Date: Wed, 29 Oct 2014 04:39:37 +0800 (GMT+08:00)
Hi Paola,
Thanks for your replay,sorry for my vague description .The material inside the detector is LS(liquid scintillant),outside of the detector is vacuum,no rock.I counted the number of neutrons that produced in the detector,and divided the number by (total muon track length in detector * density of LS).
I have activated photonuclear reaction and radioactive decays.I got your opinions,because of the small size these particles (gamma neutron) escape from the detector before they produce new neutrons.It made so big influece more than that I thought before .
Thanks!
Dengjie
-----Original Messages-----
From: "paola sala" <paola.sala_at_cern.ch>
Sent Time: Wednesday, October 29, 2014
To: lidengjie <lidengjie_at_ihep.ac.cn>, fluka-discuss <fluka-discuss_at_fluka.org>
Cc:
Subject: Re: [fluka-discuss]: yield of muon induced neutron and size of detector
Hello,
may I ask you two things? First, how do you calculate the "neutron yield" ? Second, what do you have in your geometry? The detector alone or also the rock around?
The explanation I can guess is that if you look at neutron flux or interactions in the detector, when the detector is small many neutrons will escape, while in a large detector they will build up a cascade. In addition, neutrons will also be produced through photonuclear interactions by photons whenever the muons produce electromagnetic showers, and also in this case particles will escape from small detectors. One should try to reproduce the experimental conditions, activate photonuclear interactions by photons, and take into account also the surrounding materials, where particles can be produced and reach the detector, and neutrons can be reflected back into it.
.Hope this helps
Paola
On 10/28/2014 02:32 PM, lidengjie wrote:
Hi fluka experts,
Recently,I did muon simulations in underground neutrion experiment using fluka.
I'm confused that the yield of muon induced neutron is related to size of the detector,or we can say that it's related to the average track length of muon,the following table is the result I have tested with different sizes of detector.I want to know whether this result is reasonable or not ,and if there is a CARD that can control this.
| average track length of muon （cm） | neutron yield when muon's kenetic energy is 260GeV
/u/(g cm^-2) | neutron yield when muon's kenetic energy is 56GeV
/u/(g cm^-2) | |
| 5000 | 18*10^-5 | 7.43*10^-5 | |
| 650 | 18*10^-5 | 6.74*10^-5 | |
| 350 | 13*10^-5 | 5.6*10^-5 | |
| 310 | 10*10^-5 | | |
| 212 | 8.9*10^-5 | 5*10^-5 | |
| | | |
|
Here is the result from KamLand neutrino experiment.
Best regards,
Li Dengjie
IHEP
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