Speaker
Stefano Miscetti
(LNF)
Description
he Mu2e experiment at FNAL aims to measure the conversion of a
$\mu^-$ to an electron, resulting in a mono-chromatic $e^-$ signal
with an energy of $\sim$ 105 MeV, and reach a single event sensitivity
of ~ $2.5 \times 10^{-17}$ in three years of running.
The calorimeter has to perform $\mu$/e particle identification,
support/improve the tracking pattern recognition and provide
a tracking independent software trigger for the experiment.
It should be able to keep functionality in an
environment where the n, p and $\gamma$ background, from
muon capture processes and beam flash events, deliver a
maximum dose of ~ 120 Gy/year. It should also work
in 1 T axial magnetic field and a $10^{-4}$ torr vacuum.
These requirements ask for a calorimeter with large acceptance
for signal events and a reasonable energy O(5\%) and time
O($<$ 500 ps) resolution. Due to the sudden LYSO cost increase,
the baseline calorimeter version is now composed of two disks
of $\sim$ 900 BaF$_2$ crystals. This choice matches the requirement
of fast, high resolution and radiation hardness crystals. Each cell
is read out by two APDs whose signals are amplified, shaped and
readout through 200 msps waveform digitizers.
We show the calorimeter design, the results obtained at 100 MeV
with a small size LYSO prototype, to test a first version of
calorimeter system integration, and the $R\&D$ and simulation
carried out to prove the validity of the new baseline.
Primary author
Stefano Miscetti
(LNF)
