Average multiplicities of particles emitted in the h-a reactions

Transcription

1 Average multiplicities of particles emitted in the h-a reactions Aatos Heikkinen Geant4 Hadronic Physics Working Group Meeting October 22, 2007 Group Meeting, October 22nd, 2007 Average multiplicities of particles emitted in the h-a reactions 1/9

2 Talk Outline Outline This 10 talk introduces some references providing data for a average multiplicities of particles emitted in the h-a reactions. The aim is to provide benchmarking material for evaluating Geant4 hadronic physics models, and gain insight to physical aspects of particle multiplicity. Group Meeting, October 22nd, 2007 Average multiplicities of particles emitted in the h-a reactions 2/9

3 Multiplicity references Data for h-a reaction particle multiplicity Very few direct particle multiplicity measurements, < M >, have been done, but we can infer < M > from measured total production cross-section, typically with uncertainty factor of 2. We proceed by providing some references, following the order of the publication year: Measurements on neutron multiplicities in coincidence with light charged particle [Dufauquez et al., 2006]. Comparison between particle multiplicities predicted by ABLA and GEM for p(2.5 GeV)+ 197 Au, p(1 GeV)+ 208 Pb, and p(1.2 GeV)+ 208 Pb. Splitting to INC and evaporation components is done and the exitation energy E at the end of the cascade stage is given [Boudard et al., 2004]. Group Meeting, October 22nd, 2007 Average multiplicities of particles emitted in the h-a reactions 3/9

4 Multiplicity references Multiplicity distributions of emitted n, H, and He for p(2.5 GeV) + Au and multiplicities as a function of exitation energy. Average multiplicities, separating direct, < M > direct =< M > total < M > evaporated, and evaporated component are given [Letourneau et al., 2002]. Manifestation of the trawling effect (reduction in nuclear density behind a fast-moving particle) in average multiplicity for p( GeV)-A at photoemulsion experiments, distinguishing particle classification: shower- (E π > 80 MeV, E p > 500 MeV), gray- (15 < E π < 80 MeV, 30 < E p < 500 MeV), black- (E π < 15 MeV, E p < 30 MeV, lightest nuclei d, t, α), and heavy-particles [Iljinov et al., 1994]. Group Meeting, October 22nd, 2007 Average multiplicities of particles emitted in the h-a reactions 4/9

5 Multiplicity references Experimental data and MICRES Monte Carlo of < M > π +/event as a function of < M > p for incident π + of 4 GeV on Be, Cu and Ta targets [Ackerstaff et al., 2002]. Neutron and light particle multiplicities, as predicted by Liège cascade, with two different evaporation models for p(1 GeV)+Pb, and p(1.2 GeV)+Pb. Case p(1.8 GeV)+Au also includes experimental data [Boudard et al., 2002]. Neutron yields from p(12 GeV)+Pb as a unit of of the number of neutron per incident proton (n/p). Experimental data shown as a function of benchmark target bar length, and compared with NMTC/JAM and LCS2.7 models [Niita et al., 2001]. < M > p and < M > n Monte Carlo data for p( MeV)+ 208 Pb / 90 Zr comparing various pre-equilibrium models [Lara, 1999]. Group Meeting, October 22nd, 2007 Average multiplicities of particles emitted in the h-a reactions 5/9

6 Multiplicity references Multiplicities < n >, < p >, < d >, < t >, < 3 He >, and < α > in INC + evaporation / pre-equilibrium / percolation models for the p(800 MeV)+Pb system [Cugnon et al., 1997]. References presented for various particle multiplicity experiments [Cugnon, 1996]. Group Meeting, October 22nd, 2007 Average multiplicities of particles emitted in the h-a reactions 6/9

7 References References Ch. Dufauquez et al. Light charged particle and neutron production in proton- and α-particle-induced reactions on nat Si at energies between 20 and 65 MeV. Nuclear Physics, A 773 (2006) A. Boudard et al. A new model for production of fast light clusters in spallation reactions. Nuclear Physics A 740 (2004) A. Letourneau et al. Composite-particle emission in the reaction p+au at 2.5 GeV. Nuclear Physics A 712 (2002) Group Meeting, October 22nd, 2007 Average multiplicities of particles emitted in the h-a reactions 7/9

8 References K. Ackerstaff et al. A hadron-nucleus collision event generator for simulations at intermediate energies. NIM A 491 (2002) A. Boudard et al. Intranuclear Cascade model for a comprehensive description of spallation reaction data. DAPNIA/SPHN and Phys. Rev. C 66 (2002) K. Niita et al. High-energy particle transport code for NMTC/JAM. NIM B 184 (2001) Group Meeting, October 22nd, 2007 Average multiplicities of particles emitted in the h-a reactions 8/9

9 References V. Lara Pre-equilibrium and equilibrium decays. Unpublished, 21 September J. Cugnon Improved intranuclear cascade model for nucleon-nucleus interactions. Nuclear Physics A 620 (1997) J. Cugnon Spallation reactions. Ecole Internationale Juliot-Curie de Physique Nucleaire, 15 eme session, 9 14 Septemre A.S. Iljinov et al. Intermediate-Energy Nuclear Physics. Nuclear Physics, CRC Press, pp Group Meeting, October 22nd, 2007 Average multiplicities of particles emitted in the h-a reactions 9/9