# USRYIELD scoring angle intervals of particles coming opposite to beam direction

Hello to everyone!

I am a bit confused about USRYIELD scoring. I want to calculate plain double differential yield with x1 as Ekin GeV and x2 as Polar $\theta$ lab deg. I have this setup (see pic 1):

So, at first, beam direction is perpendicular to the edge (aligned with normal) and I am trying to score particles coming from region 2 to region 1 at different angle intervals (indicated as ? sign on the picture). Am I right, that in the USRYIELD I need to define angle intervals marked as stars? So, between beam direction and particle? And the second setup (see pic 2):

So, this time I want to score particles coming from region 2 to region 1 at different angles (indicated as ? sign on the picture) as well, I am intrested in angles between normal and particles coming from region 2. Am I right, that this time I need to define angle intervals marked as stars on the picture 2? As it stated in the manual, and how exactly can I fix the direction to be as it was on the picture before? To compare spectra of particles with the first setup? Iâ€™ve tried to define USRYIELD with BEAMDEF with cosine z equal to 1, but seems this doesnâ€™t work, also, Iâ€™ve managed to direct beam at different angles using BEAMAXES, maybe this is the reason. As a summary: I want to compare spectra of particles in the same angle intervals regarding to normal in these different setups with different initial beam directions.

Best regards,
Ivan

Dear @Ivan,

What you describe about the angles is correct.
If you are interested in defining your 0 deg as the normal of your boundary ( pointing from 2 to 1), then you should add an extra USRYIELD card with BEAMDEF = -1.
This should define the angles that you described as â€ś?â€ť

Also, I see that you were able to modify the angle of the primary particles using BEAMAXES. Just in case, maybe you know that It can be done with the BEAMPOS card as well.

Let me know if you need more details.
I hope it is useful for you.

Best,

2 Likes

If I understood right, I can set BEAMDEF = -1 and this will be normal direction all the time doesnâ€™t matter what was the initial beam direction? Even if I did this via BEAMAXES? So, if I will change beam direction, for USRYIELD scoring it will be -1 all the time? It is solves my problem if it is so.

Regards,
Ivan

Dear @Ivan,

Exactly, BEAMAXES does not change anything in the USRYIELD scoring because the BEAMDEF=-1 depends on the geometry and not the beam direction.

Just a few comments, because I was maybe assuming many things from your problem in the previous post.

1. Of course, as you well understood, when I said BEAMDEF=1 I meant the cosz= -1 for BEAMDEF. As you can see, it helps you for your particular problem considering that the normal to your edge is pointing to -z
2. I said that you could use also BEAMPOS for your problem, but I donâ€™t know actually what you need for you source of primaries. In case that your beam has no size, you are ok, but if thatâ€™s not the case, check these slides to have more detail of the differences (pages 15-17)
1. Another suggestion for you is to use another scoring card (USRBDX). Using this scoring your reference direction will be always the normal to your edge. See more here:

In case that you need more help,
just let me know

Best,