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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Received on Sun Sep 04 2016 - 23:28:00 CEST