Performance of new 8-inch photomultiplier tube used for the Tibet muon-detector array

Abstract

A new hybrid experiment has been constructed to measure the chemical composition of cosmic rays around the "knee" in the wide energy range by the Tibet ASγ collaboration at Tibet, China, since 2014. They consist of a high-energy air-shower-core array (YAC-II), a high-density air-shower array (Tibet-III) and a large underground water-Cherenkov muon-detector array (MD). In order to obtain the primary proton, helium and iron spectra and their "knee" positions in the energy range lower than 10 16 eV, each of PMTs equipped to the MD cell is required to measure the number of photons capable of covering a wide dynamic range of 100 -10 6 photoelectrons (PEs) according to Monte Carlo simulations. In this paper, we firstly compare the characteristic features between R5912-PMT made by Japan Hamamatsu and CR365-PMT made by Beijing Hamamatsu. This is the first comparison between R5912-PMT and CR365-PMT. If there exists no serious difference, we will then add two 8-inch-in-diameter PMTs to meet our requirements in each MD cell, which are responsible for the range of 100 -10000 PEs * Corresponded author Email: yingzhang@ihep.ac.cn and 2000 -1000000 PEs, respectively. That is, MD cell is expected to be able to measure the number of muons over 6 orders of magnitude.

Mass Testing and Characterization of 20-inch PMTs for JUNO

“…This ratio is expected to be less than 15% of the initial pulse charge. There are already distinct studies about after-pulses [22,28,48,91,92]. This study only measured a sample of several ∼ 100s PMTs using the scanning station as shown in [93].…”

“…6. Meanwhile, it is valuable to stress that several other PMT characterization campaigns were performed in the past; we mention those of the IceCube [34], MiniBooNE [35], IMB [36], Borexino [37,38], Daya Bay [39], Chooz [40], SNO [41], Double Chooz [42,43], DAMA [44], Auger [45,46], ANNIE [47], YBJ [48], LHAASO [49,50], Hyper-Kamiokande [51,52], and KM3Net [53,54] experiments. For completeness, it should be noted here that the 3-inch PMTs used for JUNO are investigated as well in a separate campaign [55,56].…”

Dynamic range extension of the Tibet underground muon detectors for measurements up to the knee energy region with 3-inch photomultipliers

“…Clearly, such a dynamic range is not sufficient to measure CRs at the knee energies. In previous work, we considered adding two 8-inch PMTs (Beijing Hamamatsu CR365) in each MD cell for measurements extending towards the knee region [12]. As shown in figure 1, the MC simulation indicates that the air showers induced by the knee-region CRs can give rise to peak signals up to ∼10 6 PEs when they are detected by an 8-inch PMT in an MD pool cell.…”

“…As the CR365 has been investigated in ref. [12], we here focus on whether the dynamic range of an MD cell can be extended for measurements up to the knee energies with the XP72B22.…”

Test results of new CR365-PMTs for the Tibet muon-detector array

“…We have compared the characteristic features between R5912-PMT made by Japan Hamamatsu and CR365-PMT made by Beijing Hamamatsu and found that CR365-PMT fulfill our requirements. Detail comparison is described in the paper [9]. Since it is the first time for Beijing Hamamatsu to produce this type of 8-inch-in-diameter PMTs largely, we have to test the performance of PMTs seriousely whether they can satisfy our request; we can also provide valuable feedback to the company.…”