Re: blastmc Wire Chamber thresholds

From: Douglas Hasell (hasell@MIT.EDU)
Date: Mon Jan 14 2002 - 13:40:35 EST


Hi,

        I think we will have to wait for real data. Then we can tune the
Monte Carlo threshold to give a realistic rate based on our experiences
operating the chamber.

        In principle the wire chambers will detect a single electron if it
makes it from the creation point to the sense wire where the avalanche
occurs. The theshold for ionizing a gas molecule is about 4 eV so I expect
this means virtually anything created in GEANT can produce a signal. How
many X-rays, etc. are produced and how many are shielded against or
deflected by the magnetic field (for charged particles) will just have to
be seen.

--On Monday, January 14, 2002 12:48 PM -0500 Timothy Smith
<tim_smith@MIT.EDU> wrote:

>
> Hello Sean,
>
> As you say, the monte carlo for the chambers fires on
> any charged particle which passes through it. Even if you set
> energy loss to zero the chambers will fire. This could be changed
> in wc_hits.f - require that DE > threshold, but that is not the
> way it presently works. Would wire chamber people like to adress
> this?
>
> Tim
>
>
> On Mon, 14 Jan 2002, Sean Stave wrote:
>
>> Hello Blasters:
>>
>> This is a question for Tim about blastmc wire chamber thresholds. From
>> looking through wc_hits, it appears that anything other than a gamma will
>> trigger the chamber wires. However, where is the chamber threshold set?
>> Is it just handled by the standard energy cutoff parts of GEANT or is
>> there a separate setting? Thanks.
>>
>> -Sean Stave
>>
>>
>
> --
> ____________________________________________________________________
> Timothy Paul Smith Research Scientist
> MIT Bates Lab tim_smith@mit.edu
> 21 Manning Rd. tel: (617) 253-9207
> Middleton, MA 01949 fax: (617) 253-9599
>

                                                  Cheers,
                                                          Douglas

26-415 M.I.T. Tel: +1 617 258 7199
77 Massachusetts Avenue Fax: +1 617 258 5440
Cambridge, MA 02139 E-mail: hasell@mit.edu



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