PHY-1263281 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, 88003 2Cyclotron Institute, Texas A&M University, College Station, TX, 78843

Outline What Internal Conversion is Motivation Theory PHY-1263281 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.

Internal Conversion Process PHY-1263281 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

PHY-1263281 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 1.425. Previous experiment determined the αK to be 1.29 ± 0.11

PHY-1263281 Theory

PHY-1263281 Source Preparation 111mCd was created by activating a 95% enriched 110Cd with thermal neutrons in the TRIGA reactor

HPGe Detector Pre-Amp Sample Ge Crystal Liquid N2 PHY-1263281 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.

Impurity Analysis An Impurity Analysis tells us: PHY-1263281 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)

PHY-1263281 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

Area Analysis X-Ray Area 111mCd 150keV 202,652(499) Impurity PHY-1263281 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.

Results Theory (With Vacancy) (No Vacancy) Previous Experiment* PHY-1263281 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, 150.8 keV, E3 Transition in 111Cdm and comparison of experimental and theoretical high multipole order internal conversion coefficients, Phys. Rev. C 35, 2294 (1987)

PHY-1263281 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 10-15 to 10-17s, which is much longer than the 10-18 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

Acknowledgements Dr. Hardy’s Group Cyclotron Institute Dr. Yennello PHY-1263281 Acknowledgements Dr. Hardy’s Group Cyclotron Institute Dr. Yennello REU group

PHY-1263281 Questions?