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Radiation Sources

Radiation Sources. Heavy nuclei are unstable against spontaneous emission of  particles. Barrier penetration. Higher energy ► easier penetration ► short half-life ► less practical. Lower energy ► less penetrability ► long half-life ► less activity. Most sources ► 4-6 MeV.

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Radiation Sources

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  1. Radiation Sources • Heavy nuclei are unstable against spontaneous emission of  particles. • Barrier penetration. • Higher energy ► easier penetration ► short half-life ► less practical. • Lower energy ► less penetrability ► long half-life ► less activity. • Most sources ► 4-6 MeV. • Investigate the famous alpha sources and the corresponding energies and branching ratios. • Most famous is 241Am. Smoke detectors. • Short range ►thin sources. • Q-value. • Recoil. • Kinetic energy of  as a function of Q. • Nuclear reactions as sources of ’s. Modes of decay. Energy Resolution Neutron source? Energy loss. Density effect & units of thickness. HW 2 Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  2. Radiation Sources Charged particles. Continuous energy loss. Gamma. Catastrophic. HW 3 Different units used for sample (or target) thickness Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  3. Radiation Sources Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  4. Radiation Sources • Spontaneous fission. • Transuranic isotopes (example 252Cf). • Also alpha emitters. • Two fragments (and few neutrons) per fission. • Fragments are positive ions (highly charged ~ Z). • Strong energy loss. • Usually thin coating on a flat backing. • Only one fragment per fission escapes the sample. HW 4 ? Induced Light Heavy Source of fragments and neutrons. Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  5. Radiation Sources • Many laboratory  sources are  sources. • Needs to be relatively thick source. • Parent half-life and daughter energy! • Catastrophic interaction. • Energy and efficiency calibration. • If for efficiency calibration, source needs to be thin, or correction factors. • Small “width” compared to best detector resolution. • Activity and effect on calibration. Annihilation TOI is better! Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  6. Radiation Sources HW 5 Relative intensity I Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  7. Signal Processing - Introduction PHA Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  8. Radiation Sources Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  9. Radiation Sources • Laboratory  sources limited to < 3 MeV. • How can we get the 6.13 MeV transition in 16O? • 27Al(p,) and other charged particle induced reactions (could suffer Doppler effect). • Also neutron induced reactions. HW 6 Energy loss. Stopping power. Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  10. Radiation Sources • Bremsstrahlung from fast electrons. • Continuum. • High energy electrons and high Z material. • Filters. Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  11. Radiation Sources http://www.kayelaby.npl.co.uk/atomic_and_nuclear_physics/4_2/4_2_1.html • Characteristic X-rays. Elemental analysis. • Energy increases with Z. • Fluorescent yield (competing Auger). • Self absorption; source thickness. • Different excitation mechanisms: • EC (accompanied by  and/or inner bremsstrahlung IB. (511?). • IC (accompanied by bremsstrahlung). • Incident “beam” on a target, low Z ► soft X-rays; high Z ► hard X-rays. K K X-ray “XRF” Project 2 Electrons: X-ray exit window at large angles.  Clean  PIXE Lining shield. Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  12. Radiation Sources PIXE Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  13. Radiation Sources Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  14. Radiation Sources Synchrotron radiation. Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

  15. Radiation Sources Neutron sources • We will discuss neutron sources later. • You are asked to prepare your own presentation on this subject. • Don’t limit yourself to Knoll. Radiation Detection and Measurement, JU, First Semester, 2010-2011 (Saed Dababneh).

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