ProtoDUNE-SP, sized to hold a total of 770 metric tons of LAr, will be the largest monolithic single-phase LArTPC volume yet built. It is the single-phase far detector prototype that members of the DUNE collaboration will construct and operate at the CERN Neutrino Platform starting in 2017.
ProtoDUNE-SP will be used to validate and benchmark the Far Detector single-phase engineering designs and processes, and infrastructure requirements, and serve as a critical engineering milestone prior to the construction and operation of the ﬁrst full 10-kt DUNE detector module.
The prototype will also undergo a charged-particle beam test at CERN.
“The primary goal of the ProtoDUNE-SP test beam program is to perform the measurements needed to control and understand the systematic uncertainties that will be present in the DUNE oscillation measurements,” said Flavio Cavanna, one of the ProtoDUNE-SP coordinators. “We will use pions and protons from a few hundred MeV to a few GeV, the same range that we expect for the DUNE far detector.”
The test beam run will be used primarily to study hadronic interaction mechanisms, secondary particle production and, at higher energies, shower reconstruction and energy calibration. Electrons will be used to benchmark and tune electron/photon separation algorithms, to study electromagnetic cascade processes and to calibrate electromagnetic showers at higher energies. Samples of Michel electrons from decaying muons will be used for energy calibrations and for charge-sign determination. Charged kaons, even if collected at low statistics, will be used to characterize kaon PID efficiency for proton decay sensitivity.
“Comparably detailed information cannot be gained in situ with the future DUNE detector at its underground location,” Cavanna said.
This several-week-long run is expected to take place just before the long shutdown at CERN starting in late 2018. During the shutdown, ProtoDUNE-SP will operate with cosmic rays.
“We’re considering an additional test beam run after the CERN accelerator starts up again in 2021,” said Cavanna. “This will provide a more complete calibration of the detector.”
ProtoDUNE-SP will be constructed at CERN using both DOE and international funding. It is about 20 times larger than the 35-ton prototype, but still 20 times smaller than a DUNE far detector module. Given the scale of the effort required to build and operate this prototype, it is considered a significant experiment in its own right.
— Anne Heavey