Pauli-blocking effects in neutron-alpha reactions

Conference · Wed Jun 01 04:00:00 EDT 1994

OSTI ID:10173578

Avrigeanu, M ^[1]; Avrigeanu, V ^[1]; Antonov, A N ^[2]; Chadwick, M B ^[3]; Hodgson, P E ^[4]; Stoitsov, M V ^[2]

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1. Institutul de Fizica si Inginerie Nucleara, Bucharest (Romania)
2. Inst. of Nuclear Research and Nuclear Energy, Sofia (Bulgaria)
3. Lawrence Livermore National Lab., CA (United States)
4. Oxford Univ. (United Kingdom)

We present a knockout model for direct (n,{alpha}) reactions in which the residual nucleus is left in a continuum excited state. The interaction of the neutron with a preformed alpha particle inside the nucleus is related to the free neutron-alpha scattering cross-section, with modifications to account for nuclear medium effects, including Fermi motion, Pauli-blocking, and barrier penetration. Phase space restrictions for the four nucleons of the alpha-particle after the knockout are imposed by a Pauli-blocking function. We apply this model, along with evaporation contributions, to analyze excitation functions of (n,{alpha} reactions on {sup 48}Ti, {sup 51}V, {sup 52}Cr, {sup 54}Fe, {sup 55}Mn, and {sup 59}Co. Good agreement is obtained between our calculations and experimental measurements. Values for the local Fermi energy in the region from where knockout occurs indicate a surface reaction.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 10173578
• Report Number(s): UCRL-JC--117463; CONF-940507--36; ON: DE94016358
• Country of Publication: United States
• Language: English

Related Subjects

662340
663430
663540
663550
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
A = 39-58
A = 59-89
ALPHA PARTICLES
COBALT 59 TARGET
EXCITATION FUNCTIONS
HADRON INTERACTIONS
IRON 54 TARGET
NEUTRON REACTIONS
NUCLEON-INDUCED REACTIONS AND SCATTERING
NUCLEON-NUCLEON INTERACTIONS
SCATTERING
VANADIUM 51 TARGET