(1) Management and conduct of Phase-α.
As the Phase-α working group (WG) leader, I assumed responsibility for guiding the team through the project's various stages. Initially comprising a few core members, the WG expanded to include over 30 international researchers and students from around the world by the time of the experiment. I organised regular WG meetings and collaborated with members to determine the detector setup and experimental run plans. Managing several subgroups for detector developments, I provided leadership and direction to ensure the project's success. The entire WG's activities received high praise from the collaboration.
The Phase-α experiment took place over two weeks in February and March 2023 at J-PARC, marking the first commissioning opportunity for the TS. During the experiment, I oversaw data-taking and managed shift personnel, ensuring smooth operations and data quality.
(2) Range Counter development for Phase-α
The Range Counter (RC) played a crucial role in Phase-α by measuring the momentum spectrum of the negative muon beam transported by the TS. At the onset of the project in June 2022, I conducted an experiment to evaluate the first prototype of the RC using a slow negative muon beam at the Materials and Life Science Experimental Facility of J-PARC [3]. This experiment confirmed the RC's principle idea of counting negative muons and finalised its design. During Phase-α, the actual RC performed successfully, contributing to the first measurement of negative muons and their momentum spectrum.
Following the completion of the Phase-α experiment, another small experiment was conducted in November 2023 at PSI to assess the performance of the RC used in Phase-α.
(3) Conduct of a test-beam campaign at Paul Scherrer Institut in Switzerland for COMET including the BB development
The test-beam experiment conducted in November 2023 at PSI incorporated sub-experiments aimed at evaluating three detectors crucial to COMET: the BB, RC, and a hodoscope detector. Refer to (2) for details of the RC part.
A simple BB prototype was constructed using tungsten plates and subjected to testing with low-momentum electron, muon, and pion beams at PSI. The primary objectives were to assess its stopping power against various momenta of the primary beams of interest in COMET and to observe the secondary particles generated from the halted primary beams. While the expected stopping power was achieved, discrepancies emerged between the measured number and phase space of the generated secondary particles and the simulation estimates, deviating by up to a few tens of percent or more, as initially suspected. Consequently, modifications will be made to the software.
Additionally, the hodoscope detector, serving as the final prototype of the COMET Cylindrical Trigger Hodoscope, underwent successful evaluation.
[3]
https://mlfinfo.jp/en/proposals/2022A.html(s’ouvre dans une nouvelle fenêtre)
