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First Results from the 8 B Production Experiment at LNL

First Results from the 8 B Production Experiment at LNL. VLADIMIR KRAVCHUK and MARCO CINAUSERO. FP7 WP4, Beta Beam Meeting, Napoli, 21.10.2011. CONTENTS. INTRODUCTION CROSS-SECTION MEASUREMENTS AND PRECISION THEORETICAL CALCULATIONS 8 B PRODUCTION EXPERIMENT AT LNL DATA ANALYSIS

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First Results from the 8 B Production Experiment at LNL

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  1. First Results from the 8B Production Experiment at LNL VLADIMIR KRAVCHUK and MARCO CINAUSERO FP7 WP4, Beta Beam Meeting, Napoli, 21.10.2011

  2. CONTENTS • INTRODUCTION • CROSS-SECTION MEASUREMENTS AND PRECISION • THEORETICAL CALCULATIONS • 8B PRODUCTION EXPERIMENT AT LNL • DATA ANALYSIS • VERY PRELIMINARY RESULTS • CONCLUSIONS AND OUTLOOK

  3. 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: C. Rubbia et al., Nucl. Instr. and Meth. A 568 (2006) 475-487

  4. INTRODUCTION • FUNDAMENTAL QUESTIONS • ABSOLUTE CROSS SECTION WITH HIGH PRECISIONMEASURED EXPERIMENTALLY • ANGULAR DISTRIBUTIONMEASURED EXPERIMENTALLY • THEORETICAL CROSS SECTION CALCULATIONS IN THE WIDE ENERGY RANGE

  5. CROSS SECTION MEASUREMENTS AND PRECISION MYSTERY OF THE6Li(3He,n)8BREACTION AT LOW ENERGIES POSITRON COUNTING TECHNIQUE NEUTRON TIME-OF-FLIGHT TECHNIQUE ≠

  6. CROSS SECTION MEASUREMENTS AND PRECISION C.R. McCLENAHAN and R.E. SEGEL Phys. Rev. C 11 (1975) Page 376 (!)

  7. CROSS SECTION MEASUREMENTS AND PRECISION • FUNDAMENTAL CONCLUSIONS • PREVIOUS EXPERIMENTS USING TWO DIFFERENT TECHNIQUES PRODUCED VERY DIFFERENT RESULTS IN TERMS OF THE 8B PRODUCTION CROSS SECTION VARYING BY ≈ A FACTOR OF 3 • EXPERIMENTAL ERRORS ARE QUITE LARGE AND VARYING IN THE RANGE FROM15 TO 20% • THE AIM OF THE PRESENT WORK IS TO CLARIFY THESE POINTS BYPERFORMING AN ACCURATE HIGH-STATISTICS MEASUREMENT OF THE 8B PRODUCTION CROSS SECTION AND ANGULAR DISTRIBUTION

  8. THEORETICAL CALCULATIONS Figure 2. Differential cross section calculations for E=10 MeV (blue) and E=5.6 MeV (black) are shown together with the experimental data at E=5.6 MeV. The experimental errors vary from 10 to 30%. Figure 1. Differential cross section calculations for E=5.6 MeV are presented together with the experimental data. Different renormalized LSJ-components and the sum are shown. THEORETICAL CALCULATIONS WERE PERFORMED IN COLLABORATION WITH PROF. S.A. GONCHAROV (THEOR. DEP., MOSCOW STATE UNIVERSITY). THEORETICAL CODE DWUCK4 USING ZR-DWBA (ZERO RANGE DISTORTED WAVE BORN APPROXIMATION) WAS USED FOR THE DIFFERENTIAL CROSS SECTIONS CALCULATIONS. SEE THE PROPOSAL FOR THE DETAILS.

  9. 8B PRODUCTION EXPERIMENT AT LNL 7 MV CN accelerator (14-28 june, 2011) 6.0 MeV 3He+ + 6Li  8B + n Neutron angular distribution measurement PMT Philips XP2041 EMI 9823B active area 12.7 cm 12.7cm 2 m Flight path DW= 2.95 mSr Dq= ± 2.5o 8 BC501 detectors covering angles from 15o to 140o in LAB

  10. 8B PRODUCTION EXPERIMENT AT LNL 6LiF (500 mg/cm2) on Au (500 mg/cm2) Background measurements: 1)7LiF (500 mg/cm2) on Au (500 mg/cm2), 2)12C (70 mg/cm2) & 3) without target DE (15 mm) – E (200 mm) Silicon Telescope Spectrum on-line 3He Rutherford scattering of the beam on the Au backing used as normalization to determine the 8B production absolute cross section 1H

  11. 8B PRODUCTION EXPERIMENT AT LNL 2 V1720 digitizer from CAEN (12 bit, 250 MS/s) in the 8 channels VME version communicating with a standard PC via a VME bridge (CAEN V1718). Digitizers + bridge The software used for acquisition is a customized version of CAEN WaveDump, able to handle and synchronize two or more digitizers. Three different kinds of information are expected to be obtained processing the scintillator signals: the energy release of the impinging particle, its time of flight and the pulse shape discrimination between neutrons and gammas. Data are processed using algorithms able to perform RC/CR filters and CFD emulator. A proper baseline subtraction is computed from the raw data Ancillary NIM electronics HV System Waveforms collected in binary format are later unpacked into ROOT Trees for the following analysis.

  12. DATA ANALYSIS SANREMO Monte Carlocode calculations, M. Barbui (Texas A&M) It is absolutely necessary to perform FLUKA calculations with threshold 150 keVee, G. Collazuol (Nov. 2011)

  13. DATA ANALYSIS ENERGY LEVEL SCHEME OF 8B

  14. DATA ANALYSIS NEUTRON-GAMMA DISCRIMINATION ZERO-CROSSING METHOD GATE APPLIED IN THE DATA ANALYSIS n g 150 keVee

  15. DATA ANALYSIS NEUTRON-GAMMA DISCRIMINATION GATE g NO GATE GATE n

  16. DATA ANALYSIS BACKGROUND SUBTRACTION 5.75 MeV 3He+ + 6Li  8B + n, R1(15o LAB), Run 11715 Counts 8Bg.s. Sensitive Nonlinear Iterative Peak (SNIP) clipping algorithm 12C(3He, n)14O 8B* 6Li(3He,np)7Be 9B* g 9Bg.s. ToF, ns

  17. DATA ANALYSIS PEAK IDENTIFICATION DUE TO THE REACTION ON 12C 5.75 MeV 3He+ + 6Li  8B + n, R1(15o LAB), Run 11715 6.0 MeV 3He+ + 12C  14O + n,R1(15o LAB), Run 11738 Counts 8Bg.s. 12C(3He, n)14O 8B* ToF, ns

  18. DATA ANALYSIS NEUTRON TIME-OF-FLIGHT SPECTRA 5.75 MeV 3He+ + 6Li  8B + n, R1(15o LAB) - R4(39o LAB), Run 11715 8Bg.s. 8Bg.s. Counts Counts 15o 23o 12C(3He, n)14O 12C(3He, n)14O 8B* 8B* g g ToF, ns ToF, ns 8Bg.s. 8Bg.s. Counts Counts 31o 39o 12C(3He, n)14O 12C(3He, n)14O 8B* 8B* g g ToF, ns ToF, ns

  19. DATA ANALYSIS NEUTRON TIME-OF-FLIGHT SPECTRA 5.75 MeV 3He+ + 6Li  8B + n, R5(50o LAB) – R8(140o LAB), Run 11715 8Bg.s. 8Bg.s. Counts Counts 50o 80o g 12C(3He, n)14O 12C(3He, n)14O g 8B* 8B* ToF, ns ToF, ns Counts Counts g 110o g 140o 12C(3He, n)14O 12C(3He, n)14O 8Bg.s. 8Bg.s. ToF, ns ToF, ns

  20. DATA ANALYSIS LISE++ KINEMATICS SIMULATION

  21. VERY PRELIMINARY RESULTS RUN 11715, ≈ 1/20 OF THE FULL STATISTICS

  22. CONCLUSIONS AND OUTLOOK • CONCLUSIONS • WE HAVE PERFORMED HIGH-STATISTICS EXPERIMENT MEASURING ABSOLUTE CROSS SECTION AND ANGULAR DISTIBUTION OF 8B USING NEUTRON TIME-OF-FLIGHT TECHNIQUE • PRELIMINARY RESULTS SHOW A CROSS SECTION VALUE HIGHER THAN THOSE CONSIDERED IN THE RUBBIA PAPER OBTAINED USING POSITRON COUNTING TECHNIQUE • PRELIMINARY RESULTS ARE IN AGREEMENT WITH THE THEORETICAL DWBA CALCULATIONS AND WITH OLDER EXPERIMENTAL RESULTS OBTAINED USING THE SAME TIME-OF-FLIGHT TECHNIQUE • THE DISAGREEMENT BETWEEN THE OLD EXPERIMENTAL DATA AND DWBA CALCULATIONS CAN BE EXPLAINED WITH A WRONG EVALUATION OF THE DETECTION EFFICIENCY FOR LOW ENERGY NEUTRONS • FOR THE FIRST TIME THE ABSOLUTE CROSS SECTION AND ANGULAR DISTRIBUTION OF THE FIRST EXCITED STATE OF 8B HAS BEEN MEASURED • OUTLOOK • TO COMPLETE THE ANALYSIS – BEGINNING 2012 • TO PERFORM DWBA CALCULATIONS FOR HIGHER BEAM ENERGIES – BEGINNING 2012 • TO PREPARE SCIENTIFIC PUBLICATIONS – SPRING 2012 • NEED TO PERFORM AN EXPERIMENT AT HIGHER BEAM ENERGIES – ?

  23. SPECIAL THANKS TO: FABIANA GRAMEGNA (Design, mounting, shifts) TOMMASO MARCHI (PSD, On-line analysis, TTree, shifts) GIANMARIA COLLAZUOL (Data Acquisition, shifts) VALENTINO RIGATO (CN Accelerator Scientific Coordinator) LUCA MARAN (CN Accelerator Operation) LORENZO PRANOVI (CN Accelerator Operation) ALESSANDRO MINARELLI (Mechanics) MASSIMO LORIGGIOLA (Targets) SELVINO MARIGO (Cooling system) AURIGA Group, INFN and University of Padova (3He) ALEXANDER GONCHAROV (DWBA Calculations) GIANFRANCA DE ROSA (Shifts and discussions) VITTORIO PALLADINO

  24. DATA ANALYSIS 6Li(3He,n)8B reaction Counts ToF, ns THIS WORK 1 run (≈1/20 whole statistics) U. Fasoli et al., Nuovo Cimento 37(1965)249 whole statistics

  25. DATA ANALYSIS BACKGROUND SUBTRACTION 5.8 MeV 3He+ + 6Li  8B + n, R8(140o LAB), Run 11715 Counts 6Li(3He,np)7Be g 12C(3He, n)14O 8Bg.s. ToF, ns

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