A. Ariga for the DsTau TB team DsTau Test Beam 2017

Set up

Summary All planned program was successfully done Refined detector structure Intensity driven stage control Photographic development in Bern currently ongoing. Thank you!

Akitaka Ariga, University of Bern DsTau beam test 2017 Physics goal: Study tau neutrino production by proton beam  ultimately, to test lepton universality Precision measurement of Ds differential production cross-section (Dstnt) Successful beam test in 2016 for the proof of principle 1/40 scale of DsTau full design. The analysis is ongoing. This year, Test an updated detector design, especially film design to improve angular resolution Test lower intensity to fully reconstruct the kinematical information (Momentum measurement in ECC) To improve exposure sequence (Intensity driven synchronization between beam intensity and target mover) Akitaka Ariga, University of Bern

Module structure for Ds → τ → X measurement ECC for momentum measurement (26 emulsion films interleaved with 1 mm thick lead plates) 5~10 units (total 50~100 emulsion films) X 12.5 cm 1 module (5.3 mm) Proton beam (Z)  105 protons/cm2 (uniform irradiation) Y 10 cm Ds t X D+ Z 5.9~8.6 cm (5~10 units + ECC) Target mover Module Silicon detector Detector structure is similar with the previous. Film structure was changed (Emulsion and plastic base thickness). Akitaka Ariga, University of Bern

Intensity driven stage control This year, control speed depending on the beam intensity. Flat top was not flat! Last year, the target mover moved with a constant speed during FT, which made no uniformity of proton density. beta ray intensity stage speed (mm/s) Resulting counts per position Akitaka Ariga, University of Bern

Akitaka Ariga, University of Bern Requests for beam Beam: 400 GeV protons. Intensity: 104-105/spill. Profile: broader is better (e.g. 2 cm x 2 cm). Beam time structure to be flat as much as possible to achieve uniform irradiation. Plans 19th Friday 8 AM, beam time start Beam tuning by Adrian and Bastien from 10 AM. Hope to start data taking in the evening. Beam time until 24th 8 Am. Akitaka Ariga, University of Bern

Intensity driven stage control Flat top was not flat! Last year, the target mover moved with a constant speed during FT, which made no uniformity of proton position distribution This year, control speed depending on the beam intensity. beta ray intensity Flat top stage speed stage speed (mm/s) beam t Resulting counts per position Akitaka Ariga, University of Bern