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H.-W. Becker, LIBRA-meeting, March 2009, Athen

Activities and Opportunities at the accelerator lab in Bochum. H.-W. Becker, LIBRA-meeting, March 2009, Athen. High Resolution Depth Profiling with Low Energy Nuclear Resonances:. 500 kV machine. beam resolution: 30-40 eV total resolution ~ 70 eV (mainly doppler broadening).

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H.-W. Becker, LIBRA-meeting, March 2009, Athen

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  1. Activities and Opportunities at the accelerator lab in Bochum H.-W. Becker, LIBRA-meeting, March 2009, Athen

  2. High Resolution Depth Profiling withLow Energy Nuclear Resonances: 500 kV machine beam resolution: 30-40 eV total resolution ~ 70 eV (mainly doppler broadening) isolated, narrow resonances high stopping power low background 20 eV stability:

  3. Resonances below 500 keV:

  4. Investigation of Diffusion Processes in Minerals to determine scales in time, temperature and pressure for samples from the field to understand plastic flow in the earths crust Olivin (Fe,Mg)2SiO4 10 nm native sample artificial layer enriched in 29Si (PLD)

  5. Hydrogen depth profiling with the 4p-detector

  6. Hydrogen storage systems for future automotive applications Hydrogen loaded Pt-Ti-Cr-layer RBS NRA 1H(15N,ag)12C

  7. Going to low Hydrogen concentrations …. figure of merit (set by Rauch et al.): sensitivity of 10 ppm requirements: vacuum better than 10-9 mbar capability for in situ surface cleaning (sputter gun, heating) low background in the detector

  8. Astrophysics with the Summing Crystal  4p-Geometry – summing over angular distribution  summing over cascades: Simpson, Dixon and Storey (1971) target enriched in 40Ca Bochum 4p-detector target natural Ca 40Ca(a,g)44Ti E = 4.53 MeV

  9. “seed “ abundances s process reaction network p-nuclei abundances p process The game of understanding p-process abundances Results: A. Spyrou, H.-W. Becker, A. Lagoyannis, S. Harissopulos and C. Rolfs, Phys. Rev. C 76, 015802 (2007)

  10. Target Beam BGD 92Mo(α,γ)96Ru @Eα= 10 MeV 12C(α,α) NaI + n 27Αl(n,γ)28Al Summing peak 11400 keV

  11. HPGe detector @ 90 deg. 4π ΝαΙ(Tl) summing detectors

  12. Efficiency calibration NaI Beam 12 inch x 12 inch 1g1/2 2g ½ . ½ = 1/4 3g ½ . ½ . ½ = 1/8 4g½ . ½ . ½ . ½ = 1/16 5g½ . ½ . ½ . ½ / ½ = 1/32 A. Spyrou, H.-W. Becker, A. Lagoyannis, S. Harissopulos and C. Rolfs, Phys. Rev. C 76, 015802 (2007)

  13. 27Al(p,γ)28Si in/out @ 992 keV

  14. Conclusion: …a lot of interesting things can be done within LIBRA

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