Re: [fluka-discuss]: What particle crosses a boundary

From: Joseph Comfort <Joseph.Comfort_at_asu.edu>
Date: Sun, 2 Mar 2014 01:02:56 -0700 (MST)

Mario,

In BXDRAW, I accumulate an array indexed by JTRACK, and print it out at
the end through usrout. By the way, all of the particles of proton or
gamma beams (which do not decay) cross the boundary without loss or extra
particles, even though they enter a region of copper and can have
interactions. (I also make an array for particles that leave the target,
and those produced by interactions show up in it.)

Joe


On Sat, 1 Mar 2014, Santana, Mario wrote:

> Joseph,
>
> Within mgdraw.f are you sure your particle printing statements are in
> BXDRAW?
>
> Mario
>
>
> On 3/1/14 3:23 PM, "Joseph Comfort" <Joseph.Comfort_at_asu.edu> wrote:
>
>> I sometimes use boundary crossings as a means to identify the particle
>> that reached a boundary (detector). There are some problems.
>>
>> The setup is very simple: A line beam of 1-GeV/c particles travel 2000
>> cm
>> in vacuum before hitting a square 'target'. The target has either copper
>> or vacuum. Mgdraw is used to select on particle crossings from the
>> vacuum _into_ the target, and each particle type is recorded.
>>
>> 100,000 pi+ beam on 1-cm-thick copper: 72,835 particles enter the
>> target.
>> That is OK. In addition to pi+, mu+, and 2 e+, there are 9 photons and 5
>> pi-. How can pi+ decays produce photons and pi- in vacuum? (The vacuum
>> target gives only pi+ and mu+.)
>>
>> 1 million K0Long beam on 5-cm-thick copper: 542,355 particles enter the
>> target. They include e-, e+, gamma, mu+, mu-, K0, and K0bar (also true
>> for vacuum target). But there are also 26 protons and 38 neutrons!
>> How can a K0L produce a p or n in vacuum?
>>
>> It appears that JTRACK does not identify the particle that hit and
>> crossed
>> the boundary, but rather something after interactions somewhere in the
>> medium. In the case of several produced particles, which one is chosen?
>>
>> How can the particle that hit the boundary be identified?
>>
>> Joe Comfort
>>
>
>
Received on Sun Mar 02 2014 - 10:15:33 CET