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Nuclear Spectroscopy & Imaging Stephen Cramer UC Davis / LBNL.

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Presentation on theme: "Nuclear Spectroscopy & Imaging Stephen Cramer UC Davis / LBNL."— Presentation transcript:

1 Nuclear Spectroscopy & Imaging Stephen Cramer UC Davis / LBNL

2 Nuclear Experiments Nuclear Forward Scattering – NFS SR Perturbed Angular Correlation Nuclear Resonance Vibrational Spectroscopy

3 Nuclear Experiments The trick 70 psec 3680 nsec 153 nsec off ~20 ns~133 ns on h Source Signal

4 Nuclear Lifetimes & Energies What works

5 Nuclear Forward Scattering ferrocene

6 Synchrotron Radiation Perturbed Angular Correlation (SRPAC)

7

8 The NRVS Experiment 100 eV … Detector: 1 eV1 meV    70 psec 3680 nsec 153 nsec off ~20 ns~133 ns on h Source Signal

9 FeN x H y Models HFe-N 2 DFe-N 2 Fe- 14 N 2 H 2 Fe- 15 N 2 H 2 Fe- 14 N 2 H 4 Fe- 15 N 2 H 4 N2N2 N2H2N2H2 N2H4N2H4

10 Fe Protein NRVS [Fe 4 S 4 ] 2+  Any redox level  Low frequency modes  Quantitative simulation [Fe 4 S 4 ] 1+ [Fe 4 S 4 ] 0

11 Nuclear Needs Nuclear Forward Scattering – NFS SR Perturbed Angular Correlation Nuclear Resonance Vibrational Spectroscopy

12 X-Ray Microtomography Carolyn Larabell - NIH funded facility at ALS Image of yeast cell

13 Diffraction-Enhanced Imaging x http://www.iit.edu/~chapman/AAPM/sld027.htm

14 Mössbauer cross sections are 500 x photoelectric c. s.  but linewidths are 10 8 smaller ‘Nuclear contrast’   Why do it? less radiation damage zero background

15 Nuclear Imaging Fe Kr / Xe Lanthanide nanoparticle tags

16 Nuclear Imaging Needs Orders of magnitude more flux Higher energies (30-70 keV) Nano eV (nuclear) monochromators Suitable bunch schemes Better (picosecond) detectors

17 Nuclear Future? I dream of things that never were … and say why not ? (RFK) To accomplish great things, we must not only act, but also dream; not only plan, but also believe. (Anatole France)


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