Date: Tue, 6 Sep 2016 11:57:01 +0200
Hi Francesco,
Thanks for the reply.
After reading some papers I found out that the thickness of the
metallization layer is 4 microns.
[image: 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.
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-
> 7fJZTzN3LqZ7CQFLCHW2rmRCv1k1H6H0?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-
> 7fJZTzN3LqZ7CQFLCHW2rmRCv
> > > 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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(image/png attachment: image.png)