Accelerator Physics, JU, First Semester, (Saed Dababneh). 1 Electron pick-up. ~1/E What about fission fragments????? Bragg curve stochastic energy straggling. Energy loss is a stochastic process, thus energy straggling. Principles of Spectrometry Target Accelerated beam

Accelerator Physics, JU, First Semester, (Saed Dababneh). 2 Hadrontherapy

Accelerator Physics, JU, First Semester, (Saed Dababneh). 3 Principles of Spectrometry Accelerated beam

Accelerator Physics, JU, First Semester, (Saed Dababneh). 4 Range of charged particles Compare to gamma … !!! Range straggling? Mean and extrapolated range. An “old” idea to measure energy..! Surface barrier, PIPS. For a detector to register the full energy of charged particles, its thickness should be more than the range at that energy. Sometimes we look for partial energy. E-  E detection. position sensitive detectors. Energy and position sensitive detectors. Radioactive ion beams. Radioactive ion beams. Counts number Principles of Spectrometry

Accelerator Physics, JU, First Semester, (Saed Dababneh). 5 E-  E detection. Principles of Spectrometry

Accelerator Physics, JU, First Semester, (Saed Dababneh). 6 Use SRIM Data to reproduce the graphs. Energy deposited in an absorber (or detector). Or, if “thin” absorber: Both are not accurate. Why? You can do it better with SRIM. Principles of Spectrometry

Accelerator Physics, JU, First Semester, (Saed Dababneh). 7 Principles of Spectrometry

Accelerator Physics, JU, First Semester, (Saed Dababneh). 8

9 Stopping time Problem…!! Detector response time. Effect on Doppler shift and broadening in nuclear reactions. Compare the application of scaling laws and Bragg-Kleeman rule with SRIM. Work out many examples. Ranges? Principles of Spectrometry Units? Applicability? HW 12 HW 13

Accelerator Physics, JU, First Semester, (Saed Dababneh). 10 Fast Electron Interactions. Collisional Collisional Radiative (Bremsstrahlung) Radiative (Bremsstrahlung) What is the main difference for positrons? Principles of Spectrometry

Accelerator Physics, JU, First Semester, (Saed Dababneh). 11 Range.. ! Range x density Monoenergetic Electron Beam What about  electrons? Principles of Spectrometry

12 nearly monoenergetic. IC Auger High keV to MeV range. Few keV. Energy Resolution Easily self absorbed. Principles of Spectrometry Accelerator Physics, JU, First Semester, (Saed Dababneh).

13 Backscattering Fraction backscattered Detector entrance window or dead layer. Source backing. Principles of Spectrometry

Accelerator Physics, JU, First Semester, (Saed Dababneh). 14 Principles of Spectrometry

Accelerator Physics, JU, First Semester, (Saed Dababneh). 15 Principles of Spectrometry  From 185 W. Endpoint = 0.43 MeV. In Al

Accelerator Physics, JU, First Semester, (Saed Dababneh). 16 Nuclear Reactions X(a,b)Y First in 1919 by Rutherford: 4 He + 14 N  17 O + 1 H 14 N( ,p) 17 O Incident particle may: change direction, lose energy, completely be absorbed by the target…… Target may: transmute, recoil…… b =   Radiative Capture. If B.E. permits  fission (comparable masses). Different exit channels a + X  Y 1 + b 1  Y 2 + b 2  Y 3 + b 3 …….

Accelerator Physics, JU, First Semester, (Saed Dababneh). 17 Nuclear Reactions Recoil nucleus Y could be unstable   or  emission. One should think about:  Reaction dynamics and conservation laws i.e. conditions necessary for the reaction to be energetically possible.  Reaction mechanism and theories which explain the reaction.  Reaction cross section i.e. rate or probability.

Accelerator Physics, JU, First Semester, (Saed Dababneh). 18 Nuclear Reaction Energetics (revisited) If the reaction reaches excited states of Y 58 Ni( ,p) 61 Cu Highest proton energy less proton energy even less ….

Accelerator Physics, JU, First Semester, (Saed Dababneh). 19 Nuclear Reaction Energetics (revisited)

20 Nuclear Reactions Categorization of Nuclear Reactions According to: bombarding particle, bombarding energy, target, reaction product, reaction mechanism. Bombarding particle:  Charged particle reactions. [ (p,n) (p,  ) ( ,  ) heavy ion reactions ].  Neutron reactions. [ (n,  ) (n,p) ….. ].  Photonuclear reactions. [ ( ,n) ( ,p) … ].  Electron induced reactions…………. Bombarding energy:  Thermal.  Epithermal.  Slow.  Fast.  Low energy charged particles.  High energy charged particles. Neutrons. ? Accelerator Physics, JU, First Semester, (Saed Dababneh).

21 Nuclear Reactions Targets:  Light nuclei (A < 40).  Medium weight nuclei (40 < A < 150).  Heavy nuclei (A > 150). Reaction products:  Scattering. Elastic 14 N(p,p) 14 N Inelastic 14 N(p,p / ) 14 N*  Radiative capture.  Fission and fusion.  Spallation.  ….. Reaction mechanism:  Direct reactions.  Compound nucleus reactions. More …. What is a transfer reaction….????? Stripping Pickup Resonant Non-resonant Accelerator Physics, JU, First Semester, (Saed Dababneh).