Date: Sun, 21 Oct 2018 10:04:32 +0800 (GMT+08:00)
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.
① I set the first quantity polar angle θ (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 θ,indeed, I know this distribution is isotropic, but it corresponds to the solid angle Ω not the polar angle θ(i.e.,dΩ=2πsinθdθ). Suppose dN/dΩ=A(some constant),thus,dN/dθ=2Aπsinθ,so at the angle near 0° , we should get a minimal value, and get a maximal value near 90° (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/dΩ? I'm very confused about this, if it is the result of dN/dΩ, then how to obtain dN/dθ (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/dθ only by multiplying the USRYIELD output results by the factor 2πsinθ (shown in figure2, indeed showing a minimal near 0°), 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 Ω.
② 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 α 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
__________________________________________________________________________
You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?id=acc_info
- application/octet-stream attachment: usryield.inp
- application/octet-stream attachment: gem_25_sum.lis
- application/octet-stream attachment: gem_32_sum.lis
(image/jpeg attachment: figure1.jpg)
(image/jpeg attachment: figure2.jpg)