Hello
I do not know what you get from the spectrometer, I can just guess a
few things
1) FLUKA does not know what is the detector resolution, coming from the
carriers statistics and electronics noise. This will surely broaden the
peaks. You can add the resolution online with a user routine called
detscw.f, enabled by what(4) in the userweig card.
2) How is exactly your source neked, deposited, with window..? Even a
small absorbing layer could greatly distort the alpha spectrum
2) There could be conversion electrons, gamma rays and x-rays from 241Am
decay. All low energy. The interaction probability of photons will be
small, but electrons could deposit energy in your Si layer. However,
with production and transport thresholds at 100 keV ( as set by the
PRECISIO sdum) those will be killed at the source position. Lowering the
threshold (EMFCUT) should help, however:
3) FLUKA does not (yet) provide CORRELATED decay radiation. With this,
I mean that electrons/photons from a given level could be emitted
together with an alpha line ending on a different nuclear level. On
average, spectra and energy will be faithfully reproduced. On
event-by-event (detect) basis, energy could be non-conserved.
4) point 3 above is true only for radioactive decays. All prompt
radiation from nuclear reactions is correlated with exact energy
conservation event by event.
Hope this helps, and happy to discuss if there is more info
Paola
On 6/21/24 11:58, angeld wrote:
> Hi, Paola!
>
> Thank you very much for your help!
>
> With this change in the comscw.f file indeed I can get a spectrum
> (please, find the attached figure). I get the same results even the
> default comscw.f file. Probably the problem is that I don't understand
> completely the picture. Is this the deposited energy just from the
> alpha particles? This spectrum is not quite what we get from the
> alpha-spectrometer. I think that my interpretation on how I should
> simulate the experiment is wrong.
>
> Best regards,
> Angel
>
> On 2024-06-19 19:33, Paola Sala wrote:
>> Hi Angel
>> apologies again for the previous answer.
>> The reason why nothing is scored in DETECT is that the condition
>> should be on
>> JTRACK
>> not on JSCRNG.
>> Jscrng identifies the detector, jtrack identifies the particle type
>>
>> Hope this helps Paola
>>
>> On 6/10/24 12:14, angeld wrote:
>>
>>> Hi Mario,
>>>
>>> I have added the USERWEIG card in the .inp file and modified the
>>> comscw.f file (please, find the .inp and .f files attached). But
>>> unfortunately I am not doing something right or I am still missing
>>> something since nothing is scored with the DETECT card.
>>>
>>> Best regards,
>>> Angel
>>>
>>> On 2024-06-07 07:36, Santana, Mario wrote:
>>>> Hi Angel,
>>>>
>>>> Here are some insights. Hopefully, they are helpful.
>>>>
>>>> * DETECT will score the energy deposition from all particles,
>>>> including all the secondaries. Yes, you can filter by particle, by
>>>> customizing the user routine “comscw.f” (in ./usermvax) and adding
>>>> the USERWEIG card to your input file.
>>>> Within the routine, the condition ISCRNG.eq.8 will apply to DETECT,
>>>> and then you can JSCRNG.eq.-6 to alphas,
>>>>
>>>> e.g.:
>>>>
>>>> IF (ISCRNG.eq.8) THEN
>>>>
>>>> COMSCW = ZERZER
>>>>
>>>> IF (JSCRNG.eq.-6) COMSCW = ONEONE
>>>>
>>>> END IF
>>>>
>>>> * I think it is OK, like the movement of charges etc. cannot be
>>>> accounted for per my knowledge. Of course, make sure your
>>>> semiconductor is made of Si, not Ge or any compound.
>>>>
>>>> * It looks OK at a first glance.
>>>>
>>>> -M
>>>>
>>>> FROM: owner-fluka-discuss_at_mi.infn.it <owner-fluka-discuss_at_mi.infn.it>
>>>> on behalf of angeld <angeld_at_inrne.bas.bg>
>>>> DATE: Thursday, June 6, 2024 at 11:37 AM
>>>> TO: fluka-discuss_at_fluka.org <fluka-discuss_at_fluka.org>
>>>> SUBJECT: [fluka-discuss]: silicon detector of alpha particles
>>>>
>>>> Dear FLUKA users and experts,
>>>>
>>>> We are trying to simulate the energy deposition of alpha particles in
>>>> Si
>>>> (please see 241Am.inp attached) and obtain the energy spectrum of the
>>>> alpha particles. As we don't complete comprehend the results I have
>>>> several questions:
>>>>
>>>> 1. Does the DETECT card score the energy deposition of all particles
>>>> (alphas, gammas, electrons, etc.) in the given region? Can we score
>>>> just
>>>> the alphas?
>>>> 2. Should we do something to account for the semiconductor nature of
>>>> the
>>>> Si or the way it is defined is fine?
>>>> 3. Should we add more cards with physical process or threshold
>>>> energies?
>>>>
>>>> Best regards,
>>>> Angel
>>>> -- This message has been scanned for viruses and
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>>>
>>
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Received on Fri Jun 21 2024 - 21:24:41 CEST