Measurement of the cosmic-induced neutron yield at the Modane underground laboratory

Muon-induced neutrons (µ-ind. n\u27s) are an important background source for Dark Matter searches, e.g. EDELWEISS at Laboratoire Souterrain de Modane (LSM). Within this work, a data set of 313 µ-ind. n\u27s at LSM was collected. Using Geant4 and a calibrated detector response model, the absolute neutron rate is reproduced within 15% and agrees within the uncertainties. This work demonstrates that Geant4 can reliably model the production of µ-ind. n\u27s once a detailed model is implemented

Parallelization of Geant4 Using TOP-C and Marshalgen

Geant4 is a very large, highly accurate toolkit for Monte Carlo simulation of particle-matter interaction. It has been applied to high-energy physics, cosmic ray modeling, radiation shields, radiation therapy, mine detection, and other areas. Geant4 is being used to help design some high energy physics experiments (notably CMS and Atlas) to be run on the future large hadron collider: the largest particle collider in the world. The parallelization, ParGeant4, represents a challenge due to the unique characteristics of Geant4: (i) complex object-oriented design; (ii) intrinsic use of templates and abstract classes to be instantiated later by the end user; (iii) large program with many developers; and (iv) frequent releases. The key issue for parallelization is not just how to parallelize “correctly ” but also how to parallelize “with minimum effort”. In addition, the parallelization should make as few assumptions about the source code as possible, due to the frequent release schedule of Geant4. We use TOP-C (Task Oriented Parallel C/C++) for parallelization and Marshalgen for marshaling/serialization. In some examples on a cluster of 100 nodes yielded a speedup of up to 94.4. The code’s portability, scalability and performance are also discussed.