Speaker
Description
Particle identification is one of the crucial and difficult task for the high energy physics experiments, like the future FCC-ee, CEPC, SCTF. The ionization of matter by charged particles is the primary mechanism used for particle identification (dE/dx), but the large uncertainties in the total energy deposition represent a limit to the particle separation capabilities. The cluster counting technique (dN/dx) takes advantage from the primary ionization \textit{Poissonian} nature and offers a more statistically significant way to infer the mass information. To investigate the potential of the cluster counting techniques on physics events a simulation of the ionization clusters generation is needed. To this purpose, we developed an algorithm which can use the energy deposit information provided by Geant4 software tool to reproduce, in a fast and convenient way, the clusters number distribution and the cluster size distribution. The results obtained confirm that the cluster counting technique allows to reach a resolution 2 times better than the traditional dE/dx method. To validate the simulations results, we performed a first test beam at CERN with a pack of drift tubes, by using a muon beam of 165 GeV, by collecting data with two gas mixtures, which are 90$\%$ He and 10$\%$ $ iC_{4}H_{10}$ and 80$\%$ He and 20$\%$ $ iC_{4}H_{10}$, at different gas gain and angle configurations.
The final goal of the test beam will be the possibility to study:
- the counting efficiency as a function of gas mixture, gain, geometrical configuration (cell size, sense wires size), arrival time of the first cluster
- the cluster density as a function of ionization length and angle
- the cluster dimension as a function of gain and cell size
- the definition of the optimal condition for the next test (next spring) whose goal will be the measurement of the relativistic rise of dN/dx and dE/dx.
