Re: [fluka-discuss]: γ ray count problem using USRBDX

From: Mikhail Polkovnikov <pmk_at_ihep.ru>
Date: Fri, 6 May 2016 13:22:48 +0300

On 06.05.2016 12:32, YANG Tao wrote:
> Dear Mikhail!
>
> Thanks a lot for your reply! It may be the problem of the FLAIR
> software in my computer, I got the correct result in the server. But I
> have some other problems as follows:
>
> 1. What's the difference of BEAMPART and PHOTON in my input file? The
> BEAMPART is indeed photon in my input, so the two settings are both
> correct, do you think so?
>
> 2. You set the fluence scoring instead of current scoring in the
> USRBDX card, Why do you set as this form, in my opinion, the COUNT of
> the photon number should be one-way current scoring. Besides, the
> output photon number is not the same for the two different setting of
> the USRBDX card. However, in formula calculations the results I/I0
> should be 2.1E-4 and your input file gets the correct result(about
> 2.0E-4 _at_primary number is 1000), and the one-way current setting in
> USRBDX gets a much bigger result (~1.0E-3).
> Could you solve the puzzles for me?
>
> All the best!
>
> Tao Yang
>
>
> -----原始邮件-----
> *发件人:* "Mikhail Polkovnikov <Михаил Полковников>" <pmk_at_ihep.ru>
> *发送时间:* 2016年5月6日 星期五
> *收件人:* "YANG Tao" <yangt_at_ihep.ac.cn>, fluka-discuss_at_fluka.org
> *抄送:*
> *主题:* Re: [fluka-discuss]: γ ray count problem using USRBDX
>
> 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
>
>
> --
>
> 杨涛
> 中科院高能所东莞分部(东莞中子科学中心)加速器技术部
> 地址:东莞市大朗镇中子源路1号中国散裂中子源A2栋606室
> E-mail:yangt_at_ihep.ac.cn <mailto:yangt_at_ihep.ac.cn>
> 电话:0769-38944239
> 邮编:523803
>

Dear Tao Yang,

1. In your case BEAMPART are only primary photons from the source,
PHOTON are all photons (primary + scattered). That is why the result
with part=PHOTON in your USRBDX is bigger.
2. You can set one-way current scoring and the result will be basically
the same for BEAMPART photons.

Best regards,
Mikhail


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Received on Fri May 06 2016 - 14:54:38 CEST

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