Re: [fluka-discuss]: some questions about charged particle transport

From: Giuseppe Battistoni <>
Date: Mon, 25 Nov 2013 09:59:43 +0100

Dear Chen Yuan
> When I learn charged particle transport,There are a few problems I cannot understand.The questions are as followings.
> (1)The Fluka course said "Accurate PLC (not the average value but sampled from a distribution), giving a complete independence from step size",I cannot understand this sentence at all. What kind of the distribution is? Could you give me a simple interpretations?

I advice to study the paper (quoted in FLUKA references):
A. Ferrari et al., Nucl. Instr. Meth. in Phys. Res. B71, 412-426 (1992)
and references therein

> (2)In the Fluka course,you refer to the validity conditions of Moliere theory more
  than once. But, what are the validity conditions of Moliere theory? Could you tell me in detail?

Any multiple scattering therory applies when in a given step you have several coulomb scattering.
Several is a qualitative word. In practice, as a rule of thumb, you may be safe
if you expect many tens of scatterings.

> (3)In the Fluka course,you mentioned "full single scattering are used to handle very low energy electron problems and very thin layers problems. But,how much low is the electron energy? How much thin are the layers?
> In a word,I want to know when I should use mutiple scattering and when I should use the full single scattering.
> I'm looking forward to receive from you.Thanks for your time.Thanks for your reply.

We advice single scattering only when you have thickness of materials so small that the above
conditions risks to be not respected.
A couple of practical examples:
- layers of nuclear photographic emulsions.
where you aim to measure charged tracks with few micron accuracy
- very thin layers of silicon trackers (order of 100 micron or less)

        Best regards
                Giuseppe Battistoni

INFN Milano
via Celoria 16, 20133 Milano, Italy
tel: +39 02 50317307
fax: +39 02 50317617
Received on Mon Nov 25 2013 - 11:02:12 CET

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