[mcstas-users] mcstas-users Digest, Vol 25, Issue 3

Sun Feb 23 15:12:15 CET 2014

Hi, I need just example about the specter of reflectivity of a
polariser supermirror (by reflexion and by transmission) and
monochromator

2014-02-06 7:36 UTC, mcstas-users-request at mcstas.org
<mcstas-users-request at mcstas.org>:
> Send mcstas-users mailing list submissions to
> 	mcstas-users at mcstas.org
>
> To subscribe or unsubscribe via the World Wide Web, visit
> 	http://mailman.mcstas.org/cgi-bin/mailman/listinfo/mcstas-users
> or, via email, send a message with subject or body 'help' to
> 	mcstas-users-request at mcstas.org
>
> You can reach the person managing the list at
> 	mcstas-users-owner at mcstas.org
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of mcstas-users digest..."
>
>
> Today's Topics:
>
>    1. Re: Fwd: Neutron Beam tracking - MCSTAS (Britt Rosendahl Hansen)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 5 Feb 2014 09:28:12 +0000
> From: Britt Rosendahl Hansen <broh at fysik.dtu.dk>
> To: Mar?a Freir?a L?pez <m.freiria87 at gmail.com>
> Cc: "mcstas-users at mcstas.org" <mcstas-users at mcstas.org>
> Subject: Re: [mcstas-users] Fwd: Neutron Beam tracking - MCSTAS
> Message-ID: <764BA851-9CFB-4FD1-A19A-0FF60BC9170A at fysik.dtu.dk>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi Maria
>
> I think you could use the premonitor_nd and monitor_nd components to get the
> answer you need. I suggest looking at these components in the component
> manual.
>
> Feel free to write me again if you cannot get it to work.
>
> Regards,
> Britt
>
>
> Sent from my iPhone
>
>> On 05 Feb 2014, at 09:50, "Mar?a Freir?a L?pez" <m.freiria87 at gmail.com>
>> wrote:
>>
>>
>> Hello everybody,
>>
>> my name is Mar?a Freir?a, Master Student in Nuclear Engineering at the
>> Technische Universit?t M?nchen. Right now I am working at my Master Thesis
>> at the research reactor FRM II, studying the viability of a future fuel
>> conversion.
>>
>> The fact is that we did some experiments at the reactor in order to
>> measure the cold neutron spectrum for different reactor power levels.
>>
>> Here is a brief description of the reactor:
>>
>> <Beam_tubes.jpg>
>> Several beam tubes supply various experimental stations with neutrons from
>> different parts of the reactor. In our experiment we considered the tube
>> SR-1 (connected to the cold source), which is subdivided into 6 smaller
>> tubes as shown in the figure above.
>>
>> One of these 6 tubes (NL-4) is again divided into 2 tubes (named NL-4a and
>> NL-4b) which lead to the 2 stations (SANS-1 and PGAA) where the measures
>> were taken:
>>
>> <Experiment_Scheme_1.jpg>
>>
>>
>>
>> The obtained results concerning neutron spectrum at the 2 stations differ
>> from each other. Eventhough the neutrons in both tubes come from the cold
>> source, based on the results, we think that the neutrons have a different
>> nature, due to the heterogeneous properties along the cold source. A point
>> to be taken into account is the fill level  of the cold source (D2 -
>> liquid deuterium aprox. 25K). Some experts suggest that the major part of
>> the neutron flux analyzed at SANS-1 comes from the lower part of the cold
>> source and in the case of PGAA the neutrons have their origin in the upper
>> part of the tank (near the fill level). This would explain the different
>> results at the 2 stations:
>>
>> <Experiment_Scheme_2.jpg>
>>
>> In order to proof this theory, we started to work with MCSTAS.
>>
>> I got the instruments and components defined in MCSTAS which describe the
>> geometry of the tube structure. But, as a beginner, I need to ask for some
>> help:
>>
>> I need to know the origin of the neutrons which enter the tubes NL-4a and
>> b. In other words: from which part of the cold source do most of the
>> neutrons come in each case (NL-4a and NL-4b):
>>
>> <Experiment_Scheme_3.jpg>
>>
>> Is it true that the neutron spectrum is different at the 2 experimental
>> stations because the beam has its origin in different parts (the lower and
>> the upper part) of the cold source? Or is the distribution almost
>> homogeneous so that the beam properties in both tubes should be the same?
>>
>>
>> In order to answer these questions, the suggestion made is to implement a
>> kind of "marker" at the beginning of SR-1 divided in "n" cells. This would
>> make it possible to know which of these neutrons "make their way" to
>> SANS-1 and which others to PGAA.
>>
>> Is it viable to create such a "marker"? Or do you have any other
>> suggestions for solving this problem?
>>
>> As I said, as a beginner I am not conscious of the possibilities that
>> MCSTAS offers, that is why I was directed to you by Peter Link, Neutron
>> Optics department at the FRM II.
>>
>> I hope I could explain my problem in a more or less understandable way :)
>>
>> I would be really greatfull for your help!
>>
>> Kind regards,
>>
>> Mar?a
>>
>> _______________________________________________
>> mcstas-users mailing list
>> mcstas-users at mcstas.org
>> http://mailman.mcstas.org/cgi-bin/mailman/listinfo/mcstas-users
> -------------- next part --------------
> A non-text attachment was scrubbed...
> Name: Experiment_Scheme_2.jpg
> Type: image/jpeg
> Size: 50905 bytes
> Desc: Experiment_Scheme_2.jpg
> URL:
> <http://mailman.mcstas.org/pipermail/mcstas-users/attachments/20140205/c6fada5a/attachment.jpg>
> -------------- next part --------------
> A non-text attachment was scrubbed...
> Name: Experiment_Scheme_3.jpg
> Type: image/jpeg
> Size: 5965 bytes
> Desc: Experiment_Scheme_3.jpg
> URL:
> <http://mailman.mcstas.org/pipermail/mcstas-users/attachments/20140205/c6fada5a/attachment-0001.jpg>
> -------------- next part --------------
> A non-text attachment was scrubbed...
> Name: Experiment_Scheme_1.jpg
> Type: image/jpeg
> Size: 38312 bytes
> Desc: Experiment_Scheme_1.jpg
> URL:
> <http://mailman.mcstas.org/pipermail/mcstas-users/attachments/20140205/c6fada5a/attachment-0002.jpg>
> -------------- next part --------------
> A non-text attachment was scrubbed...
> Name: Beam_tubes.jpg
> Type: image/jpeg
> Size: 95723 bytes
> Desc: Beam_tubes.jpg
> URL:
> <http://mailman.mcstas.org/pipermail/mcstas-users/attachments/20140205/c6fada5a/attachment-0003.jpg>
>
> ------------------------------
>
> _______________________________________________
> mcstas-users mailing list
> mcstas-users at mcstas.org
> http://mailman.mcstas.org/cgi-bin/mailman/listinfo/mcstas-users
>
>
> End of mcstas-users Digest, Vol 25, Issue 3
> *******************************************
>