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

From: Srinidhi Bheesette <srinidhi.bheesette_at_cern.ch>
Date: Tue, 6 Sep 2016 22:32:47 +0200

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-
> 7fJZTzN3LqZ7CQFLCHW2rmRCv
> > 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-
> 7fJZTzN3LqZ7CQFLCHW2rmRC
> > 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 Wed Sep 07 2016 - 01:13:00 CEST

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