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Prospects to measure 8 B production

This article explores cross-section measurements and precision required for the 8B production project, as well as the angular distribution and theoretical calculations needed. It also discusses the choice between direct or reverse kinematics and different experimental set-ups available.

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Prospects to measure 8 B production

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  1. Prospects to measure 8B production VLADIMIR KRAVCHUK Laboratori Nazionali di Legnaro, Italy

  2. CONTENTS • INTRODUCTION • CROSS-SECTION MEASUREMENTS AND PRECISION • ANGULAR DISTRIBUTION • DIRECT OR REVERSE KINEMATICS? • EXPERIMENTAL SET-UPSa) Internal options: LNL-TANDEM/CN, Legnaro i) LNL - CN ii) LNL – TANDEM RIPEN+PHOSWICH SET-UP iii) LNL – TANDEM EXOTIC+RIPEN SET-UPb) External options i) LNS – TANDEM MAGNEX+EDEN SET-UP Catania, Italy ii) IUAC – 15 MV PELLETRON HYRA+NAND SET-UP, New Dehli, India iii) JINR – U400 CYCLOTRON AKULINA+DEMON SET-UP, Dubna, Russia iv) JYU – K130 CYCLOTRON SET-UP TO BE STUDIED, Jyvaskyla, Finland • TARGETS • CONCLUSION

  3. 1. INTRODUCTION In the article of Rubbia et al. the 8B nucleus is considered as a neutrino source producing relatively high-energy neutrinos: The reaction proposed for the 8B production is: with the decay time of 0.77 s. In the same article the plot of the total cross section of the indicated process is demonstrated as a function of 3He incoming energies together with the incoming energies for the reverse kinematics:The optimum energy for collisions suggested in the article of Rubbia et al. is ~20 MeV for Li ions on He target. C. Rubbia et al., Nucl. Instr. and Meth. A 568 (2006) 475-487

  4. 2. CROSS-SECTION MEASUREMENTS AND PRECISION and references therein 1. What precision in the cross-section measurements is required for the project?

  5. 3. ANGULAR DISTRIBUTION Angular distribution is measured only until E(3He)=5.7 MeV 2. Presumably there is a need to measure the angular distribution. What angular resolution is required? This information will help in the choice of the set-up and geometry. 3. Do wee need to perform theoretical calculations (using presumably DWBA code) for the possible comparison with the experimental results and for the extension in the whole energy range of interest?

  6. 4. DIRECT OR REVERSE KINEMATICS? D. Neuffer, Nucl. Instr. and Meth. A 585 (2008) 109-116 LISE++ Kinematics Calculations 1) 8 MeV 3He (16 MeV 6Li) – intermediate case; 2) 10 MeV 3He (20 MeV 6Li) – optimum energy according to the articles of Rubbia et al. and Neuffer; 3) 5.5 MeV 3He (11 MeV 6Li) – energy with the maximum reaction cross-section from the data in literature. For each of the energy cases described above 4 calculations were performed: two-body direct kinematics 3He + 6Li -> 8B + 1n; elastic scattering direct kinematics 3He + 6Li -> 3He + 6Li; two-body reverse kinematics 6Li + 3He -> 8B + 1n; elastic scattering reverse kinematics 6Li + 3He -> 6Li + 3He. 4. What projectile energy shall we use in our measurements?

  7. 5. EXPERIMENTAL SET-UPSa) Internal options – LNL, Italyi) CN / RIPEN array DIRECT KINEMATICS • CN 3He beam can arrive up to an energy of 11 MeV (pulsed 2 ns); • Part of the RIPEN array could be used for the neutron detection • Non-coincident measurement • Li target is available • Could be considered as a test measurement

  8. 5. EXPERIMENTAL SET-UPSa) Internal options – LNL, Italyii) TANDEM / RIPEN-PHOSWICH array REVERSE KINEMATICS • TANDEM 6Li beam is available around energy of 20 MeV (pulsed ~1 ns); • The RIPEN array could be used for the neutron detection in coincidence with the PHOSWICH array for the 8B detection • The high elastic count rate is not a problem for the PHOSWICH detectors • The RIPEN array has to be equipped with the electronic modules

  9. RipeN Rivelatori per Neutroni a LNL 24 BC501 cylindrical Liquid Scintillators 12.7cm x 12.7 cm

  10. RipeN @ LNLOngoing tests 4 MeV p + Li pulsed beam @ CN Van de Graaf accelerator Acqiris: DC271A – 1GS/s – 4 Ch – 8 Bit Digital electronics: under test n g g n ToF Sampled signal g n

  11. RipeN @ LNLOngoing tests Source Tests Preliminary digitized electronics: Acqiris card Am-Be 137Cs g Am-Be n g n 60Co g • Bit- resolution • Sampling rate • Acquisition rate • PSA algorithm (developed by T. Marchi) n keVee 88Y • All 24 detectors working! • Good n-g discrimination • Light response • Discrimination threshold

  12. PHOSWICH array at LNL IMF (ZIMF from 3 up to ~12)

  13. 5. EXPERIMENTAL SET-UPSb) External options i) MAGNEX / EDEN Set-up, LNS Catania, Italy REVERSE KINEMATICS • 6Li beam is available around energy of 20 MeV (pulsed ~1 ns); • The EDEN array could be used for the neutron detection coupled to the MAGNEX array for the 8B detection • The target chamber, equipped with multiple entrance ports which are double-valved to allow rotation of the spectrometer without breaking vacuum in the chamber • The entrance position-sensitive start detector (PSD), providing the Start signal for the TOF and measuring the particle angles. • The focal plane detector (FPD), which identifies the particles. It measures ion position, direction (angle), energy-loss, charge and mass EDEN Calibration R. Ghetti et al., Nucl. Instr. and Meth. A 516 (2004) 492-501

  14. 5. EXPERIMENTAL SET-UPSb) External options ii) HYRA / NAND Set-up, IUAC New Dehli, India REVERSE KINEMATICS Hybrid Recoil Mass Analyzer (HYRA) National Array of Neutron Detectors (NAND)

  15. 5. EXPERIMENTAL SET-UPSb) External options iii) AKULINA / DEMON Set-up, JINR Dubna, Russia REVERSE KINEMATICS DEMON Neutron detection array

  16. 5. EXPERIMENTAL SET-UPSb) External options iv) JYU, Jyvaskyla, Finland DIRECT KINEMATICS

  17. 6. TARGETS The people of the LNL-EXOTIC set-up are using 3He gas targets. The composition of the target is the following: the 2.2 micron entrance HAVAR (heat treatable Cobalt base alloy that provides very high strength, Co-42%, Cr-19.5%, Ni-12.7%) window with the diameter of 16 mm, 5 cm of the gas cell, exit window with the same characteristics of the entrance one. If we decide to use 5 cm (obviously using a cooling procedure), we can just borrow one of the existing targets from the EXOTIC set-up. In case we want to use less then 5 cm, we can realize a new target with a guidance of the EXOTIC set-up users. The 3He gas targets are provided by Padova and the cost of the one is estimated to be ≤ 5 KEuro. Schematic drawing of the gas target(s)

  18. 7. CONCLUSION A. Personally we see a more feasible internal option ii) by using the RIPEN set-up at the LNL 3rd experimental hall with the detection set-up consisting of the PHOSWICH array for the 8B detection in coincidence with the neutrons detected by the RIPEN array. B. The choice of kinematics is reverse in this case, ~20 MeV pulsed 6Li beam can be provided by the LNL TANDEM accelerator and as a target 3He gas target (already existing or realized in a decent time) can be used. C.The question here is a timescale, as the RIPEN array should be equipped with electronics for 24 detection modules. D. If the timescale for the RIPEN developed is considered to be long, the internal option i) and external option i) (Catania) could get high priority.

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