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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Received on Tue Mar 06 2018 - 18:30:02 CET