1. Prospects to measure 8 B production VLADIMIR KRAVCHUK Laboratori Nazionali di Legnaro, Italy EUROnu week in Strasbourg 1-4 June 2010

2. CONTENTS 1.INTRODUCTION 2.CROSS-SECTION MEASUREMENTS AND PRECISION 3.ANGULAR DISTRIBUTION 4.DIRECT OR REVERSE KINEMATICS? 5.EXPERIMENTAL SET-UPS a) Internal options: LNL-TANDEM/CN, Legnaro i) LNL - CN ii) LNL – TANDEM RIPEN+PHOSWICH SET-UP iii) LNL – TANDEM EXOTIC+RIPEN SET-UP b) 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 6.TARGETS 7.CONCLUSION

3. 1. INTRODUCTION In the article of Rubbia et al. the 8 B nucleus is considered as a neutrino source producing relatively high- energy neutrinos: The reaction proposed for the 8 B 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 3 He 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( 3 He)=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 3 He (16 MeV 6 Li) – intermediate case; 2) 10 MeV 3 He (20 MeV 6 Li) – optimum energy according to the articles of Rubbia et al. and Neuffer; 3) 5.5 MeV 3 He (11 MeV 6 Li) – 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 3 He + 6 Li -> 8 B + 1 n; elastic scattering direct kinematics 3 He + 6 Li -> 3 He + 6 Li; two-body reverse kinematics 6 Li + 3 He -> 8 B + 1 n; elastic scattering reverse kinematics 6 Li + 3 He -> 6 Li + 3 He. 4. What projectile energy shall we use in our measurements?

10. 5. EXPERIMENTAL SET-UPS a) Internal options – LNL, Italy i) CN / RIPEN array DIRECT KINEMATICS -CN 3 He 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

11. 5. EXPERIMENTAL SET-UPS a) Internal options – LNL, Italy ii) TANDEM / RIPEN-PHOSWICH array REVERSE KINEMATICS -TANDEM 6 Li 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 8 B 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

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

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

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

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

16. 5. EXPERIMENTAL SET-UPS b) External options i) MAGNEX / EDEN Set-up, LNS Catania, Italy REVERSE KINEMATICS - 6 Li 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 8 B detection -The target chamber, equipped with multiple entrance ports which are double-valved to allow rotation of the spectrometer without breaking vacuum in the chambertarget chamber -The entrance position- sensitive start detector (PSD), providing the Start signal for the TOF and measuring the particle angles.position- sensitive start detector -The focal plane detector (FPD), which identifies the particles. It measures ion position, direction (angle), energy-loss, charge and massfocal plane detector EDEN Calibration R. Ghetti et al., Nucl. Instr. and Meth. A 516 (2004) 492-501

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

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

19. 5. EXPERIMENTAL SET-UPS b) External options iv) JYU, Jyvaskyla, Finland DIRECT KINEMATICS

20. 6. TARGETS The people of the LNL-EXOTIC set-up are using 3 He 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 3 He 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)

21. 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 8 B detection in coincidence with the neutrons detected by the RIPEN array. B. The choice of kinematics is reverse in this case, ~20 MeV pulsed 6 Li beam can be provided by the LNL TANDEM accelerator and as a target 3 He 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.