1. Accelerator technique FYSN 430 Fall 2008

2. Syllabus Task: determine all possible parameters for a new accelerator project Known: Scope of physics done with an accelerator Needed –Accelerator type –Building –Devices…

3. Physics case Nuclear physics Study of neutron rich isotopes Study of heavy isotopes Nuclear reactions Applications Isotope production with protons Radiation damage tests (SEE) Possible future plans ?

4. Relevant parameters Accelerated isotopes Beam energies (low and high) Beam intensities Other beam properties –Emittance –Time structure –…

5. Coulomb barrier for fusion reactions (production of heavy isotopes) For fusion reactions the repulsive Coulomb barrier has to be overcome Coulomb force Coulomb potential that q 1 feels

6. r1r1 r2r2 r C = r 1 + r 2 q 1, A 1 q 2, A 2

7. Distance at which nuclei touch each other Coulomb energy at r c

8. Examples Fe + Pb A 1 = 56, Q 1 = 27 A 2 = 208, Q 2 = 82 W C = 272.5 MeV or 4.9 MeV/u for Fe C + Sn A 1 = 12, Q 1 = 6 A 2 = 120, Q 2 = 50 W C = 49.8 MeV or 4.15 MeV/u for C

9. Note! Remember also recoil: The compound nucleus moves due to recoil Conservation of momentum: Kinetic energy of the recoil

10. Total kinetic energy (lab. Frame) needed for the projectile E proj =E coul +E recoil Usually a small correction Rule of thumb: E proj, lab /A proj = 5 MeV/u

11. Proton induced fission Reaction (e.g.) proton + U Coulomb wall approx. 15.4 MeV p- induced and n- induced

12. Mass distribution Higher proton energy

13. High LET beams

14. Low energy limit Are energies below 5 MeV/u interesting? No fusion Advantage: Coulomb excitation Ask the physicists for the lower limit E.g. 40 MeV 40 Ar: 1 MeV/u

15. Beam intensities Isotope production –High (100  A) Nuclear spectroscopy –A few pna – a few p  A SEE tests –100 particles/s (aA) and more

16. Some limits Energy –Protons: 1-100 MeV –Other ions: 1- nx10 MeV/u Intensity –aA – 100  A

17. Possible accelerators Linear accelerator –Wideröe –Alvarez –Electrostatic (Tandem) Cyclotron –Super conducting vs. conventional Synchrotron