From: Vassili Maroussov <Vassili.Maroussov_at_cern.ch>

Date: Mon, 12 Apr 2010 09:53:23 +0200

Date: Mon, 12 Apr 2010 09:53:23 +0200

Dear Anna,

thank you so much for a comprehensive reply. I need the corrected for

quenching energy deposition in MGDRAW; I'm using the following solution

for the moment:

1) In USERDUMP with SDUM=UDQUENCH Birks setting parameters B1=A/2,

B2=0, here A is the only parameter of Wright's parametrization;

2) comparing quenched and non-quenched values extra extracting A*dE/dX

and so obtaining the quenched value for Wright's parametrization.

Best regards,

Vassili

On 04/12/2010 01:11 AM, Anna Ferrari wrote:

*> Dear Vassili,
*

*>
*

*> the treatment of the quenching is implemented in FLUKA, up to
*

*> now, only following a second order Birks parametrization.
*

*> In this case it can be set directly in the input card.
*

*>
*

*> You want to use the Wright parametrization, that foresees only one
*

*> parameter (eq.5 in the Kolb article): even if this is the case, I think
*

*> that it's useful to briefly remind, first, how to proceed in the case of
*

*> a correction 'a la Birk'. This could help to better address a solution in
*

*> your case.
*

*>
*

*> In general the quenching correction must be applied at two different
*

*> levels:
*

*>
*

*> a) to the binned energy, that is scored via USRBIN or EVENTBIN:
*

*> in this case you use the TCQUENCH card (see the manual);
*

*> b) in the track reconstruction, to the deposited energy along the track:
*

*> in this case you have to use the USERDUMP card, with sdum=UDQUENCH;
*

*> what(2) and what(3) will be the first and the second Birks parameters,
*

*> in g/(MeV cm2) (see the manual also in this case).
*

*>
*

*> As I understood, the two corrections are absolutely independent: if you
*

*> are interested only to score the track variables, you can also not to use
*

*> the first card.
*

*> Let'see, now, how to retrieve the quenched values in the case b).
*

*> In mgdraw.f you have to save the corrected values both along the track
*

*> steps and for a "spot" deposition, that means:
*

*> 1) in MGDRAW, by doing the sum of the 'quenched' depositions along the
*

*> track. Instead of summing the original energy depositions dtrack(k)
*

*> (with k=1,...mtrack) you have to sum the corresponding quenched
*

*> values, that are simply given by the dtquen(k,1) output variable of the
*

*> QUENMG routine (the second number refers to the fact that you can load
*

*> more than one set of parameters, here I refer to the set 1).
*

*> The routine above is called because the setting as in b) forced the
*

*> LQEMGD variable to be .TRUE.
*

*>
*

*> 2) in ENDRAW, by considering, in the same way, the value of dtquen(1,1)
*

*> (here the first 1 means that we have only one "spot" deposit)
*

*> instead of the value of the variable 'rull'.
*

*>
*

*> Let's come, now, to your correction. First of all: QUENMG is not a user
*

*> routine and you cannot modify it.
*

*> You can think to act on the energy deposits: you don't activate the
*

*> quenching via USERDUMP and you apply your correction BOTH to the dtrack(k)
*

*> energy depositions in MGDRAW and to the 'rull' spot deposition in ENDRAW.
*

*> BUT: while the first correction is (maybe) easy to do, I have doubts about
*

*> the meaning of the second one (maybe the authors can hlp us). What I know
*

*> is that the treatment of the quenching in case of spot depositions
*

*> is not trivial to compute, because we have always to do assumptions,
*

*> depending of the kind of spot. For example a spot can be due:
*

*> - to particles under the transport thereshold (dE/dx is in this case set to
*

*> the remaining energy);
*

*> - to residual nuclei recoils (dE/dx is inthis case rescaled
*

*> from the corresponding value, of a proton of the same energy);
*

*> - to charged particles generated from low energy interactions, that are not
*

*> in general transported (they are transported only for interactions
*

*> on hydrogen and few others): in this case dE/dx corresponds to their
*

*> production energy; .....
*

*>
*

*> For this kind of complexity, I don't know if a meaningful correction
*

*> can be done simply in ENDRAW...
*

*>
*

*> Hope it helps,
*

*> Anna
*

*>
*

*>
*

*>
*

*>> Dear FLUKA experts,
*

*>>
*

*>> I wanted to implement the quenching parametrization proposed by N.R.Kolb
*

*>> et al (NIM-A 368, 1996, pp.745-749), but didn't find where I can get
*

*>> dE/dx (or, what is equivalent, the "energy deposition length") for each
*

*>> energy deposition. What common is used by QUENMG?
*

*>>
*

*>> Regards,
*

*>>
*

*>> Vassili
*

*>>
*

*>> P.S.: Actually the parametrization I want to use is proposed by
*

*>> G.T.Wright,
*

*>> Phys. Rev. 91 (1953) 1282.
*

*>>
*

*>>
*

*>>
*

*>
*

*>
*

Received on Mon Apr 12 2010 - 13:53:12 CEST

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