52Cr deexcitation scheme

Physics Processes, Models and Cross Sections
1

Hello everybody.
52Cr is a stable isotope of Cr (Z=24 and A=52). If neutrons undergo inelastic interaction with 52Cr, then it will be exited, and as a result, it will be deexcited to the ground state (Same situation for 12C).
Please look at the screenshot:

1106×856 151 KB

I know it is possible to simulate neutrons and a 52Cr target with a high energy resolution gamma detector to detect those gamma-rays, but as the probability of neutron inelastic interaction with 52Cr is not so high, therefore the efficiency of the simulation will be too low and needs a huge number of particles to achieve a suitable precision. I decided to simulate the decay scheme of 52Cr (in the screenshot) directly. I mean, I am interested in simulating those gamma-rays (with the exact cascades and energies) without using neutrons. In other words, those gamma-rays will be the primary particles. I tried to simulate this thing using the gps source definition like this:
/gps/particle ion
/gps/ion 24 52 0 0
/run/beamOn 10000
But I think it is not correct, as I could not see any gamma-rays in the defined radiation detector. I think the problem can be due to the fact that 52Cr is a stable isotope, and my gps source definition (above) is related to the natural spontaneous isotopes. Any help please?

2

Hi,

If I am not mistaken, this lines implement the de-excitation of a 10MeV excited 52Cr nucleus per event


/gps/particle ion
/gps/ion 24 52 0 10000

/gps/number 1

/gps/pos/type Plane
/gps/pos/shape Circle
/gps/pos/radius 0.5 mm
/gps/pos/centre  0 0 0  mm
/gps/ang/type iso

/run/beamOn 10000

However, biasing of the physics may be the way to go,

https://geant4-userdoc.web.cern.ch/UsersGuides/ForApplicationDeveloper/html/Fundamentals/biasing.html#physics-based-biasing

Best,
Alvaro.

1 Like
3

Here, an example of macro for examples/extended/radioactivedecay/rdecay01

52Cr.mac.txt (355 Bytes)
52Cr.out.txt (8.5 KB)

52Cr
52Cr698×475 22.2 KB

2 Likes
4

Thank you for your reply,
Is it possible to use /rdecay01/fullChain true in gps source definition? I tried but I got this error message:
**** COMMAND NOT FOUND </rdecay01/fullChain true> ****

**** Batch is interrupted!! ****

-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : UIMAN0123
issued by : G4UImanager::ApplyCommand
Command aborted (100)
Error code : 100
** This is just a warning message. **
-------- WWWW -------- G4Exception-END --------- WWWW -------

5

This command is specific to rdecay01 example.

You do not need it: full decay chain is the default in G4RadioactiveDecay. Make sur that this process is registered in your physics list.

I would recommend to run few events with verbosity :
/tracking/verbose 2
/run/beamOn 1
/tracking/verbose 0

make sur that you have in your main :
//use G4SteppingVerboseWithUnits
G4int precision = 4;
G4SteppingVerbose::UseBestUnit(precision);