Re: [fluka-discuss]: Cross section of neutrons

From: Andrew Davis <andrew.davis_at_wisc.edu>
Date: Wed, 01 Mar 2017 02:26:51 +0000

Hi Srinidhi

There are a number of issues assuming that your input deck is representative

1) Your START card only contains a single history to run, from a single run of 1 primary you cannot make any assertions regarding the results of your calculation since you have a large statistical uncertainty. You should likely run several million histories with (at least) 5 independent random number seeds using the already established tools to perform the averaging.
2) You used a USRBIN score (with 1 bin for x-y-z) to determine the energy deposition, you might as well use a USRTRACK score, not an issue really, but I may’ve chosen a USRTRACK instead
3) Your plot doesn’t include any statistical error, its hard judge the accuracy of a Monte Carlo calculation without any mention of the statistical error.

Thanks

Andy

On Feb 28, 2017, at 4:57 PM, Srinidhi Bheesette <srinidhi.bheesette_at_cern.ch<mailto:srinidhi.bheesette_at_cern.ch>> wrote:

Hi all,

I have simulated a pixel detector (just a silicon sensor layer) in FLUKA and bombarding it with point neutron source at different energies from 1-25.5MHz with a step size of 0.5MHz. I run a single simulation.

I then score the energy deposited in the detector (one value for one run) and then plot a graph of the energy deposited on the x-axis the source energy on the y-axis shown below:

<image.png>

The energy seems to increase till 20MeV but then start fluctuating from 20.5 to 25.5MeV and also a spike at 17MeV

Am I missing some cards in my input file (attached) for activating some feature for neutron energies after 20MeV?

Please help.

Cheers,
Shri

(Srinidhi Bheesette)
<sensor-22.5MeV.inp>


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Received on Wed Mar 01 2017 - 04:41:00 CET

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