Proton Spallation: Info on Energy, Reactions & Alpha Particles

[nlanky85]

Howdy folks,
i have read that high energy protons striking a target nucleus (say silicon) can produce neutrons through spallation. Can someone point me to some literature, that gives the following details.

1) What energy neutrons are produced for a given input proton energy
2) Probabilities of a nuclear reaction as opposed to ionisation loss for incident protons
3) What happens if the incident protons are replaced with alpha particles

I am interested in proton energies ranging from 10 MeV - 100 GeV.

Thanks guys.

 

[Bob S]

Spallation neutron sources tend to be high-Z targets, like tungsten, mercury, or lead. The U.S. Spallation Neutron Source (SNS) uses 1 GeV protons on mercury, the European ESS is still optimizing their design. See

http://accelconf.web.cern.ch/AccelConf/IPAC10/papers/mopea078.pdf

The ESS is using the CERN program GEANT4 for determining the neutron yield and spectrum. See

http://geant4.cern.ch/

and

http://geant4.cern.ch/support/index.shtml

Bob S

 

[nlanky85]

Thanks Bob S

 

[Bob S]

This article ("Spallation Neutron production Measurements" by Zucker et. al) from Brookhaven National Laboratory (open "Quick view") compares experiment and theory for the number of spallation neutrons produced for various energy protons on tungsten and lead targets, and finds about 17 neutrons per GeV in lead, and about 20 neutrons per GeV in tungsten.

http://docs.google.com/viewer?a=v&q...UtqxOs&sig=AHIEtbTsGlVAHbm6a3lSe_rYQiFOG4YlHg

See Fig 6 and Table 1.

[added] The yields per GeV plateau between 1 and 2 GeV, and drop off at higher energies due to pion production.

Bob S