Development of proton beam irradiation system for the NA65/DsTau experiment

Tau neutrino is the least studied lepton of the Standard Model (SM). The NA65/DsTau experiment targets to investigate $D_s$, the parent particle of the $\nu_\tau$, using the nuclear emulsion-based detector and to decrease the systematic uncertainty of $\nu_\tau$ flux prediction from over 50% to 10% for future beam dump experiments. In the experiment, the emulsion detectors are exposed to the CERN SPS 400 GeV proton beam. To provide optimal conditions for the reconstruction of interactions, the protons are required to be uniformly distributed over the detector's surface with an average density of $10^5~\rm{cm^{-2}}$ and the fluctuation of less than 10%. To address this issue, we developed a new proton irradiation system called the target mover. The new target mover provided irradiation with a proton density of $0.98~\rm{cm^{-2}}$ and the density fluctuation of $2.0\pm 0.3$% in the DsTau 2021 run.Comment: 9 pages, 16 figure

Development of proton beam irradiation system for the NA65/DsTau experiment

Tau neutrino is the least studied lepton of the StandardModel (SM). The NA65/DsTau experiment targets to investigate Ds, the parent particle of the ντ, using the nuclearemulsion-based detector and to decrease the systematic uncertaintyof ντ flux prediction from over 50 % to 10 % for futurebeam dump experiments. In the experiment, the emulsion detectorsare exposed to the CERN SPS 400 GeV proton beam. To provideoptimal conditions for the reconstruction of interactions, theprotons are required to be uniformly distributed over the detector'ssurface with an average density of 10$^{5}$ cm$^{-2}$ and thefluctuation of less than 10%. To address this issue, we developeda new proton irradiation system called the target mover. The newtarget mover provided irradiation with a proton density of1.01 × 10$^{5}$ cm$^{-2}$ and the density fluctuation of1.9 ± 0.3% in the DsTau 2021 run.Tau neutrino is the least studied lepton of the Standard Model (SM). The NA65/DsTau experiment targets to investigate $D_s$, the parent particle of the $\nu_\tau$, using the nuclear emulsion-based detector and to decrease the systematic uncertainty of $\nu_\tau$ flux prediction from over 50% to 10% for future beam dump experiments. In the experiment, the emulsion detectors are exposed to the CERN SPS 400 GeV proton beam. To provide optimal conditions for the reconstruction of interactions, the protons are required to be uniformly distributed over the detector's surface with an average density of $10^5~\rm{cm^{-2}}$ and the fluctuation of less than 10%. To address this issue, we developed a new proton irradiation system called the target mover. The new target mover provided irradiation with a proton density of $0.98~\rm{cm^{-2}}$ and the density fluctuation of $2.0\pm 0.3$% in the DsTau 2021 run