Problem 2610 - wrong electron spectrum for 138La
Summary: wrong electron spectrum for 138La
Status: ASSIGNED
Alias: None
Product: Geant4
Classification: Unclassified
Component: processes/hadronic/models/radioactive_decay (show other problems)
Version: 11.2
Hardware: All All
: P4 minor
Assignee: dennis.herbert.wright
URL:
Depends on:
Blocks:
 
Reported: 2024-04-25 18:14 CEST by Zoltan
Modified: 2024-04-26 18:51 CEST (History)
2 users (show)

See Also:

Attachments
electron energy spectrum from the decay of 138La for version 11.2.1 (upper) and 10.4.0 (lower) (22.59 KB, image/png)
2024-04-25 18:14 CEST, Zoltan 		Details
Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this problem.
Description Zoltan 2024-04-25 18:14:33 CEST 
Created attachment 866 [details]
electron energy spectrum from the decay of 138La for version 11.2.1 (upper) and 10.4.0 (lower)

Dear Developers,

we are simulating the intrinsic background of LaBr(Ce) detectors with the newest version of Geant (11.2.1). We have observed that the simulated and the experimental spectra significantly differ around 700-1000 keV.

In principle, there must be an extended peaklike structure coming from the decay of 138La in the detector material. It comes from the gamma-ray of 789 keV added to the electron spectrum with an endpoint of around 260 keV.

With the newest version the cutoff of the peak was around 910-920 keV instead of 1050 keV. However, we found a literature paper in which version 10.4.0 was used to simulate the intrinsic background of LaBr(Ce) detectors, and the simulated spectra extended to the correct value of 1050 keV.

Therefore, we have plotted the electron spectra with the two versions. Version 11.2.1 gives a spectrum with a wrong cutoff of around 130 keV, however, version 10.4.0 gives the correct cutoff at around 260 keV.

Best regards,
Zoltan