On 06.05.2016 04:21, YANG Tao wrote:
> Hello, everyone!
>
> I simulate the lead shielding effect for γ ray recently, but I got a
> strange result. Beam position is at (0,0,0) and the beam direction is
> in z-direction. The gamma rays were directed towards a simple
> cuboid lead block with 10.5 cm in thickness and 200cm*200cm in length
> and width. USRBDX score card has been used to obtain the transmission
> values, I/I0, where I0 and I**are the incident and attenuated photon
> intensities. Theoretically, I0 is 1 photon/primary since the incident
> photon will all penetrate the front surface of the lead block,
> however, the result (31BIN, "rushe") always give *ZERO* result, it's
> confusing, where did the photons go? Additionly, the exit photon
> (32BIN, "chushe") also give a wrong results compared to other literature.
> These problems have confused me for several days, so any help will be
> appreciated much!!!
> Thank You!
>
> Tao Yang
>
> CAS
>
Dear Tao Yang,
If you are interested only in attenuation of primary photons, you can
try these two USRBDX's:
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....
USRBDX 109. BEAMPART 21. valeft qiankuai 1.in
USRBDX 1.0E-3 8.0E-4 1. 1. &
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....
USRBDX 109. BEAMPART 21. qiankuai varigh 1.out
USRBDX 1.0E-3 8.0E-4 1. 1. &
In - input fluence before lead block
out - output fluence after lead block
The value (out / in) is close to the formula calculations ( mu = 0.07102
cm^2/g, density = 11,35 g/cm^3)
Best regards,
Mikhail
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Received on Fri May 06 2016 - 11:06:05 CEST