In order to test the V0 prototype response a test with SPARC electron beam is planned for February 2010. The beam will propagate in vacuum until an Al flange (0.4mm thickness): after that the propagation is in Air, first it goes through a Toroidal Charge Monitoring TCM (distant ~6cm from the Al flange) and then it reaches the scintillating fibers (distant ~12cm from the Al flange).

A Geant4 simulation was performed to understand which would be the difference in charge between the one measured by the TCM and the one arriving to the detector posizion. Difference due to the propagation in Air (electron multiple scattering, ionization …) and the presence of non scintillating cladding material before the core (where the photons are produced) of the scintillating fifers.

Numerically we have

• Δq/q = 5.3 ± 0.7 ‰ variation in charge between the one read by the TCM and the one generated before the Al flange position.

• Δq/q = 3.3 ± 0.6 ‰ variation in charge between the one impacting the core of the scintillating fibers and Al flange position. Unordered List Item

As expected the charge variation decrease at ~12cm with respect the one measured at ~6cm because of electron energy loss and large angle scattering.

Another useful information is about the electron beam distribution: the beam has a Gaussian shape (some multiple scattering tails can be observed) with sigma

• σ = 0.2937 ± 0.0024mm sigma at ~6cm, where the TCM is placed;

• σ = 0.5842 ± 0.0048mm sigma at ~12cm, where the detector is placed.

Details about the simulation, plots and results are discussed in a short pdf file:

delta_q_sparc.pdf