Thank you Stefan for this clarification and the pointers.
Initially I thought pseudorapidity was what I required as I am assessing the beam scattering, but know I think scoring the polar angle may be more appropriate.
When scoring polar angle I was hoping to get my USRYIELD and USRBDX results to agree (to convince myself I am using them correctly) but I still haven't been able to, so I think I am misunderstanding something, but still cannot see what I would be doing wrong. When plotted on a log scale the USRYIELD results seem the most believable and vary as I would expect with target thickness and energy. But I cannot seem to get the same behaviour from USRBDX - I have obviously made a mistake somewhere.
Thank you once again, and any further guidance would be much appreciated.
Hayley
-----Original Message-----
From: Stefan Roesler [mailto:sroesler_at_mail.cern.ch]
Sent: 25 August 2014 09:11
To: Smith, Hayley (STFC,RAL,ISIS)
Cc: fluka-discuss_at_fluka.org
Subject: RE: [fluka-discuss]: USRBDX and USRYIELD
Just a minor correction to my below email: it should read "theta being the polar angle" (and not "azimuthal")
cheers
Stefan
On Fri, 22 Aug 2014, Stefan Roesler wrote:
> Dear Hayley
>
> USRYIELD/What(6) is an user-defined normalization factor; if you leave
> it empty it is assumed to be 1. It has nothing to do with What(4) of
> the continuation card which is the upper scoring limit of the second quantity.
>
> Just to be sure: do you indeed what to score USRYIELD in
> pseudorapidity, which is -ln(tan(theta/2)) (theta being the azimuthal
> angle)?? It must peak at large values (small theta) for (scattered) beam-particles.
>
> USRBDX always scores energy spectra (in your case with one energy bin
> it is a single value). In case you define several angular bins you get
> as many "spectra" as angular bins (in your case 100). If you select in
> Flair 1.x (I recommend to go to Flair 2.x) under "Det" the second option "2 1 scatter 2D"
> you will see the different values as function of angle.
>
> Cheers
> Stefan
>
>
>
> On Fri, 22 Aug 2014, hayley.smith_at_stfc.ac.uk wrote:
>
>> Thank you very much for your help Stefan, it has been much
>> appreciated - I am now able to run the deck without it crashing.
>>
>> As a follow up, you say it is important to input values for all
>> WHATs. In this case, are you able to advise what value I should put
>> for WHAT (6) of the first USRYIELD card? It says in the manual 'normalisation factor'.
>> Would this be the same as WHAT (4) in the continuation card?
>>
>> Also, I am confused by the output I get from the USRYIELD and USRBDX cards.
>>
>> I would have thought that to score the angular distribution using
>> USRYIELD that the maximum angle would be Pi/2. However when I do
>> this I get strange results. The result seems more sensible for a
>> maximum angle of 2Pi, but still I would have expected the peak of the
>> angular distribution to be around 0, rather than around 2Pi? Am I misinterpreting my results?
>>
>> With the USRBDX scoring solid angle I understand why the maximum
>> angle for this would be 2Pi. However, the results I obtain for
>> angular distribution for a single energy bin are just as confusing to me...
>>
>> I have read extensively through the manual and previous posts but
>> have not been able to find any information.
>> I understand that a difference between USRBDX and USRYIELD is that
>> USRBDX calculates the angle with respect to the normal, and USRYIELD
>> calculates the angle with respect to the beam direction (in my case).
>> Maybe this is a source of my confusion?
>>
>> Are you able to explain:
>> Why the result of USRYIELD with a maximum angle of 2Pi is centred
>> around 2Pi?
>> Why using a maximum angle of Pi/2 in USRYIELD in this case is
>> seemingly incorrect?
>> Why I am struggling to get a meaningful result from USRBDX (or
>> why/how I am misinterpreting the results)?
>>
>> My input file and three screenshots showing the resulting graphs I
>> describe are attached.
>> Any help is very much appreciated,
>> Hayley
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: Stefan Roesler [mailto:sroesler_at_mail.cern.ch]
>> Sent: 20 August 2014 09:42
>> To: Smith, Hayley (STFC,RAL,ISIS)
>> Cc: fluka-discuss_at_fluka.org
>> Subject: Re: [fluka-discuss]: USRBDX and USRYIELD
>>
>> Dear Hayley
>>
>> I recommend to enter input values for all What's in scoring cards.
>> Some have default values, some don't.
>>
>> For example in your case WHAT(4) of the USRYIELD continuation card
>> (upper limit of the second quantity) has no default (!) which causes
>> the code to crash (normalization with an undefined value..)
>>
>> Furthermore, when the upper energy limit in USRBDX and USRYIELD is
>> not defined, the code uses the beam energy. However, when scoring
>> BEAMPART the energy of the particle to be scored is exactly at the
>> bin limit, and depending on the internal rounding the particle might be scored or not.
>> Thus, I suggest you define an upper energy limit that is slightly
>> above the beam energy.
>>
>> Cheers
>> Stefan
>>
>>
>> On Mon, 18 Aug 2014, hayley.smith_at_stfc.ac.uk wrote:
>>
>>>
>>> Dear All
>>>
>>>
>>>
>>> I am trying to look at the scattering of a 800 MeV proton beam
>>> through a carbon target. (At present the beam distribution and
>>> target geometry are very much simplified).
>>>
>>> I have tried to score the angular distribution of the proton beam in
>>> two ways, using USRBDX and using USRYIELD.
>>>
>>>
>>>
>>> I thought USRYIELD would be the most appropriate since I read
>>> various threads on the forum, and this one in particular seemed to
>>> be doing a very similar thing to me,
>>> http://www.fluka.org/web_archive/earchive/new-fluka-discuss/0568.htm
>>> l
>>>
>>>
>>>
>>> However, when I try to create a USRYIELD card with a single energy
>>> bin the progress status for the run always ends after the first
>>> cycle with ?Finished with ERRORS? and nothing stands out to me from
>>> the .log, .out or .err files.
>>>
>>>
>>>
>>> When I don?t use a USRYIELD card the USRBDX card outputs results,
>>> however I am unsure how to interpret them in terms of beam
>>> scattering or divergence.
>>>
>>> The relevant files are attached for your information.
>>>
>>>
>>>
>>> Is anyone able to advise me on how best to score the beam divergence
>>> through the target?
>>>
>>> Is my approach correct? What is causing the run to finish with
>>> errors (that I can?t seem to find in the output files)?
>>>
>>>
>>>
>>> Thanks, any assistance is much appreciated,
>>>
>>> Hayley
>>>
>>>
>>>
>>>
>>>
>>> Hayley Smith
>>>
>>>
>>>
>>> Accelerator Physicist
>>>
>>> ISIS Facility
>>>
>>> Rutherford Appleton Laboratory
>>>
>>> Harwell Oxford
>>>
>>> OX11 0QX
>>>
>>>
>>>
>>> 01235 445524
>>>
>>> hayley.smith_at_stfc.ac.uk
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Scanned by iCritical.
>>>
>>>
>>>
>>>
>>
>> --
>> Scanned by iCritical.
>
--
Scanned by iCritical.
- application/octet-stream attachment: muons.inp
Received on Fri Aug 29 2014 - 17:11:13 CEST