|Message: Re: Underestimation of neutron yield for Be^9(p,n) at low proton energies (~2-5 MeV)||Not Logged In (login)|
Click on the Forum title, e.g. on the "Forums by Category" page, to read a sequence of postings to the Forum and its threads all in one page. If you are only interested in one thread or the thread following a specific posting, click the thread or the posting, which takes you to a smaller page, which contains only the part you are interested in and may be easier to navigate.
Messages are "chained" if there are only replies at the first level, i.e. 1/1.html, 1/1/1.html etc. In case of "chained" messages the message number is replaced by the icon and there is no indentation.
Inline: Display the subject line only or also the text of the posting(s); for the choice "All" the "Outline" choices are switched off.
|1||0||1||no text / full text of posting|
|2||1||All||text for level 1 only / text for All postings|
Outline: Choose the depth of the posting thread, successive toggle controls provide increasing detail.
|1||2||1||2 levels / 1 level (original posting)|
|2||3||2||3 levels / 2 levels|
|3||3||All||3 levels / all levels (all postings)|
On Mon, 20 Nov 2017 16:55:04 GMT, Alessandro Tentori wrote:
> Hello, > > I'm simulating neutron production via Be^9(p,n) reaction. > > In the simulations, a flux of monoenergetic protons impinges on a > beryllium target. I'm interested in low proton energies (from 2 MeV to 5 > MeV). > > I tried several PhysicsLists: QGSP_BERT_HP G4HadronPhysicsFTFP_BERT_HP > G4HadronPhysicsQGSP_BERT_HP G4HadronPhysicsQGSP_BIC_HP > G4HadronPhysicsINCLXX > > I noticed that neutron yield is always underestimated by several orders > of magnitude ( ~ 10^-3 !). > > For instance, according to experimental data in: Howard, W. B., Grimes, > S. M., Massey, T. N., Al-Quraishi, S. I., Jacobs, D. K., Brient, C. E., > & Yanch, J. C. (2001). Measurement of the thick-target 9Be (p, n) > neutron energy spectra. Nuclear science and engineering, 138(2), > 145-160. > > I should obtain 1 neutron every 10^4 protons, while in my simulations I > have 1 neutron every 10^7 protons. > > Underestimation of neutron yield is a known issue in the literature, > however, according to > > Edgecock, T. R., Cywinski, R., Barlow, R. J., Bungau, A., & Ratcliffe, > N. (2012). Optimising Neutron Production From Compact Low Energy > Accelerators. In Conf. Proc. (Vol. 1205201, No. IPAC-2012-THPPR076, pp. > 4154-4156). > > using QGSP_BERT_HP it should be possible to reproduce experimental data > reliably, at least for Beryllium converters. > > I�ve tried to implement the setup described in this work, but I still > get an underestimation of a factor of ~10^-3 . > > Is there a way to correct this problem? > > Any help would be greatly appreciated. > > Best regards > > Alessandro Tentori >
I ran example Hadr03 with attached macro for the 3 families : Bertini, BinaryCascade, INCL (see Hadr03/src/PhysicsList.cc). Outputs in attachement.
If you want results with elastic collisions included, remove the command /process/inactivate hadElastic
Attachment: http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2017/11/21/08.17-81738-Be9.mac.txt http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2017/11/21/08.17-80430-bertini.out.txt http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2017/11/21/08.17-33068-bic.out.txt http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2017/11/21/08.17-59355-incl.out.txt
|Inline Depth:||Outline Depth:||Add message:|