Lifetime of MCP-PMTs and other performance features

Abstract

A: The PANDA experiment at FAIR will use DIRC detectors for the separation of hadrons. The compactness of the PANDA detector requires the image planes of these detectors to be placed inside the magnetic field of the solenoid. Due to this and other boundary conditions MCP-PMTs were identified as the only suitable photon sensors. Until recently the major obstacle for an application of MCP-PMTs in high rate experiments like PANDA were serious aging problems which led to damage at the photo-cathode and a fast declining quantum efficiency as the integrated anode charge (IAC) increased. With new countermeasures against the aging, in particular due to the application of an atomic layer deposition (ALD) technique to coat the MCP pores, the lifetime of MCP-PMTs has meanwhile increased by a factor >50 which is fully sufficient for PANDA. The recent results of our long-term lifetime measurements are discussed. New 2-inch MCP-PMT prototypes from Hamamatsu show an encouraging behavior. However, the currently best performing MCP-PMT is a 2-inch PHOTONIS tube with two ALD-layers which reaches an IAC of >16 C/cm 2 without any visible sign of aging. In the second part of these proceedings a new data acquisition system of the PADIWA/TRB type is presented which allows a quasi-parallel measurement of many MCP-PMT performance parameters. Especially unwanted effects like dark-count rate, crosstalk, ion afterpulsing, and recoil electrons can be studied in more detail than ever before. Exemplary results for these parameters are shown. The discussed DAQ system will be used for the comprehensive data quality checks of the MCP-PMTs being built into the DIRCs. K: Photon detectors for UV, visible and IR photons (vacuum), Microchannel-plate photomultipliers, Cherenkov detectors.

High-detection efficiency MCP-PMTs with single photon counting capability for LIDAR applications

“…For space grade detectors being under development we expect to improve the intrinsic lifetime of S-20 Hi-QE MCP-PMTs by a factor of 2-3. This long lifetime MCP technology is being tested on the Planacon™, another MCP-PMT device from Photonis, though the conditions of use are different the results presented in [6] are very promising.…”

“…A MCP-PMT is a vacuum device consisting of a photocathode, absorbing the light and emitting photoelectrons, typically two MCPs, multiplying the electrons from the photocathode by a factor of about 10 5 -10 6 and an anode that can be single or segmented, to collect the output bunches of electrons. The time resolution of these devices is in the ns or even sub-ns range with a rise time and time transfer spread being below 200 ps and 40 ps (σ), respectively.…”

Fast and efficient detection of 511 keV photons using Cherenkov light in PbF2 crystal, coupled to a MCP-PMT and SAMPIC digitization module

“…This happens due to the so-called charge sharing effect, when the electron shower induces signals simultaneously on two anode electrodes, see e.g. [56][57][58]. We observe that charge sharing happens at the distance of 1-2 mm from the pad edge.…”

Air-Transfer Production Method for Large-Area Picosecond Photodetectors

“…The small feature size, concomitant good resolutions, and high gain are intrinsic rather than highly tuned [9]. The ALD-based functionalization of the glass capillary substrates [34,35] eliminates the shortened tube lifetime due to ion feedback [1,51].…”