Re: USRYIELD to look at photon emittance?

From: Mina Nozar <>
Date: Mon, 14 Nov 2011 10:53:34 -0800

Dear Francesco,

Hello and thank you so much for your help. I have fixed the two problems and am now seeing a reasonable distribution
for the photon polar angular distribution.

Just to make sure, is the region selection for USRYIELD the same as for YSRBDX? ie. Two consecutive regions sharing a
boundary with first region the upstream region and the second the downstream region?

I have attached a slice (XZ view with beam along Z) of the simple converter/target geometry for an electron beam on
molten lead converter and photons on the dUC3Gr target.

To look at the photon emittance on the dUC3Gr target, I have used the upstream Tantalum window as Reg. 1 and dUC3Gr as
Reg. 2. Is this the best choice?

With best wishes,

On 11-11-10 08:13 AM, Francesco Cerutti wrote:
> Dear Mina,
> USRYIELD can indeed give you the angular distribution of the photons
> crossing the boundary surface between two regions, as a function of the
> polar angle defined with respect to the beam direction (or a different
> direction if you specify it by a further USRYIELD card with SDUM=BEAMDEF).
> However in your input there are two errors:
> i. if you set WHAT(1)=114.0, the angle values are expected to be input in
> radians. WHAT(7)=180.0 is then wrong, unless you choose WHAT(1)=124.0.
> ii. WHAT(12) is not intended only for the specific purposes you recall
> (actually of no interest for you) but also for choosing the output
> quantity. What you want is the plain double differential yield (like most
> of the people using USRYIELD), so you must set WHAT(12)=3.0 and not to
> leave the default (which involves the beam electron cross section in a
> given material, making no sense)
> Hope this helps
> Francesco
> **************************************************
> Francesco Cerutti
> CH-1211 Geneva 23
> Switzerland
> tel. ++41 22 7678962
> fax ++41 22 7668854
> On Thu, 10 Nov 2011, Mina Nozar wrote:
>> Dear all,
>> I am trying to look at the emittance of the photons emerging from a molten Lead converter placed in front of a target
>> for 50 MeV electron beam with a 7.5 mm width.
>> Can I use USRYIELD to look at the angular distribution of the photons?
>> I used this USRYIELD card but am getting a core dump.
>> USRYIELD 114. PHOTON -94. rPbConv rTaEnDsW PhotAD
>> USRYIELD 180. 0.0 36. .05 0.0&
>> I have not used USRYIELD before and am not sure it is the right estimator for this purpose.
>> I left WHAT(12) (Material of the target for cross section or LET calculations) blank.
>> Thank you,
>> Mina

Received on Tue Nov 15 2011 - 19:04:15 CET

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