A study is ongoing to try to understand the specific differences between FLUKA and Geant4 simulations. Comparison to data are pursued wherever possible, although data is difficult to produce and not very abundant at present.

It is important in such a study to be very specific about what physics models are involved in simulations. Typically this is stated through version numbers of either Geant4 or FLUKA. Formally this is not enough by itself for Geant4 since the physics list is modular and can be changed even within one compiled versions. For now a simple specification of the versions used in this page are included, to be updated and made more specific later:

• Geant4.9.3: without muon-nuclear turned on
• Geant4.9.3+: this is a version of Geant4 which is Geant4.9.3 with the “shielding” physics list (implemented in v4.9.4) and a new muon-nuclear interaction (to be implemented in v4.9.5) have been backported
• FLUKA 2011.2.5

Several of the more important plots can be viewed below in separate sections and additional plots are available here.

For the scintillator material composed of C₉H₁₂ which has density 0.887 g/cm³ which is similar to the Borexino scintillator, several plots have been produced.

Several of the more important plots can be viewed below and additional plots are available here.

for 280 GeV muons the time to capture on hydrogen is plotted below

for 280 GeV muons the radius at which the hydrogen capture takes place is plotted below, the distance is computed from the axis of the cylinder

for 280 GeV muons the multiplicity within each event of hydrogen captures is plotted below

As muons propagate through a cylindrical volume they begin creating neutrons and eventually the flux through the cylindrical area comes to constant. This means in the first small percentage of the cylinder the flux is increasing and after that one can reliably extract the flux. Below we plot the integrated flux (over the whole 10m sensitive cylinder) as a function of energy.

Several of the more important plots can be viewed below and additional plots are available here

for 280 GeV muons and Borexino scintillator we plot the integrated flux as a function of energy

for 100 GeV muons and lead we plot the integrated flux as a function of energy