RE: [fluka-discuss]: changing particle weight

From: Eleftherios Skordis <>
Date: Mon, 3 Sep 2018 08:44:51 +0000

Dear Shirley,

By reducing the weight of particles you are basically reducing the "effect" of these particles to your calculated values.

I.e. if you reduce a particle's weight by a factor of 2 (to 0.5) then you also reduce it's registered energy deposition by the same factor.

I would guess that is why in your comparison there is a slope of 2:1 with your expected values.
So in principle if you just multiply the fluka values by 2 your values should check out.

Hope this helps

Kind regards



Eleftherios Skordis
CH-1211 GENEVA 23

OFFICE: +41-22-7679541<tel:%2B41-22-7675461>
From: [] on behalf of Shirley Li []
Sent: 01 September 2018 06:09
Subject: [fluka-discuss]: changing particle weight

Dear FLUKA users,

I'm simulating particle propagation in liquid argon. I want to implement an effective "detector threshold". So, in the example attached below, in usrmed.f, I change the weight of protons below 10 MeV from 1 to 0.5, so I can study energy deposition above and below thresholds.

However, I notice that for these protons that have 0.5 weight, their quenched energy depositions don't seem to be correct. In mgdraw.f, I record energy deposition by protons, both DTRACK and DTQUEN. I thought I can calculate DTQUEN from DTRACK for each track, by etrack --> dE/dx --> quenching factor from Birk's law. This checks out for all tracks with weight 1, but doesn't for all tracks with weight 0.5. See attached figure where I compare DTQUEN and my calculated quenched energy deposition. I also attached the output from mgdraw.f.

Are there any problems changing particle weight this way? Or did I misunderstand how DTQUEN is calculated?

Thank you very much!


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Received on Mon Sep 03 2018 - 12:05:34 CEST

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