Re: [fluka-discuss]: Effect of neutron beam intensity on activation of Na-23

From: Francesco Cerutti <>
Date: Tue, 25 Aug 2015 19:14:52 +0200


> 1) I am not able to understand why the results in the t35_21_tab.lis and
> t35_22_tab.lis files are in different formats?

because you associated the RESNUCLE scoring on unit 21 to a cooling time
(this way obtaining activity in Bq) while you did not do so for the one on
unit 22 (obtaining isotope production yields, in nuclei per incident
neutron). The second DCYSCORE card should apply to det1 and not to det 2
again (now it supersedes the previous one).

> 2)Assuming the results in t35_21_tab.lis are Bq the result 5.9079E+27
> seems to be too high to be physical as the mass corresponding to this
> activity will be very high (higher than Na-23 cylinder used for
> simulation)

The activity gets this crazy value since it is normalized to the crazy
neutron current of 1e35 n/s you input.

> 3)Is there a limit on p/s value which I can use for simulations?

There is no technical limit, but obviously one should comply with
meaningfulness limits. In this case one wonders where 1e35 n/s can be
found in reality and what is left out of your initial sodium cylinder with
such a flux (FLUKA does not perform material transmutation, i.e. the
assigned materials are assumed not to change during irradiation, which
would not be your case with that pretty intense source)

> 4) What am I doing wrong?

You are normalizing to a meaningless neutron current. And you mistyped a
DCYSCORE card as said before.

Best regards


Francesco Cerutti
CH-1211 Geneva 23
tel. ++41 22 7678962
fax ++41 22 7668854

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Received on Tue Aug 25 2015 - 20:39:25 CEST

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