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The paper reviews recent progress in photodetectors, discussing vacuum-based detectors, semiconductor sensors, and gas-based detectors. The emphasis in this review is on the detection of low light levels, enhanced timing resolution, and spectral range of photon detectors, as well as the development of photosensors for extreme conditions, for operation in cryogenic and high radiation-level environments.

The paper discusses new method for electron/pion and muon/pion separation in the Belle II detector at transverse momenta below 0.7 $\mathrm{GeV}/c$, which is essential for efficient measurements of semi-leptonic decays of $B$ mesons with tau lepton in the final state. The method is based on the analysis of patterns in the electromagnetic calorimeter by using a Convolutional Neural Network (CNN)., Comment: 3 pages, 4 figures. Poster contribution to 11th International Workshop on Ring Imaging Cherenkov Detectors (RICH2022), September 12-16 2022. To be submitted to Nuclear Inst. and Methods in Physics Research, A

The Belle II detector at the SuperKEKB accelerator complex is covering a wide range of exciting physics topics. To achieve the project's research goals, a substantial increase of the data sample to 50~ab$^{-1}$ is needed, and for that, the luminosity has to reach the ambitious goal of $6 \times 10^{35}$ cm$^{-2}$ s$^{-1}$. The progress towards the design luminosity is accompanied by research and development of the accelerator, detector components, operation methods, as well as their upgrades. In the present contribution, we will discuss the status and plans of the project, timescales for upgrades, their motivations, and opportunities, an overview of upgrade options, and finish with an outlook and perspectives.

This paper presents recent progress in the development and mass production of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter, which will be installed in the forward end cap of the Belle II detector. The proximity-focusing A-RICH system is especially designed to identify charged kaons and pions. The refractive index of the installed aerogel Cherenkov radiators is approximately 1.05, and we aim for a separation capability exceeding 4$\sigma $ at momenta up to 4 GeV/$c$. Large-area aerogel tiles (over 18 $\times $ 18 $\times $ 2 cm$^3$) were first fabricated in test productions by pin drying in addition to conventional methods. We proposed to fill the large end-cap region (area 3.5 m$^2$) with 124 water-jet-trimmed fan-shaped dual-layer-focusing aerogel combinations of different refractive indices (1.045 and 1.055). Guided by the test production results, we decided to manufacture aerogels by the conventional method and are currently proceeding with mass production. In an electron beam test undertaken at the DESY, we confirmed that the $K$/$\pi $ separation capability of a prototype A-RICH counter exceeded 4$\sigma $ at 4 GeV/$c$., Comment: To be published in Nucl. Instrum. Methods A,, 5 pages, 5 figures

The paper discusses future experiments at super $B$ factories. It presents the physics motivation and the tools, accelerators and detectors, and reviews the status of the two projects, SuperKEKB/Belle-II in Japan and SuperB in Italy., Comment: Proceedings of CKM2010, the 6th International Workshop on the CKM Unitarity Triangle, University of Warwick, UK, 6-10 September 2010

The mirror system of the HERA-B RICH consists of two spherical and two planar mirrors, composed of altogether 116 mirror segments. Analysis of displacements of the \v{C}erenkov ring center relative to the charged particle track, for given spherical-planar segment pairs, leads to accurate information regarding the orientation of individual mirror segments. The method is described and the effect of applying the required corrections on the \v{C}erenkov angle resolution of the HERA-B RICH is discussed.

The paper reviews recent progress in particle identification methods. A survey of motivations and requirements for particle identification in various experimental environments is followed by the main emphasis, which is on the recent development of Cherenkov counters, from upgrades of existing devices to a novel focusing radiator concept and new photon detectors. The impact of including a precise measurement of the time of arrival of Cherenkov photons to increase the kinematical region over which particle identification can be performed is discussed. The progress in dedicated time-of-flight counters with recently developed very fast single photon detectors is also evaluated., Comment: Review talk at the VCI2007, Vienna, Feb. 2007

The use of a nonhomogeneous aerogel radiator, i.e. one consisting of layers with different refractive indices, has been shown to improve the resolution of the Cherenkov angle measured with a proximity focusing RICH detector. In order to obtain further information on the performance of such a detector, a simple model has been used to calculate the resolution and search for optimal radiator parameters., Comment: Submitted to Nucl. Instr. Meth