Hi Yang,
1. indeed as note 6 of USRYIELD states the results are always per steradian if an angular scoring is used. To obtain the dN/dtheta you have to calculate
the dtheta/domega when you know that the omega = 2pi(1-cos(theta))
2. As the header of the sum.lis is stating the total response is integrated over x1 (and not x2) you need to multiply with the dx2 to get the similar result
as in the usrbdx 0.2155*2e-3 ~= 4.3e-4
Cheers
Vasilis
________________________________
From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of YANG Tao [yangt_at_ihep.ac.cn]
Sent: Sunday, October 21, 2018 04:04
To: fluka-discuss_at_fluka.org
Subject: [fluka-discuss]: Angular distribution of usryield
Dear fluka users,
Recently I simulate the angular distribution of secondary ions from (n,B) reaction, I using USRYIELD card to obtain this. However, I cannot interpret the results.
$B-!(B I set the first quantity polar angle $B&H(B (polar angle in the c.m.s. frame, relative to the primary beam direction)and second E, I get a similar isotropic distribution over the polar $B&H(B,indeed, I know this distribution is isotropic, but it corresponds to the solid angle $B&8(B not the polar angle $B&H(B(i.e.,d$B&8(B=2$B&P(Bsin$B&H(Bd$B&H(B). Suppose dN/d$B&8(B=A(some constant),thus,dN/d$B&H(B=2A$B&P(Bsin$B&H(B,so at the angle near 0$B!k(B , we should get a minimal value, and get a maximal value near 90$B!k(B (I think it is some counterintuitive). Maybe I misunderstand the output of USRYIELD card, so could anyone interpret the meaning of USRYIELD setting. I read the manual, it states:
"In the case of polar angle quantities (| ie| or | ia| = 14, 15, 17, 18, 24, 25) the differential yield is always referred to solid angle in steradian, although input is specified in radian or degrees."
Does it mean the results shown in figure1 is only dN/d$B&8(B? I'm very confused about this, if it is the result of dN/d$B&8(B, then how to obtain dN/d$B&H(B (the strange thing is that I set the SDUM as polar angle in the usryield input, now that it cannot give the polar angle distribution, why the sdum says it were polar angle)? I try to get dN/d$B&H(B only by multiplying the USRYIELD output results by the factor 2$B&P(Bsin$B&H(B (shown in figure2, indeed showing a minimal near 0$B!k(B), which I think maybe not the correct method since we will loss the statistical meaning if we priori assume the distribution is isotropic in solid angle $B&8(B.
$B-"(B Besides, I find the total response of 32BIN unit of the input file is 0.2155161(gem_32_sum.lis), which I think is the total yield of $B&A(B particle leaving from the layer since it is integrated over two quantities, but the value doesn't match the total response of 25BIN((gem_25_sum.lis)) result which is 4.3065209E-04(gem_25_sum.lis,this value seems to be the true yield basing on the reaction cross section ), do the two responding values have different meaning?
Any help is appreciate!
Best regards!
Yang
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Received on Mon Oct 22 2018 - 12:09:09 CEST