Re: Gamma rays

Dear Roser,

To add to Alberto's instructions for defining 60Co (or any other radioactive source), I add the following:

When I looked into this few months ago with the help of Sebastien and Joachim, I found out having a radioactive source
requires the use of either a RADDECAY and a DCYSCORE card or a RADDECAY, DCYTIMES, and DCYSCORE cards.
Without these, no decay particles are tracked.

- If one uses 1 for WHAT(1) for RADDECAY card (Active), then radioactive decays are activated for requested cooling
times and one should use DCYTIMES with requested times. This means you need to associate whatever distribution you are
looking at via your choice of estimators, with a given decay time defined in the DCYTIMES card, using a DCYSCORE card.

EX:
RADDECAY 1. 3.
DCYTIMES 30. 3600. 86400.
RESNUCLE 3. -21. 74. 49. rTa27 1.RNTgt
DCYSCORE 1. RNTgt RESNUCLE

In the above, I am defining three decay times 30 sec, 1 hour, and 1 day. Using the RESNUCLE & DCYSCORE cards, I am
looking at the activity in the rTa27 region, t=30 seconds.

- If one uses 2 for WHAT(1) for RADDECAY card (Semi-Analogue), then radioactive decays are activated in semi-analogue
mode and one needs only a DCYSCORE time using -1 for WHAT(1) to use the Semi-Analogue mode.

EX:
RADDECAY 2. 3.
DCYSCORE -1. RNTgt RESNUCLE

This is the extent of my understanding. I don't believe you can set the activity level of the source at the start of
your run. I also do not have a good grasp of the Semi-Analogue mode.

It would be nice if a section was added to the manual, explaining all the cards that NEED be used in order for setting a
radioisotope (radioactive) source as the beam.

Best wishes,
Mina

On 12-07-08 08:05 AM, Alberto Fasso' wrote:

> Dear Roser,
> gamma rays are photons.
> To simulate a source of Gamma rays of 1.3 MeV, use a BEAM card with
> WHAT(1) = 0.0013 and SDUM = PHOTON.
> If the source is isotropic, set WHAT(3) = 7000.

> For 60Co, this is an approximation, because 60Co doesn't emit one gamma of
> 1.3 MeV, but two gammas, one of 1.173 MeV, and one of 1.332 MeV.
> If you want to simulate accurately an isotropic 60Co source, use a BEAM card
> with WHAT(3) = 7000., all other WHATs = 0., and SDUM = ISOTOPE, and a card HI-PROPE
> with WHAT(1) = 27. and WHAT(2) = 60.
>
> Alberto

>> Dear FLUKA users and experts,
>> I would like to simulate the effects of gamma rays.
>> -I need to simulate a source of Gamma rays of 1.3 MeV. (For exemple a 60Co source)
>> -I also need to define the number of the incident photons.
>> -This gamma rays interact with a 1.0 mm Si slab.
>> My problem is that I didn't find how to simulate gamma rays. May you please
>> help me? Thanks.
>> Roser
Received on Tue Jul 10 2012 - 00:14:07 CEST