Re: ions gaining momentum?

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Fri, 26 Nov 2010 11:28:22 +0100

Dear Makis,

> But the momentum of the outgoing (11,6)C particles seems to be
> higher than the momentum of the incoming (11,6)C particles. Could this
> be correct?

no, in fact ions do not accelerate through a material layer (both in
reality and in FLUKA!)

Be careful: the value you input in the BEAM card is the ion momentum per
nuclear mass unit (defined as the 12C *nucleus* mass divided by 12), what
you print in mgdraw is instead the ion momentum per nucleon, which turns
out to be higher since the 11C excess mass is positive. In other words,
C11 has 11 nucleons (as from DBLE(IONA)) and a mass of 11.0111613 nmu (as
from DBLE(IONA)+EXMSAZ(DBLE(IONA),DBLE(IONZ),.TRUE.,IZDUM)*EMVGEV/AMUC12)

Note that the manual states erroneously that for ions energy and momentum
are intended PER UNIT ATOMIC MASS (defined as the 12C *atom* mass divided
by 12)

Cheers

Francesco

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

On Wed, 24 Nov 2010, Chrysostomos Valderanis wrote:

> Hello,
>
> I have the following problem. An ion beam (6,11)C is hitting a copper
> target and I am writing out the momentum of the particles passing the
> boundary. But the momentum of the outgoing (11,6)C particles seems to be
> higher than the momentum of the incoming (11,6)C particles. Could this
> be correct?
>
> Thank you in advance,
> Makis
>
> ps. The above is correct just for the 1cm target. for longer targets
> momentum is lower.
>
Received on Fri Nov 26 2010 - 12:07:29 CET

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