Measurements of Neutron Activation of 76 Ge and 136 Xe

1. Measurements of Neutron Activation of 76Ge and 136Xe James Esterline MeghaBhike, Josh Bradt, Brent Fallin, Sean Finch, Matt Gooden, Calvin Howell, John Kelley, Werner Tornow

2. Measurements of Neutron Activation of 76Ge and 136Xe James Esterline MeghaBhike, Josh Bradt, Brent Fallin, Sean Finch, Matt Gooden, Calvin Howell, John Kelley, Werner Tornow

3. Neutron Activation • Spallation from cosmic m • Interest in contributions to background in ROI for 0n2b decay • Secondary interest as nuclear structure study • Analysis ongoing: progress and partial results here presented

4. Experimental Setup • Neutrons generated by 2H(d,n)3He • Utilized deuteron beam from TUNL’s DENIS • Pulsed at 2.5 MHz to enable time correlations • Produced neutron at energies En = 8.0, 12.0 MeV • Only presenting at 8 MeV • Ran in (presently disassembled) Shielded Source Area • Maximum suppression of background neutrons, photons

5. DENIS Beam pickoff

6. DENIS NTOF

7. Experimental Setup • Illuminate samples with collimated neutron beam • Germanium as thick foil (irregular shape for enriched) • Xenon in metal spheres • Use Fe foils instead of direct neutron flux measurement for normalization

8. Experimental Setup • Illuminate samples with collimated neutron beam • Germanium as thick foil (irregular shape for enriched) • Xenon in metal spheres • Use Fe foils – unfortunately, shares prominent transition energy (847 keV) with germanium • Uncertainty of metal composition for Xe • Added Ni foils

9. Experimental Setup • Initially used clover detectors • One detector with only two of four segments operational; other with all four • Switched to 60% HPGe detectors • Have small contributions from scattered neutrons activating detectors

10. Data Acquisition and Analysis • Time of flight between pickoff and detection

11. Data Acquisition and Analysis • Time of flight between pickoff and detection Desired neutron activation [Walk] [Source g] Rescattered, breakup neutrons

12. Data Acquisition and Analysis • Energy deposited in germanium detectors

13. Data Acquisition and Analysis • Data processed in one- or two-hour runs • Flight time gates determined in aggregate • 5% of peak height on signal peak • Focus on maximizing accidental gate width

14. Data Analysis

15. Data Analysis

16. Data Acquisition and Analysis • Data processed in one- or two-hour runs • Flight time gates determined in aggregate • 5% of peak height on signal peak • Focus on maximizing accidental gate width • Energy calibrations determined individually for each run using prominent peaks (both signal and background)

17. Data Acquisition and Analysis • Data processed in one- or two-hour runs • Flight time gates determined in aggregate • 5% of peak height on signal peak • Focus on maximizing accidental gate width • Energy calibrations determined individually for each run using prominent peaks (562 keV (Ge)/847 keV (Fe), 40K, n-p capture, 214Bi)

18. Data Acquisition and Analysis

19. Data Acquisition and Analysis

20. Data Acquisition and Analysis

21. Data Acquisition and Analysis • Apply calibrations and time of flight cuts

22. Data Acquisition and Analysis

23. Data Acquisition and Analysis • Shared energy between detectors

24. Data Acquisition and Analysis • Shared energy between detectors • Also look at coincidence spectra

25. Data Acquisition and Analysis • Obtain (~ d.c.s.) values for various transitions

27. Results • Transitions in the ROI for Ge, Xe

28. Ge Spectra 2040.7 keV(from E*(1+,2+) = 3951 keV) 2035 keV(74Ge)

29. Ge Spectra 2040.7 keV(from E*(1+,2+) = 3951 keV) 2035 keV(74Ge)

30. Ge Spectra 2040.7 keV(from E*(1+,2+) = 3951 keV) 2035 keV(74Ge)

31. Xe Spectra J. Bradtet al., 2012

32. Future Work • Obtain estimates of total cross sections • Apply scheme in full to natGe and 136Xe