1. (n,p) emission channeling measurements on ion-implanted beryllium INTC-P-233 J.P. Araujo, J.G. Correia, M. Dawson, M. Faist, H.O.U. Fynbo, C. Granja, J. Jakubek, M. Jentschel, U. Köster, V. Nesvizhevsky, S. Pospisil, T. Soldner, J. Uher, J. Vacik, A. Van Overberghe, U. Wahl

2. Characteristic EC patterns for silicon lattice

3. Emission channeling measurements: basic principles

4. Elements for which emission channeling experiments have been reported Mg IS453: EC with short-lived isotopes Co Ni EC with neutron-induced charged particle emission He LiBe B Na

5. Setup for neutron-induced charged particle EC J.P. Biersack et al., Nucl. Instr. Meth. 108 (1973) 397. J.P. Biersack et al., Nucl. Instr. Meth. 170 (1980) 151. J.P. Biersack et al., Nucl. Instr. Meth. 188 (1981) 411.

6. Triton EC pattern from 6 Li(n,  )t in LiF crystals

7. Alpha EC pattern from 10 B(n th,  ) in Si:B 10 16 B/cm 3 in Si J.P. Biersack et al., Nucl. Instr. Meth. 170 (1980) 151.

8. Thermal neutron-induced particle emission

9. New interest: heavily boron doped silicon Si:B with gas immersion laser doping (5  2)  10 21 B/cm 3 E. Bustarret et al., Nature 444 (2006) 465. substitutional fraction?

10. New interest: heavily boron doped diamond E. Bustarret et al., Phys. Rev. Lett. 93 (2004) 237005. T. Klein et al., Phys. Rev. B 75 (2007) 165313.

11. New technical possibility: intense 7 Be beam at ISOLDE PSI: 2 mA 590 MeV protons onto graphite target for pion production

12. Spallation products

13. Procedure 1.Break graphite into pieces 2.Put into Pb-shielded container 3.Transport to ISOLDE 4.Fill ISOLDE target container 5.Heat container to 1700 °C 6.Ionize Be with RILIS

14. Extraction of 7,10 Be + beams with 300 pnA (i.e. 2E12 ions per second or 1 GBq/hour) for many hours! U. Köster et al., Nucl. Instr. Meth. B204 (2003) 343.

15. 7 Be(n,p) spectrum measured with test sample

16. Be doping of GaN GaN is a wide band gap (3.39 eV) semiconductor with many applications: high-performance blue LEDs long-lifetime blue/violet laser diodes (Blu-ray Disc) UV detectors high-speed field effect transistors … present p-type doping with Mg (208 meV acceptor activation energy) might be replaced by Be (90-250 meV)

17. Be doping of GaN Calculated total energy surfaces for Be interstitials in GaN C.G. Van De Walle and J. Neugebauer, J. Appl. Phys. 95 (2004) 3851. and AlN

18. Ternary wide band gap alloy: Be x Zn 1-x O Y.R. Ryu et al., Appl. Phys. Lett. 88 (2006) 052103.

19. 7 Be half-life dependence on s-electron-density 2. Be 3. Au 4. Ta 5. Al 6. graphite 7. LiF 8. Al 2 O 3 1. BeO, BeF 2, Be(C 5 H 5 ) 2 P. Das and A. Ray, Phys. Rev. C 71 (2005) 025801.

20. ILL’s Neutrograph beam line Thermal neutron flux: 3E9 cm -2 s -1 Direct view to core: fast neutrons, high gamma background

21. ILL’s PF1B beam line Cold neutron flux: 2E10 cm -2 s -1 (capture equivalent) Ballistic supermirror neutron guide: excellent suppression of high energy neutrons H. Abele et al., Nucl. Instr. Meth. A562 (2006) 407.

22. Test setup

23. Medipix2 performance J. Jakubek et al., Nucl. Instr. Meth. A571 (2006) 69.

24. Cluster analysis for particle identification J. Jakubek et al., Nucl. Instr. Meth. A560 (2006) 143.

25. Charged particle identification in high background Cluster analysis gives peak/background ratio > 40

26. Sample positioning

27. Beam time estimations for Neutrograph beam line

28. Beam request Implantation of crystals of Al, Al 2 O 3, AlN, Be, C, ZnO, GaN with 7 Be and 9 Be at GLM About 1E14 atoms/sample (=15 MBq, =12 uSv/h at 10 cm, if swallowed cancer risk corresponds to 1.3 cigarette packs smoked) 6 shifts for implantation plus 2 shifts for beam tuning and optimization of 7 Be/ 7 Li ratio ISOLDE beam time needs to be synchronized with availability of activated PSI graphite and ILL reactor cycles!

29. Sample treatment thermal treatment to anneal crystal damage verify diffusion broadening of implantation peak by neutron depth profiling

30. MEDIPIX2 PARTNERS - U INFN Cagliari - CEA-LIST Saclay - CERN Genève - U d'Auvergne Clermont - U Erlangen - ESRF Grenoble - U Freiburg - U Glasgow - IFAE Barcelona - Mitthoegskolan - MRC-LMB Cambridge - U INFN Napoli - NIKHEF Amsterdam - U INFN Pisa - FZU CAS Prague - IEAP CTU in Prague - SSL Berkeley SPOKESMAN Michael CAMPBELL Deputy Jan VISSCHERS http://medipix.web.cern.ch/MEDIPIX/

31. Charged particle emission from beryllium isotopes 2.9(5)% 770 keV D.E. Alburger et al., Phys. Rev. C 23 (1981) 473.

32. GaN crystal principal axes [0001] [1102] [1101] [2113]

33. Why Be to alloy ZnO? Y.R. Ryu et al., Appl. Phys. Lett. 88 (2006) 052103.

34. Sample characterization by (RBS)  Zn RBS signal: minimum yield  min =3.6%  somewhat higher than the virgin sample (  min  1.8%)  remaining damage visible but low level; relatively good crystalline quality Random and [0001] aligned RBS (2 MeV 4 He) of high-dose 1.1  10 15 cm  2 implanted sample after T A =900°C