Re: [fluka-discuss]: Scoring alphas in FLUKA using USRBIN

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Wed, 7 Sep 2016 23:32:50 +0200

Hi Shri,

thermal neutrons cannot generate any proton on lithium, the (n,p) channel
opens above 3 MeV neutron energy.

Ciao

Francesco

**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. ++41 22 7678962
fax ++41 22 7668854

On Wed, 7 Sep 2016, Srinidhi Bheesette wrote:

> Hi Francesco,
> Yes I see more yield of alphas depositing their energy on the silicon sensor
> after reducing the thickness of the metallization layer.
>
> I wish to also see if I capture any protons on the silicon with the Lithium
> conversion layer. Do I need to enable any special cards for the same or I
> can simply select the PART in the USRBIN as protons and run the simulations?
>
> Inline images 2
>
> Thanks in advance. 
>
> Cheers,
> Shri
>
> (Srinidhi Bheesette)
>
> On 6 September 2016 at 22:32, Srinidhi Bheesette
> <srinidhi.bheesette_at_cern.ch> wrote:
> Hi Francesco,
> Yeah hopefully I should be able to see more alphas on the silicon
> detector now.
>
> And yes! I have now figured out a way to get the range.
>
> Thanks for your continued support. :)
>
> Cheers,
> Shri
>
> (Srinidhi Bheesette)
>
> On 6 September 2016 at 20:22, Francesco Cerutti
> <Francesco.Cerutti_at_cern.ch> wrote:
>
> Well, 4 micron change definitely the picture, since alphas
> above 1 MeV can
> make it.
>
> At the NIST link, you have just to select the material,
> click on Submit,
> and you will get a table giving stopping power and range
> (you care about
> the latter) as a function of the alpha kinetic energy.
> Units are for mass
> length, so you need to rescale them by the material
> density
>
> Best wishes
>
> Francesco
>
> **************************************************
> Francesco Cerutti
> CERN-EN/STI
> CH-1211 Geneva 23
> Switzerland
> tel. ++41 22 7678962
> fax  ++41 22 7668854
>
> On Tue, 6 Sep 2016, Srinidhi Bheesette wrote:
>
> > Hi Francesco,
> > Thanks for the reply.
> >
> > After reading some papers I found out that the thickness
> of the
> > metallization layer is 4 microns. 
> >
> > Inline images 1
> > I hope this thickness is enough for the alphas to
> penetrate through the
> > Aluminium metallization layer and reach the Silicon
> layer.
> >
> > Also I can figure out how to evaluate stopping power on
> the link you sent
> > me. Please help. Thanks in advance.
> >
> >[f18dQhb0S7ks8dDMPbW2n0x6l2B9gXrN7sKj6v4f9HlVRYvr-7fJZTzN3LqZ7CQFLCHW2rmRCv
>
> >
> 1k1H6H0?si=4558345310568448&pi=4742b69d-2ceb-47ec-e936-8e9eb633db44]
> >
> > Cheers,
> > Shri
> >
> > (Srinidhi Bheesette)
> >
> > On 5 September 2016 at 13:07, Francesco Cerutti
> <Francesco.Cerutti_at_cern.ch>
> > wrote:
> >
> >       Hi Shri
> >
> >       with 20 micron Al, likely you will not see
> anything again, since
> >       5 MeV
> >       alphas can just make it (only if travelling in the
> good
> >       direction) and
> >       your alphas are indeed less energetic.
> >
> >       Kind regards
> >
> >       Francesco
> >
> >       **************************************************
> >       Francesco Cerutti
> >       CERN-EN/STI
> >       CH-1211 Geneva 23
> >       Switzerland
> >       tel. ++41 22 7678962
> >       fax  ++41 22 7668854
> >
> >       On Mon, 5 Sep 2016, Srinidhi Bheesette wrote:
> >
> >       > Hi Francesco, 
> >       >
> >       > I am sorry, yes, I mean now I can score on the
> conversion
> >       layer. 
> >       >
> >       > Thanks for the link, its really useful. 
> >       > Just for a test I ran a job by assigning vacuum
> to the
> >       metalization layer and I observed
> >       > that I am able to score on the silicon sensor as
> well. I will
> >       now try to assign it
> >       > Aluminum again, reduce the thickness to 20
> microns and run
> >       again.
> >       >
> >       > Thanks very much for your help. :) 
> >       >
> >       >
> >       >
> >      >[f18dQhb0S7ks8dDMPbW2n0x6l2B9gXrN7sKj6v4f9HlVRYvr-7fJZTzN3LqZ7CQFLCHW2rmR
> Cv
> >       1k1H6H0?si=4
> >       >
> 558345310568448&pi=aaa52f34-4cc8-45d7-d851-b4047fa205b2]
> >       >
> >       > Cheers,
> >       > Shri
> >       >
> >       > (Srinidhi Bheesette)
> >       >
> >       > On 4 September 2016 at 21:59, Francesco Cerutti
> >       <Francesco.Cerutti_at_cern.ch> wrote:
> >       >
> >       >       Dear Shri,
> >       >
> >       >       I'd guess from the context of your message
> that you
> >       actually meant "I am
> >       >       NOW [rather than NOT] able to score
> alphas(4-He) on the
> >       conversion layer"
> >       >       and I'd be happy for that.
> >       >       About the fact that the generated alphas
> do not make the
> >       silicon detector,
> >       >       it looks indeed logical due to
> metalization: a 5 MeV
> >       alpha - more
> >       >       energetic than what you get out of thermal
> neutron
> >       capture on 6Li - has a
> >       >       range of 20 micron in aluminum, as you can
> see on NIST
> >       >     
> >     
>   (http://physics.nist.gov/PhysRefData/Star/Text/ASTAR.html).
> >       >
> >       >       Cheers
> >       >
> >       >       Francesco
> >       >
> >       >     
>  **************************************************
> >       >       Francesco Cerutti
> >       >       CERN-EN/STI
> >       >       CH-1211 Geneva 23
> >       >       Switzerland
> >       >       tel. ++41 22 7678962
> >       >       fax  ++41 22 7668854
> >       >
> >       >       On Sun, 4 Sep 2016, Srinidhi Bheesette
> wrote:
> >       >
> >       >       > Hi Francesco,
> >       >       > Thank you very much for you reply.
> >       >       > I have made the necessary changes and I
> am not able to
> >       score alphas(4-He)
> >       >       on
> >       >       > the conversion layer. But I still don't
> get any hits
> >       on the Silicon
> >       >       detector
> >       >       > layer which is separated from the
> conversion layer
> >       (Lithium) by a 40
> >       >       microns
> >       >       > metalization layer made of Aluminium
> (sorry I did not
> >       mention this in my
> >       >       > previous mail).
> >       >       >
> >       >       > Is the metalization a problem or do I
> need to make
> >       more changes so that it
> >       >       I
> >       >       > can score on Silicon too?
> >       >       >
> >       >       > Thanks in advance.
> >       >       >
> >       >     [f18dQhb0S7ks8dDMPbW2n0x6l2B9gXrN7sKj6v4f9HlVRYvr-7fJZTzN3LqZ7CQFLCHW2rmR
> C
> >       v
> >       >       >
> >     
>  1k1H6H0?si=4558345310568448&pi=d2713f3f-ab03-475e-a465-69e4fbc8836d]
> >       >       >
> >       >       > Cheers,
> >       >       > Shri
> >       >       >
> >       >       > (Srinidhi Bheesette)
> >       >       >
> >       >       > On 3 September 2016 at 13:12, Francesco
> Cerutti
> >       >       <Francesco.Cerutti_at_cern.ch>
> >       >       > wrote:
> >       >       >
> >       >       >       Hi Shri,
> >       >       >
> >       >       >       please read the manual, LOW-NEUT
> card, Note 5.
> >       >       >
> >       >       >       In particular, you need to have
> pointwise
> >       treatment activated
> >       >       >       (which is
> >       >       >       already the case for PRECISIO
> defaults) as well
> >       as a LiF
> >       >       >       compound
> >       >       >       definition containing explicitly
> the LITHIU-6
> >       material as
> >       >       >       elemental
> >       >       >       component. The latter has to be in
> turn defined
> >       by a MATERIAL
> >       >       >       card
> >       >       >       specifying monoisotopic
> composition (see again
> >       the manual and
> >       >       >       avoid the
> >       >       >       usual mistake mixing up the mass
> number in
> >       WHAT(6) - which is
> >       >       >       what you
> >       >       >       have to fill, with the number 6.0
> - and the
> >       atomic weight in
> >       >       >       WHAT(2) - not
> >       >       >       to be filled at all -).
> >       >       >
> >       >       >       Note in addition that your
> PART-THR card makes
> >       no sense, since
> >       >       >       1eV is
> >       >       >       patently not an option as
> transport threshold,
> >       being 1keV the
> >       >       >       hard cutoff
> >       >       >       for everything but neutrons and
> photons.
> >       >       >       And, as a general rule, do not
> limit the full
> >       transport to
> >       >       >       4-HELIUM only,
> >       >       >       as you did with IONTRANS, rather
> let it be
> >       applicable to all
> >       >       >       heavy
> >       >       >       and light ions (put HEAVYION, i.e.
> particle code
> >       -2, as
> >       >       >       explained in the
> >       >       >       manual).
> >       >       >
> >       >       >       Best
> >       >       >
> >       >       >       Francesco
> >       >       >
> >       >       >     
> >     
>   **************************************************
> >       >       >       Francesco Cerutti
> >       >       >       CERN-EN/STI
> >       >       >       CH-1211 Geneva 23
> >       >       >       Switzerland
> >       >       >       tel. ++41 22 7678962
> >       >       >       fax  ++41 22 7668854
> >       >       >
> >       >       >       On Sat, 3 Sep 2016, Srinidhi
> Bheesette wrote:
> >       >       >
> >       >       >       > Hi all,
> >       >       >       > I wish to score alphas produced
> by the
> >       reaction of thermal
> >       >       >       neutron( 0.025eV)
> >       >       >       > with Lithium Fluoride moderator.
> >       >       >       >
> >       >       >       > I am using a 0.025eV neutron
> point source for
> >       my simulations
> >       >       >       and scoring the
> >       >       >       > a silicon detector which is
> bonded to the
> >       moderator. 
> >       >       >       > I have enabled the transport
> using the
> >       following card
> >       >       >       >
> >       >       >       > IONTRANS    4-HELIUM
> >       >       >       >
> >       >       >       >
> >       >       >       > and also changed the threshold
> to 1eV for
> >       alphas using the
> >       >       >       following card: 
> >       >       >       >
> >       >       >       > PART-THR      -1.E-9  4-HELIUM  
>              
> >                 0.0
> >       >       >       >
> >       >       >       >
> >       >       >       > Finally I score the flux on the
> moderator
> >       using the following
> >       >       >       card:
> >       >       >       >
> >       >       >       >
> >       >       >       > USRBIN           10.  4-HELIUM  
>     22. 
> >       0.700067  0.880124  
> >       >       >        
> >       >       >       > -0.10convalp
> >       >       >       >
> >       >       >       > USRBIN     -0.702433   -0.5261  
>   -0.11     
> >       256. 256.     
> >       >       >         
> >       >       >       >
> >       >       >       > 1. &
> >       >       >       >
> >       >       >       >
> >       >       >       > and on the silicon detector
> using the
> >       following card:
> >       >       >       >
> >       >       >       >
> >       >       >       > USRBIN           10.  4-HELIUM  
>     29. 
> >       0.700067  0.880124  
> >       >       >       0.10sialph
> >       >       >       >
> >       >       >       > USRBIN     -0.702433   -0.5261 
>   -0.096     
> >       256. 256.       
> >       >       >       1. &
> >       >       >       >
> >       >       >       >
> >       >       >       > But in vain, as I do not see any
> alpha
> >       particles scored. The
> >       >       >       fort files are
> >       >       >       > filled all with zeros.
> >       >       >       >
> >       >       >       > Please let me know where I am
> going wrong.
> >       Help would be
> >       >       >       greatly
> >       >       >       > appreciated.
> >       >       >       >
> >       >       >       > Thanks in advance. 
> >       >       >       >
> >       >       >       > Cheers,
> >       >       >       > Shri
> >       >       >       >
> >       >       >       > (Srinidhi Bheesette)
> >       >       >       >
> >       >       >       >
> >       >       >
> >       >       >
> >       >       >
> >       >       >
> >       >
> >       >
> >       >
> >       >
> >
> >
> >
> >
>
>
>
>
>

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Received on Thu Sep 08 2016 - 01:01:17 CEST

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