Despite advances in the performance of solid state photon counting devices, microchannel plate (MCP) photomultipliers remain the technology of choice for sub-200 picosecond event timing used in applications in particle and nuclear physics, and have application in other fields including life sciences, biological microscopy, for remote sensing and surveillance, materials analysis, fusion physics and space science instrumentation. Current MCP photomultiplier designs have performance limitations which restrict their application. These are (i) limited maximum count rate, and (ii) limited detector lifetime. We propose to add a gain stage behind the MCP stack by coating the anode with secondary electron emitting material, and collecting the charge on a mesh between the anode readout interface and MCP. An extra gain stage providing an amplification of ~10 would lower the gain required in the MCP stack by an order of magnitude, increasing both the local and global count rate limits imposed by the MCP and would further enhance the detector lifetime beyond that achieved by MCPs. The technique can be used with both conventional multi-anodes and the Image Charge technique can easily be adapted to provide gain by converting its resistive layer to a high emission dynode and inserting a transparent conductive mesh between MCP and dynode to act as an anode. Suitable materials for a dynode material such as SiO2, Si3N4, Al2O3, MgO and BaO would be subject to charge-up. However ALD coating can overcome this problem by layering dopant materials to control the material resistivity. A key issue in the proposed development is the deposition of thin film coatings with a tailored combination of electrical sheet resistance (100kohm per square - 100Mohm per square) and secondary electron emission. Candidate materials include alumina, magnesia and zinc oxide in their doped and pure compositions. ALD will be used in this project to prepare films on the MCP-dynode assemblies to be developed. ALD is a batch manufacturing process capable of highly conformal, pin-hole free and large area coatings. The technique has become a core manufacturing process for the deposition of 'high-k' dielectrics in current computer processor and memory devices where atomic control of thickness and uniformity is needed. The Space Research Centre, University of Leicester, has long record of successful collaboration with Photek Ltd. focussed on development and commercialisation of novel concepts and techniques for photon counting, imaging detector systems. Photek have existing links with Professor Chalker at Liverpool and the proposed collaboration has already manufactured, characterised and tested a preliminary batch of ALD-coated samples which has provides promising technical justification for this proposal. This collaboration has identified a novel technique of applying ALD coatings to enhance MCP photomultiplier dynamic range and lifetime which is patentable and highly complementary to existing devices. We have made preliminary measurements of candidate ALD coatings manufactured by Liverpool, demonstrated proof-of-concept of the image charge dynode/mesh anode gain technique in an MCP detector, and made a patent application to protect our IP. We envisage that this technique, by providing significant detector dynamic range and lifetime benefits, will give Photek considerable advantage as detector providers for new projects at sLHC and FAIR. In addition the technique is applicable to many MCP-based photomultiplier designs for which there are significant markets in other areas including in fusion physics, remote sensing, life sciences, from biological R&D to clinical diagnostics, materials analysis and planetary science.

Medical imaging has long benefited from advances in photon counting detectors arising from particle and space physics e.g. radiometric tracer techniques, including gamma scintigraphy, and PET. Other advances in photon science over the last few decades have migrated to applications in medical imaging, albeit with lower spatial resolution, such as photonic measurement of ultrasound, NMR, EPR and dielectric spectroscopies, as well as Raman and fluorescence. The genomics revolution of the past 15 years, exemplified by the high profile Human Genome Project, has been fuelled by technologies wholly reliant on intensity based fluorescence measurements. These methods are generally only quantitative in a fluidic automation context, a method that is not applicable to the quantitative complex cell biology measurements required for the next major holy grail of biomedical research, the proteomic revolution; the much more complicated study of proteins in vivo which is still in its infancy. This project aims to develop a detector system specifically designed to address the requirements of optical proteomics; to be capable of high content analysis at high throughput. The goal is to integrate a multi-channel, high time resolution, photon counting system into a single miniaturized detector system with integrated electronics (>99% smaller per pixel), an engine for the next generation of biomedical tools. Existing time resolved methods which allow high content assays to be performed are not compatible with high throughput methods: each measurement takes minutes and costs £25k / £50k per spatially resolved element (pixel). In comparison, conventional high throughput cell biological assays are limited to low content analysis. However this device, with its capability for high time resolution (20 ns), and multi-channel parallel analysis (up to 384 channels), will allow high content (multi-parametric) analysis to be undertaken at high throughput in a highly flexible and economic way (<1% of the cost per pixel). The high level of integration allows easy reconfigurability, so an objective choice can be made in the trade-off between throughput and content to match a variety of specific applications, without loss of overall performance and within a high dynamic range envelope. Applications of this technology include (in order of increasing likelihood of market capture) :- 1) High volume technology for point-of-care diagnostics. This device, with the underlying simplicity of a relatively simple vacuum tube design and low cost ASIC and FPGA electronics, could be the precursor to a mass produced, affordable device with high specificity for point of care clinical diagnostics, which would command a high volume market. 2) Optical Tomography. Very high time resolution, coupled with high throughput and dynamic range make this device a suitable tool for optical tomography, a technique suitable for niche applications such as neo-natal and breast imaging where other techniques, such as using ionizing radiation etc., are undesirable. 3) High content cell biology for tissue microarrays. The high throughput of this device will greatly speed up analysis of samples in tissue microarrays, a widely used technique with applications such as drug screening and toxicology. 4) Ubiquitous, high performance, fluorescence lifetime imaging tool. This device will provide a cost effective (<1% of the cost per pixel) high technology tool for fluorescence lifetime imaging, providing enhanced performance over existing systems, and affordable by all life science laboratories.

Future experiments in nuclear, hadronic and particle physics rely on the identification and complete, precise determination of the four-momentum vector of all reaction products. Imaging Cherenkov detector are an invaluable tool in providing this information. Charged particle traversing a dielectric medium with a speed greater than the speed of light inside the medium emit a come of Cherenkov radiations. The opening angle of this cone is (for a given refractive index of the radiator medium) a measure of the particles's velocity. This provides, combined with an independent moment measurement, a powerful method to infer the mass of the particle in question. Imaging Cherenkov detectors current under development can be categories in two classes, classical Ring Imaging CHerenkov (RICH) counters and counters using the Detection of Internally Reflected Cherenkov light (DIRC). The RICH principle uses the light emitted from the radiator into an expansion volume to image the Cherenkov cone, while the DIRC principle relies on the optical properties of the radiator itself to propagate the light internally towards a photon detection array. The latter technique is also studied for energy and time-of-flight measurements. The UK nuclear physics community is involved in three exciting new detector developments for precision studies of the strong interaction, the PANDA disc DIRC, the upgrade of the CLAS 12 detector with an Aerogel RICH and conceptual studies for the DIRC detector at a future electron-ion collider EIC. The nuclear physics group at the University of Glasgow is leading the development of the PANDA disc DIRC and the development and testing of the photon detection system for the CLAS 12 RICH. These detector systems rely on segmented, high rate and high granularity, single photon capable detection devices. All detector systems will have to operate within or in the vicinity of a strong magnetic field. Their photon detection systems require a large filling fraction and a compact geometry. Our current and previous tests demonstrated that none of the available commercial solutions fulfil the criteria for future Cherenkov counters in nuclear and particle physics. We propose to develop and test a new generation of photon detectors together with research and industrial partners in the UK, Kelvin Nanotechnology, Kelvin/Rutherford laboratory and Photek. The project comprised test of gain, homogeneity, rate dependence, time resolution, cathode lifetime and photon detection efficiency. These studies will be complemented by simulation studies of the detectors themselves and their properties in applications. The performance will be tested in laboratories at Photek and the University of Glasgow and by using existing Cherenkov prototypes in electron and hadron beams at the University of Strathclyde, GSI and CERN. The principal investigator of this project is leading the European Joint Research Activity "CherenkovImaging" which complements the proposed research e.g. for applications at COSY, Juelich, Germany. Furthermore we are closely collaborating with UK institutions involved in the TORCH project, a proposed upgrade of the LHCb detector based on adapting the PANDA disc DIRC design to time-of-flight measurements, and the ATLAS Forward Physics group. The properties of the photon detection system investigated are of great interest beyond the boundaries of fundamental nuclear and particle physics research. Its application in future medical imaging modalities like Time-of-Flight PET or PET/MRI fusion, is obvious. Less obvious, but potentially equally important, it could greatly enhance the current capabilities of studying time resolved fluorescence phenomena in cell research and other life-science applications. THe principle investigator and his group are currently conducting a pilot study into these applications in collaboration with the Beatson Institute for Cancer Research.

A variety of sensor types have been operated in electron bombarded mode, including CCDs CMOS sensors, and silicon sensors (pixellated photodiodes) in conjunction with active pixel sensors (e.g. Medipix [2]). This project aims to develop a photon counting capability for the TDCpix [3], a newly developed pixel sensor with exceptional timing resolution. It follows on from a previous PIPSS and BBSRC-funded collaboration with CERN to develop a multi-channel photon-counting detectors with picosecond event timing for life science applications. Our original IPS project utilized a microchannel plate detector with CERN-developed preamplifier and time-to-digital ASICs. The recent development of the TDCpix active pixel sensor by the same group at CERN offers comparable time resolution (100 ps binning, and electronic resolution ~30ps) but with a much higher pixel count (40 x 45 pixel2, 12 x 13.5 mm2), a much higher level of miniaturization provided by integration of the entire electronics on to the chip, and a greatly increased overall count rate capability of ~130 Mcount/s per ASIC, an order of magnitude higher per unit area than its microchannel plate based predecessor. An electron bombarded TDCpix would offer unrivalled performance with commercial potential for applications using time-correlated single photon counting (TCSPC) such as high content cell screening and other expanding fields in the life science sector, LIDAR instruments for remote sensing, and a variety of other event timing applications where only small arrays of individual photomultiplier tubes are the norm. Our aim in this project is to identify and develop a technology for photon counting detectors using electron bombarded silicon devices, in order to remove the active pixel sensor from within the vacuum tube, thus greatly simplifying design, de-risking the manufacturing process, and enhancing performance. Removing the chip from the tube will eliminate undesirable elements such as high density vacuum electrical feedthroughs, materials with poor vacuum compatibility, and internal bump, wire, and chip bonding, and will lift the restrictions imposed by these on tube processing which impact manufacturing yield, device reliability, and ultimately, sensor lifetime. Given a successful outcome to this project, we intend to propose a follow-on IPS project, one of whose goals would be to incorporate an additional, relatively low (x20) gain stage using a linear mode electron avalanche process within each pixel of the silicon sensor, matched to the requirements of electron bombarded operation. This will allow the electron bombardment gain to be lowered, reducing the tube operating voltage to safer levels, and reducing the lifetime-threatening radiation damage. The other elements of an electron bombarded detector design, the vacuum tube including photocathode, and the silicon sensor, will be provided by our industrial collaborators; Photek Ltd., and Micron Semiconductor Ltd, respectively. Photek have extensive experience of design and manufacture of custom vacuum-based detectors with specific expertise in the electron bombarded mode devices, having manufactured an electron bombarded Medipix-based detector. Micron Semiconductor have substantial experience and heritage producing large quantities of custom pixellated silicon sensors for harsh radiation environments at CERN LHC and other similar experiments. Specifically for this project, they have developed a thin entrance window technology which is highly desirable for electron bombarded mode to minimize photoelectron energy loss. The thickness of their currently available Type-9.5 window is 500 Angstroms, and a Type-10 window is under development with a thickness goal of 200 Angstroms. Micron also have a bump-bonding capability necessary for the interconnect development.

Despite advances in the performance of solid state photon counting devices, microchannel plate (MCP) photomultipliers remain the technology of choice for sub-200 picosecond event timing used in applications in particle and nuclear physics, and have application in other fields including life sciences, biological microscopy, for remote sensing and surveillance, materials analysis, fusion physics and space science instrumentation. Current MCP photomultiplier designs have performance limitations which restrict their application. These are (i) limited maximum count rate, and (ii) limited detector lifetime. We propose to add a gain stage behind the MCP stack by coating the anode with secondary electron emitting material, and collecting the charge on a mesh between the anode readout interface and MCP. An extra gain stage providing an amplification of ~10 would lower the gain required in the MCP stack by an order of magnitude, increasing both the local and global count rate limits imposed by the MCP and would further enhance the detector lifetime beyond that achieved by MCPs. The technique can be used with both conventional multi-anodes and the Image Charge technique can easily be adapted to provide gain by converting its resistive layer to a high emission dynode and inserting a transparent conductive mesh between MCP and dynode to act as an anode. Suitable materials for a dynode material such as SiO2, Si3N4, Al2O3, MgO and BaO would be subject to charge-up. However ALD coating can overcome this problem by layering dopant materials to control the material resistivity. A key issue in the proposed development is the deposition of thin film coatings with a tailored combination of electrical sheet resistance (100kohm per square - 100Mohm per square) and secondary electron emission. Candidate materials include alumina, magnesia and zinc oxide in their doped and pure compositions. ALD will be used in this project to prepare films on the MCP-dynode assemblies to be developed. ALD is a batch manufacturing process capable of highly conformal, pin-hole free and large area coatings. The technique has become a core manufacturing process for the deposition of 'high-k' dielectrics in current computer processor and memory devices where atomic control of thickness and uniformity is needed. The Space Research Centre, University of Leicester, has long record of successful collaboration with Photek Ltd. focussed on development and commercialisation of novel concepts and techniques for photon counting, imaging detector systems. Photek have existing links with Professor Chalker at Liverpool and the proposed collaboration has already manufactured, characterised and tested a preliminary batch of ALD-coated samples which has provides promising technical justification for this proposal. This collaboration has identified a novel technique of applying ALD coatings to enhance MCP photomultiplier dynamic range and lifetime which is patentable and highly complementary to existing devices. We have made preliminary measurements of candidate ALD coatings manufactured by Liverpool, demonstrated proof-of-concept of the image charge dynode/mesh anode gain technique in an MCP detector, and made a patent application to protect our IP. We envisage that this technique, by providing significant detector dynamic range and lifetime benefits, will give Photek considerable advantage as detector providers for new projects at sLHC and FAIR. In addition the technique is applicable to many MCP-based photomultiplier designs for which there are significant markets in other areas including in fusion physics, remote sensing, life sciences, from biological R&D to clinical diagnostics, materials analysis and planetary science.