Anastasios Lagoyannis Tandem Accelerator Laboratory Institute of Nuclear Physics

1. Recent Developments of the PIGE setup at the Tandem Accelerator Facility of N.C.S.R. “Demokritos” AnastasiosLagoyannis Tandem Accelerator Laboratory Institute of Nuclear Physics N.C.S.R. “Demokritos”

2. Outline • The Tandem @ I.N.P. • General Considerations for PIGE • Target preparation and characterization • Charge measurement • Experimental Apparatus • Proposed measurements • Conclusions A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

3. The 5.5 MV VdG Tandem accelerator @ I.N.P. A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

4. Basic Experimental Tools A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

5. General Considerations for PIGE • Suitable Targets thin for resonances • thick for yield and validation • well characterized • Charge measurement Effective way of measuring the current (cross checked if possible) • Experimental Apparatus High efficiency • Good resolution • Placed to appropriate angles • Analyzing Software A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

6. Target Preparation Requirements Means of acquisition: • Thin target i.e. Self – supported / Thin substrate • Chemical and Thermal stability • Electrical conductivity • Act as charge reference Tgt Gold Carbon Possible Solution • Purchase • Evaporation BUT : Resistive Stoichiometry ??? Electron gun Thickness ??? Evaporator @ I.N.P. Demokritos A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

7. Target Characterization X – Ray Fluorescence • Beam - less • Using standards • Unsuitable for Z < Al Rutherford Back Scattering • Depth profiling • Suitable for sandwich like targets • Problematic for low Z EBS and NRA • Depth profiling • Depends on previous measurements • Good for low Z A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

8. Charge measurement I Traditional way(s) Downsides • Sophisticated Faraday cups • Suppression voltages (collimator and target) • Bending magnets • Insulating targets • Change of beams’ charge Alternatives Surface barrier detector at backward angles Beam Chopper Use of the RBS technique with a heavy element on target Independent of the target A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

9. Charge measurement II • Periodic movement In/Out (programmable) • Wing: Thin Au layer on Al • A SSB detects the backscattered from Au • Coincidence signals for In/Out • No additional NIM modules • Needs calibration at the beginning Beam Chopper A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

10. Experimental apparatus • Electronically controlled turntable • Initial angles: 0o – 55o – 90o - 165o • 4 HPGe detectors (1 – 80%, 3 – 100%) • 2 Compton suppression BGO’s • Possibility of mounting backward Si detector • Possibility of mounting Si annular detector • Air / Water cooled target • NIM electronics • Singles Fast ADC DAQ • CAMAC event by event DAQ A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

11. Experimental Procedure • Preparation/characterization of the targets • Energy and Efficiency calibration of Ge detectors using point sources • Q x Ωcalculation for the Si detector using RBS spectra from gold • Determination of Q using chopper and RBS technique • Machine calibration using either 27Al(p,γ) or threshold reactions • Peak analysis using two different algorithms to account for the bias error • Data validation using thick targets and appropriate software A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

12. Proposed Measurement for 32S Candidates: 32S(d,pγ) 33S Εγ = 841keV Z. Elekes et al. NIM B168 (2000), 305 32S(p, γ) 33S No PIGE related publications 32S(p,p’γ) 32S Εγ = 2230 keV C. Tsartsarakos et al. NIM B45 (1990), 33 Experiment Angle: 55o Energy range : 3000 – 7000 keV Steps: Varying (excitation function depending) Target: sandwich like Ta – TiS - Carbon C. Tsartsarakos et al. NIM B45 (1990), 33 A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

13. Proposed Measurement for 10B - 11B Candidates: R. Mateus et al. NIM B219 (2004), 519 10B(p,αγ) 7Be Εγ = 429keV C. Boni et al. NIM B35 (1988), 80 T. R. Ophel et al. Nucl. Phys. 33 (1962), 198 T. R. Ophel et al. Nucl. Phys. 33 (1962), 198 10B(p,p’γ) 10B Εγ = 718keV V. Michaud et al. NIM B85 (1994), 881 11B(p,p’γ) 11B Εγ = 2125 MeV C. Boni et al. NIM B35 (1988), 80 M. Koerdel et al. NIM B261 (2007), 520 11B(p,γ) 12C Εγ = 11.68MeV A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

14. Proposed Measurement for 10B - 11B 10B(p,αγ)7Be 11B(p,p’γ) 11B 10B(p,p’γ) 10B 11B(p,p’γ) 11B V. Michaud et al. NIM B85 (1994), 881 C. Boni et al. NIM B35 (1988), 80 10B(p,αγ)7Be Experiment Angle: 55o Energy range : 1000 – 5000 keV 10B(p,αγ)7Be Steps: Varying (excitation function depending) Target: 11B, 10B on thick Ta R. Mateus et al. NIM B219 (2004), 519 A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

15. Proposed Measurement for 13C Candidates: 13C(p, γ) 14Non 1.75 MeV resonance 90% Εγ = 9.16MeV H. H. Woodbury et al. Phys. Rev. 92 (1953), 1199 J. B. Marion et al. Phys. Rev. 104 (1956), 1028 Experiment Angle: 55o - 90o - 125o Energy range : 1000 – 5000 keV Steps: Varying depending on the excitation function Target: Gold on 13C foil A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

16. Conclusions Summary • Means for target characterization • Effective charge measurement • Efficient HPGe experimental setup • A set of case studies • Appropriate software for validation • PIGE cross sections A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”

17. Collaborators A. Axiotis, V. Paneta and S. Harissopulos M. Kokkoris P. Misaelides A. Lagoyannis Institute of Nuclear Physics NCSR “Demokritos”