Date: Wed, 7 Mar 2018 19:03:33 +0800 (GMT+08:00)
Dear Francesc,
Thanks for your reply. I do need the event-by-event scoring, I changed the input file and ran it again, and I get the non-zero results. But there are some doubts about the output:
1) I use flair to merge the *.17 files and get the output shown in 1.png, it's a 4-column data, what's the physical meaning of each column? I guess the 1st and 2nd column are the energy bin. The 3rd data is decimals, does it stand for the relative intensity or counts? The 4th colum is the percentage error,is it? When I sum these decimals, it is not 1.0, does it mean some primaries exit the detector? Then I use the fortran subroutine to process the *.17 files and it also gives an output shown in 3.png, but the 2nd colume is integer, I guess these integers have the same meaning as the above decimals if it's divided by their sum.
2) In the DETECT card, the lower and upper limit are important to get the non-zero results, so it is important to evaluate the approximate energy deposition. In my input file, I don't define a trigger region, and thus the default WHAT(5) of DETECT card is anti-coincidence, why is that? Waht does it get rid of?
3) The data is plotted in 2.png, as we see, they show a peak, how does it formed? Whether the peak has a physical imaging?
4) I often use very small thresholds in the EMF-CUT cards because I think I will lose some information if I set a higher value. The root of the issue is how to set the threshold value, what is the standard?
5)In the input file I use EVENTBIN card, unfortunately, I don't know how to read it out? I read the manual, but I can't handle it. The manual says it's like the USRBIN. Maybe it also shows a spatial distribution. I read some articles about using FLUKA to simulate scintillator response, they often use EVENTBIN card, but I don't known how to reconstruct the response only using the EVENTBIN output, I think it's a terrible work, could you give the methods?
I look forward your reply, thanks very much!
Best regards.
Yang
> -----原始邮件-----
> 发件人: "Francesc Salvat-Pujol" <francesc.salvat.pujol_at_cern.ch>
> 发送时间: 2018-03-06 23:59:10 (星期二)
> 收件人: "YANG Tao" <yangt_at_ihep.ac.cn>
> 抄送: fluka-discuss_at_fluka.org
> 主题: Re: [fluka-discuss]: problem about the DETECT card
>
> Dear Yang,
>
> At the end of this message you will find the clarification of terms you
> asked about.
>
> Do you really need the (anti)coincidence machinery? If you just want to
> score energy deposition a USRBIN might be more comfortable. If you need
> event-by-event scoring, you can consider an EVENTBIN card.
>
> Otherwise, running your input file using Flair to conveniently merge and
> view the results from a few cycles, one obtains non-zero histograms in
> the resulting scin_17.dtc (?). Try it again in a clean directory and let
> us know in case it does not work.
>
> The DETECT card as you have it,
>
> * ..+....1....+....2....+....3....+....4....+....5....+....6....+....7..
> DETECT 0.0 1.0E-7 0.09 1E-11 scinDETEC
>
> defines (see manual) scin as the detector region, scoring energy
> deposition on an event-by-event basis using 1024 bins from 1e-7 to 9e-2
> GeV in coincidence with the trigger region (see definition/clarification
> at the end of the message). Since you have not defined a trigger region,
> the following note from the manual applies:
>
> ====
> Note: if no trigger region is given (i.e. no region with negative sign)
> a simple event-by-event scoring takes place.
> ====
>
> Thus, you are scoring event-by-event energy deposition in the scin
> region. A few additional comments on your input file:
>
> - Using DEFAULTS with SDUM=PRECISION already activates EMF. No need to
> pass the EMF card.
>
> - You define the SCIN compound, which is not used anywhere (you use the
> predefined PLASCINT in the ASSIGNMAt card). I would comment it out.
>
> - In the GLOBAL card, the first three WHATs are the default values, the
> 4th is ignored, the 5th I suspect is redundant with GEOBEGIN and
> SDUM=COMBNAME below, and the 6th is not used (see manual).
>
> - You are using terribly small thresholds in your EMF-CUT cards. Are you
> sure you need them?
>
> - Note also that the comments you have at the beginning of the input
> file and the title string do not match the rest of contents.
>
> Cheers,
>
> Cesc
>
> PS: In an attempt to briefly answer your terminology questions,
> coincidence techniques are, in a nutshell, methods for either a)
> examining spectral features that are obscured by a large background or
> otherwise affected by unwanted events, or in general b) exploiting
> correlated information from two detectors. For example, in gamma
> spectroscopy the presence of a photon background due to Compton
> scattering reduces the signal-to-background ratio of photopeaks at lower
> energies, thus progressively deteriorating the "detection ability".
>
> The coincidence trick consists in using information from 2 detectors to
> get rid of uninteresting/offending events. In the gamma-spectroscopy
> example above, the idea is to use a second detector and discard events
> which coincide/hit both detectors, thus measuring in anticoincidence.
> Conversely, in e.g. positron emission tomography (PET), one uses
> coincident hits from ~511 keV photons in two detectors to reconstruct an
> image.
>
> For these situations FLUKA has a dedicated built-in scoring estimator,
> accessible via the DETECT card. The idea is that you define a region (or
> several) as the trigger, and then another region (or several) as the
> detector. You can then do one of two things:
>
> - score events that hit both the trigger and the detector. This is a
> coincidence measurement (e.g. like in the PET example above).
>
> - discard events that hit both the trigger and the detector. This
> is an anti-coincident measurement (e.g. as in the Compton
> suppression example above).
>
> See the manual for the implied definition of "event".
>
> On Mon, Mar 05 2018, at 22:18 +0800, YANG Tao wrote:
> >
> >Hi, Dear users!
> >
> >I simulate protons incident on a plastic scintillator, and use DETECT card to obtain the energy deposition spectrum. But I only get the ZERO results in every energy bin. May be I set the wrong parameters of DETECT card, I read the manual, but I can't clearly understand the so called "trigger regions" &"detector regions", and the term "coincidence" &"anti-coincidence". Could anyone help me to point out what's wrong with my input file and explain the meaning of above terms? Thanks!
> >
> >Best regards!
> >
> >Yang
>
>
>
> --
> Francesc Salvat Pujol
> CERN-EN/STI
> CH-1211 Geneva 23
> Switzerland
> Tel: +41 22 76 64011
> Fax: +41 22 76 69474
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