays tend to overlap each other, the X-ray region was fitted as a whole, and later corrected in the Area Correction Analysis step.
Figure 1: 111mCd 150keV peak
Figure 2: X-Ray region

10. Area Analysis X-Ray Area 111mCd 150keV 202,652(499) Impurity
PHY
Area Analysis
X-Ray
Area
111mCd 150keV
202,652(499)
Impurity
Gamma Area
X-ray Corr
111mCd 245keV
310579(565)
20,048(377)
117Cd 274keV
855(20)
269(12)
117Cd 344keV
518(22)
302(19)
116mIn 1097keV
172(31)
13(2)
116mIn 417keV
173(2)
14(2)
117In 553keV
1399(45)
402(29)
117mIn 315keV
433(33)
746(59)
75(6)
Recommended values for intensity.. Add the x ray value.

11. Results Theory (With Vacancy) (No Vacancy) Previous Experiment*
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Results
Theory
(With Vacancy)
(No Vacancy)
Previous Experiment*
Our Result
1.450
1.425
1.29(11)
1.458(18)
Zs. Németh, and Á. Veres, keV, E3 Transition in 111Cdm and comparison of experimental and theoretical high multipole order internal conversion coefficients, Phys. Rev. C 35, 2294 (1987)

12. PHY
Conclusion
When an electron is ejected, the average time it takes for a higher electron to occupy the K atomic vacancy is in the order of to 10-17s, which is much longer than the s it takes for an electron to leave the atom.
Thus the vacancy must be considered in the calculation of the αK value.
Split into two

13. Acknowledgements Dr. Hardy’s Group Cyclotron Institute Dr. Yennello
PHY
Acknowledgements
Dr. Hardy’s Group
Cyclotron Institute
Dr. Yennello
REU group

14. PHY
Questions?