Testing of cryogenic photomultiplier tubes for the MicroBooNE experiment

Abstract

The MicroBooNE detector, to be located on axis in the Booster Neutrino Beamline (BNB) at the Fermi National Accelerator Laboratory (Fermilab), consists of two main components: a large liquid argon time projection chamber (LArTPC), and a light collection system. Thirty 8-inch diameter Hamamatsu R5912-02mod cryogenic photomultiplier tubes (PMTs) will detect the scintillation light generated in the liquid argon (LAr). This article first describes the MicroBooNE PMT performance test procedures, including how the light collection system functions in the detector, and the design of the PMT base. The design of the cryogenic test stand is then discussed, and finally the results of the cryogenic tests are reported.

Cryogenic R5912-20Mod photomultiplier tube characterization for the ProtoDUNE dual phase detector

“…As a result, tests are taken always at least 3 days after immersion. A very similar behavior is reported in [9]. A variation of the gain is expected when the PMT output current increases, either, due to high gain, to high light intensity or to high rate of the light (or a combination of them).…”

“…This PMT was successfully operated in the WA105 3×1×1 m 3 detector [8]. Also, similar PMTs were used in other LAr experiments like MicroBooNE [9], MiniCLEAN [10], ArDM [11] and ICARUS T600 [12].…”

Comparison between large area photo-multiplier tubes at cryogenic temperature for neutrino and rare event physics experiments

“…) PMTs are directly immersed in liquid Ar or Xe at cryogenic temperature. In view of future applications, three new large area PMTs, Hamamatsu R5912 Mod and R5912-02 Mod (see also [4][5][6]) and ETL 9357 KFLB, were characterized both at room (Sections 2 and 3) and at cryogenic temperature (Section 4). Collected data are compared with those obtained with 54 ETL 9357 FLA PMTs successfully employed in the ICARUS experiment [7,8].…”

The MicroBooNE light collection system

“…It is known that the gain of a PMT drops in a cryogenic environment, therefore a high gain PMT, such as R5912-02mod, can compensate for the gain drop by increasing the high voltage value. We tested all PMTs used for the experiment, and confirmed this gain drop can be recovered easily by increasing the high voltage by 200 V. More details of the PMT base structure and the PMT test results can be found in elsewhere [6]. Figure 3 shows a schematic drawing of the PMT mount.…”