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Study of 12 C Fragmentation at TWAC ITEP.

Study of 12 C Fragmentation at TWAC ITEP. B.M.Abramov, Yu.A.Borodin, S.A.Bulychjov, I.A.Dukhovskoy, A.I.Khanov A.P.Krutenkova , V.V.Kulikov, M.A.Martemianov, M.A.Matsyuk, E.N.Turdakina. ITEP, Moscow. Outlook Introduction Motivation Experiment Data analysis Conclusion.

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Study of 12 C Fragmentation at TWAC ITEP.

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  1. Study of12C Fragmentation at TWAC ITEP. B.M.Abramov, Yu.A.Borodin, S.A.Bulychjov, I.A.Dukhovskoy, A.I.Khanov A.P.Krutenkova, V.V.Kulikov, M.A.Martemianov, M.A.Matsyuk, E.N.Turdakina. ITEP, Moscow Outlook Introduction Motivation Experiment Data analysis Conclusion RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  2. ITEP Accelerator Facility TWAC A.P.K.is indepted to N.N.Alekseev for providing the ITEP Accelerator Facility diagram RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009..

  3. Motivation for nuclear fragmentation study 1. Measurement of nuclear composition of secondary beams at ITEP heavy ion accelerator. 2. Precise measurement of high energy fragment spectra for a) search for cumulative effect in fragment production in heavy ion collisions, b) test of theoretical models in the unstudied region of high momentum. 3. Now systematic data are needed as input to transport codes for radiotherapy with heavy ions, for shielding calculation for long-duration space missions and for RIB design RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  4. Experimental set up 10m 16m 16m С-12 θ С А В Monitor -- thin foil Be-target Scintillation counters А 3(TOF+dE/dx) + H(20x10) B 2(TOF+dE/dx) Trigger = 1A x 1B C 14(TOF) 0.6x2.0 mxm -- bending magnet -- quadrupole 12C + Be -> p ( d, t, 3He, 4He, 6He, 8He,… ) + X θ = 3.5O T=301.6 MeV/nucleon (p=0.879 GeV/c/nucleon) RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009. .

  5. Beam channel: rigidity P/Z=1.2 GeV/c/Z The fragment clusters are clearly seen and can be easily separated RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  6. Beam channel: rigidity 1.2 GeV/c/Z Good charge separation at low Z. RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  7. T=600 MeV/nucleon Beam channel: rigidity P/Z= 4.75 GeV/c/Z 8He can be easily separated RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  8. Relative yield, d2σ/(dΩdP/P) in lab, of H and He isotopes Relative yield Rigidity =P/Z, GeV/c The isotopic composition of the beam RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  9. Main statements of fragmentation statistical model. A.S.Goldhaber, PL 53B, 306 (1974) D.E.Greiner et al. PRL 35, 152 (1975) T. Odeh et al. PRL 84, 4557 (2000) • In the rest frame of the nucleus a fragment momentum • distribution is of gauss shape, identical for longitudinal • and transversal directions. • 2. Parabolic law for rms of momentum distributions • σF2= σ02 AF (A – AF)/(A–1), AF(A) is the mass number • of the fragment (projectile nucleus). • Limiting fragmentation hypothesis. Fragmentation properties • are independent of projectile energy and target mass. RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  10. Triton momentum distribution in projectile rest frame. Fit with Gaussian. Linear scale Log scale χ 2 /ndf = 15.3/21 χ 2 /ndf = 45.1/31 σ = 162±3 MeV/c RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  11. Proton and deuteron momentum distributions in projectile rest frame. Fit with Gaussian from -0.2 to 0.2 GeV/c. σ = 75±3 MeV/c σ = 121±5 MeV/c Cumulative Cumulative Gaussian Gaussian RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  12. 3He and 4He momentum distributions Ed3σ/d3p, relative units He-3 He-4 σ = 149±3 MeV/c σ = 148±3 MeV/c RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  13. 6He and 8He momentum distributions Ed3σ/d3p, relative units He-6 He-8 σ = 174±9 MeV/c σ = 187±7 MeV/c RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  14. Comparison of σF with data of D.E.Greiner et al. σF2 = σ02 AF(A – AF)/(A – 1) Fragment T = 0.3 GeV/n 1.0 GeV/n ( this exp.) (Greiner et al.) σ0 , MeV/c p 75.1±3.1 64±4 75.1±3.1 d 121.8±4.5 112±11 90.3±3.3 t 162.0±2.5 162±14 103.4±1.5 3He 148.9±2.9 132±14 95.0±1.7 4He 136.1±3.2 125±3 86.8±1.9 6He 186.6±7.3 142±20 103.1±4.2 8He 174.3±8.8 ------- 102.1±5.3 90 Mev/c (Goldhaber) RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  15. Test of Goldhaber parabolic law This experiment – 0.3 GeV/n Greiner et al.- 1 GeV/n σ0 = 94±1 MeV/c χ2/ndf =96/6 σ0 = 74±2 MeV/c χ2/ndf =20/5 , AF Qualitative agreement with the experimental data, only RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  16. Temperatures from slope parameters. Ed3σ/d3p ~ ASexp(-T/Ts) + ACexp(-T/Tc) TS = 5.7±0.7 MeV TC = 23.0±1.5 MeV Forward ->|<- Backward RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  17. Temperatures from slope parameters. Ed3σ/d3p ~ ASexp(-T/Ts) + ACexp(-T/Tc) TS = 6.2±0.6 MeV TC = 13.5±1.0 MeV Forward ->|<- Backward RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  18. Temperatures from slope parameters. Ed3σ/d3p ~ ASexp(-T/Ts) + ACexp(-T/Tc) TS = 4.3±0.4 MeV TC = 11.5±2.1 MeV Forward ->|<- Backward RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  19. Comparison with the data on Au+Au->p+X at 1000MeV/n T. Odeh et al. (ALADIN, GSI,2000). Our data for C+Be at 300MeV/n -

  20. Comparison with ALADIN data Au+Au at 1000MeV/n Our data for C+Be at 300MeV/n - (0 – 200 MeV for P )

  21. Temperature from slope parameter at 300 MeV/nucleon. • At T<20 MeV Ts =5-6 MeV and is equal to • σF2/MF, where σF is rms of momentum • distribution. • 2. At T >50 MeV Tc = 23.5 MeV for protons • and 13.5 MeV for deuteron are in reasonable • agreement with GSI data at 1000 MeV/n • (26 and 16 MeV, respectively). RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  22. Comparison with the data for cumulative protons from V.B.Gavrilov, G.A.Leksin ITEP-128-89. M.H.Anikina et al. Phys.At.Nucl. 43, 1217 (1986) pA C+Be This Exp. Au+Au Odeh 2000 C+C Anikina 1986 RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

  23. CONCLUSION • 1. Yield of Hydrogen and Helium isotopes was measured in • C+Be collisions at 300 MeV/nucleon with high precision covering up to 6 orders of magnitude in cross section. • 2. For proton and deuteron the transition from gaussian shape typical for fragmentation from thermodynamic equilibrium to exponential shape typical for cumulative processes was observed. • 3. The calculated Ts and Tc for p, d and 4He are in reasonable agreement with available data for HI collisions. • There are not enough HI data to reliably obtain an energy dependence of Tc. RAS Nucl. Phys. Div. Meeting: “Physics of Fundamental Interactions” Nov. 26, 2009.

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