Evaluation of the absolute single-photon detection efficiency of HRPPD

TL;DR

The paper addresses the need for an absolute measurement of photon detection efficiency (PDE) for HRPPDs, evaluating a direct, pulse-counting PDE method at 398.6 nm. It combines Poisson-based modeling with cross-calibration against a NIST-traceable photodiode to relate incident photons to detected pulses, and simultaneously measures QE to obtain the Collection Efficiency (CE). The study reports PDE = $17.13\%$ (stat $0.11\%$, sys $0.30\%$) and QE = $24.37\%$ (stat $0.03\%$, sys $0.32\%$) for a central pixel, yielding CE = $70.3\%$. These results support HRPPDs as viable, high-rate detectors for RICH applications, with the measured CE consistent with MCP open-area expectations and demonstrated uniformity considerations.

Abstract

Pixelated High Rate Picosecond Photon Detectors (HRPPDs) by Incom Inc. are promising photosensors for use in Ring Imaging CHerenkov (RICH) detectors, where a high gain, sub-mm position resolution and sub-100ps timing resolution are required in a single photon mode. Quantum Efficiency (QE) has been measured for the first batch of EIC HRPPDs both by Incom and EIC research groups at Jefferson Lab and Brookhaven Lab, with peak values at $\sim$365 nm typically exceeding 30%. In this study, we present a first direct measurement of Photon Detection Efficiency being equal to (17.1 $\pm$ 0.1 [stat] $\pm$ 0.3 [sys])% at 398.6 nm, for a pixel near the center of HRPPD, in a photoelectron pulse counting mode using a picosecond diode laser. HRPPD QE at the same spot and at the same wavelength was evaluated to be (24.4 $\pm$ 0.1 [stat] $\pm$ 0.3 [sys])%, leading to a Collection Efficiency estimate of (70.3 $\pm$ 1.6)%, which is consistent with the expectations.

Figures (11)

• Figure 1: A schematic view of our PDE measurement setup (left) and a QE measurement setup (right). See text for details.
• Figure 2: Experimental setup.
• Figure 3: HRPPD #27 mounted on a dark box side wall. One can also see the interface board with a pair of plugin MCX adapters.
• Figure 4: A small breadboard with focusing optics mounted on a 3D motion control system inside the dark box. The incoming laser beam, after passing through a beam splitter, was partly focused on the HRPPD photocathode, and partly detected by a reference photodiode. See text for more details.
• Figure 5: Top: PiLas laser wavelength spectrum with a peak value of 398.4 nm and FWHM 1.9 nm as measured by the Ocean Optics spectrometer. Bottom: Newport monochromator wavelength spectrum with a FWHM 3.0 nm and a peak value matching the laser one within 0.1 nm as measured by the spectrometer when using a monochromator wavelength setting of 395.7 nm .