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TORCH is a large-area time-of-flight (ToF) detector, proposed for the Upgrade-II of the LHCb experiment. It will provide charged hadron identification over a 2–20 GeV/c momentum range, given a 9.5 m flight distance from the LHC interaction point. To achieve this level of performance, a 15 ps timing resolution per track is required. A TORCH prototype module having a 1250 × 660 × 10 mm 3 fused-silica radiator plate and equipped with two MCP-PMTs has been tested in a 8 GeV/c CERN test-beam. Single-photon time resolutions of between 70–100 ps have been achieved, dependent on the beam position in the radiator. The measured photon yields agree with expectations. [ABSTRACT FROM AUTHOR]

Abstract: The vertex detectors at the International Linear Collider (ILC) (there will be two of them, one for each of two general purpose detectors) will certainly be built with silicon pixel detectors, either monolithic or perhaps vertically integrated. However, beyond this general statement, there is a wide range of options supported by active R&D programmes all over the world. Pixel-based vertex detectors build on the experience at the SLAC large detector (SLD) operating at the SLAC linear collider (SLC), where a 307Mpixel detector permitted the highest physics performance at LEP or SLC. For ILC, machine conditions demand much faster readout than at SLC, something like 20 time slices during the 1ms bunch train. The approach of the image sensor with in-situ storage (ISIS) is unique in offering this capability while avoiding the undesirable requirement of ‘pulsed power’. First results from a prototype device that approaches the pixel size of 20μm square, needed for physics, are reported. The dimensional challenge is met by using a 0.18μm imaging CMOS process, instead of a conventional CCD process. [ABSTRACT FROM AUTHOR]

Abstract TORCH (Timing Of internally Reflected CHerenkov photons) is a precision time-of-flight detector for particle identification at low momentum. It uses Cherenkov photons produced by charged particles passing through a quartz radiator plate. Some of these photons propagate by total internal reflection, they emerge at the edges and are subsequently focused onto photon detectors. The recorded positions and arrival times of the photons are used to precisely reconstruct their trajectory and propagation time in the quartz. This allows to determine the crossing time of the particles through the plate. The TORCH design requires the development of fast photon detectors with fine and asymmetric anode segmentation. The overall per-photon time precision must be better than 70 ps after signal processing and photon path reconstruction in the quartz. In addition, the photon detectors must survive several years of high illumination levels. The on-going R&D programme aims at demonstrating the TORCH basic concept through the realization of a detector module equipped with custom photon detectors featuring the required granularity and lifetime, with dedicated fast front-end electronics and with high-quality quartz radiator and focussing optics. This paper will report on the latest TORCH results achieved in the laboratory and in charged particle beam tests. It will also introduce the developments towards a full-scale module prototype. [ABSTRACT FROM AUTHOR]

Abstract TORCH is a novel time-of-flight detector that has been developed to provide charged-particle identification between 2 and 10 GeV/c momentum. TORCH combines arrival times from multiple Cherenkov photons produced within a 10 mm-thick quartz radiator plate, to achieve a 15 ps time-of-flight resolution per incident particle. A customised Micro-Channel Plate photomultiplier tube (MCP-PMT) and associated readout system utilises an innovative charge-sharing technique between adjacent pixels to obtain the necessary 70 ps time resolution of each Cherenkov photon. A five-year R&D programme has been undertaken, culminating in the construction of a small-scale prototype TORCH module. In testbeams at CERN, this prototype operated successfully with customised electronics and readout system. A full analysis chain has been developed to reconstruct the data and to calibrate the detector. Results are compared to those using a commercial Planacon MCP-PMT, and single photon resolutions approaching 80 ps have been achieved. The photon counting efficiency was found to be in reasonable agreement with a GEANT4 Monte Carlo simulation of the detector. The small-scale demonstrator is a precursor to a full-scale TORCH module (with a radiator plate of 660 × 1250 × 10 mm 3), which is currently under construction. [ABSTRACT FROM AUTHOR]

TORCH is a novel time-of-flight detector, designed to provide charged particle identification of pions, kaons and protons in the momentum range 2–20 GeV/ c over a 9.5 m flight path. A detector module, comprising a 10 mm thick quartz plate, provides a source of Cherenkov photons which propagate via total internal reflection to one end of the plate. Here, the photons are focused onto an array of custom-designed Micro-Channel Plate Photo-Multiplier Tubes (MCP-PMTs) which measure their positions and arrival times. The target time resolution per photon is 70 ps which, for 30 detected photons per charged particle, results in a 10 – 15 ps time-of-flight resolution. A 1.25 m length TORCH prototype module employing two MCP-PMTs has been developed, and tested at the CERN PS using a charged hadron beam of 8 GeV/ c momentum. The construction of the module, the properties of the MCP-PMTs and the readout electronics are described. Measurements of the collected photon yields and single-photon time resolutions have been performed as a function of particle entry points on the plate and compared to expectations. These studies show that the performance of the TORCH prototype approaches the design goals for the full-scale detector. [ABSTRACT FROM AUTHOR]

TORCH is a time-of-flight detector that is being developed for the Upgrade II of the LHCb experiment, with the aim of providing charged particle identification over the momentum range 2–10 GeV/ c. A small-scale TORCH demonstrator with customised readout electronics has been operated successfully in beam tests at the CERN PS. Preliminary results indicate that a single-photon resolution better than 100 ps can be achieved. [ABSTRACT FROM AUTHOR]

TORCH is a large-area precision time-of-flight detector based on the DIRC principle. The DIRC bar boxes of the BaBar experiment at SLAC could possibly be reused to form a part of the TORCH detector time-of-flight wall area, proposed to provide positive particle identification of low momentum kaons in the LHCb experiment at CERN. For a potential integration of BaBar bar boxes into TORCH, new imaging readout optics are required. From the several designs of readout optics that have been considered, two are used in this paper to study the effect of BaBar bar optical imperfections on the detector reconstruction performance. The kaon-pion separation powers obtained from analysing simulated photon hit patterns show the performance reduction for a BaBar bar of non-square geometry compared to a perfectly rectangular cross section. [ABSTRACT FROM AUTHOR]

TORCH (Timing Of internally Reflected CHerenkov photons) is a time-of-flight detector for particle identification at low momentum. It has been originally proposed for the LHCb experiment upgrade. TORCH is using plates of quartz radiator in a modular design. A fraction of the Cherenkov photons produced by charged particles passing through this radiator propagate by total internal reflection, they emerge at the edges and are subsequently focused onto fast, position-sensitive single-photon detectors. The recorded position and arrival time of the photons are used to precisely reconstruct their trajectory and propagation time in the quartz. The on-going R&D programme aims at demonstrating the TORCH basic concept through the realization of a full detector module and has been organized on the following main development lines: micro-channel plate photon detectors featuring the required granularity and lifetime, dedicated fast front-end electronics preserving the picosecond timing information provided by single photons, and high-quality quartz radiator and focussing optics minimizing photon losses. The present paper reports on the TORCH results successfully achieved in the laboratory and in charged particle beam tests. It will also introduce the latest developments towards a final full-scale module prototype. [ABSTRACT FROM AUTHOR]

The TORCH time-of-flight (TOF) detector is being developed to provide particle identification up to a momentum of 10 GeV/c over a flight distance of 10 m. It has a DIRC-like construction with 10 mm thick synthetic amorphous fused-silica plates as a Cherenkov radiator. Photons propagate by total internal reflection to the plate periphery where they are focused onto an array of customised position-sensitive micro-channel plate (MCP) detectors. The goal is to achieve a 15 ps time-of-flight resolution per incident particle by combining arrival times from multiple photons. The MCPs have pixels of effective size 0.4 mm×6.6 mm 2 in the vertical and horizontal directions, respectively, by incorporating a novel charge-sharing technique to improve the spatial resolution to better than the pitch of the readout anodes. Prototype photon detectors and readout electronics have been tested and calibrated in the laboratory. Preliminary results from testbeam measurements of a prototype TORCH detector are also presented. [ABSTRACT FROM AUTHOR]

TORCH is a large-area and high-precision time-of-flight detector, designed to provide charged particle identification over a 2–20 GeV/c momentum range. The TORCH detector comprises a 10 mm thick quartz radiator, instrumented with photon detectors, which precisely time and measure the arrival positions of the Cherenkov photons. The photon detectors are micro-channel plate photo-multiplier tubes (MCP-PMTs) comprising a finely segmented anode of 64 × 64 anode pads, electronically ganged into 64 × 8 pixels, over a 53 × 53 mm 2 area, an excellent intrinsic time resolution of ∼ 30 ps, and a long lifetime of up to ≳ 5 C/cm 2. The current version of the MCP-PMTs used by TORCH have been developed with an industrial partner, Photek Ltd, to satisfy the stringent requirements of the detector. The TORCH R&D programme has successfully demonstrated the detector concept through extensive laboratory and beam tests. A TORCH prototype has been constructed and has yielded encouraging results when exposed to low momentum charged hadrons. Characteristic patterns of Cherenkov photons have been recorded, illustrating the required spatial accuracy and timing resolution of 70 ps per photon. Both laboratory and beam test results are approaching the design goals of the TORCH detector. [ABSTRACT FROM AUTHOR]

TORCH is a large-area, high-precision time-of-flight (ToF) detector designed to provide charged-particle identification in the 2–20 GeV/ c momentum range. Prompt Cherenkov photons emitted by charged hadrons as they traverse a 10 mm quartz radiator are propagated to the periphery of the detector, where they are focused onto an array of micro-channel plate photomultiplier tubes (MCP-PMTs). The position and arrival times of the photons are used to infer the particles' time of entry in the radiator, to identify hadrons based on their ToF. The MCP-PMTs were developed with an industrial partner to satisfy the stringent requirements of the TORCH detector. The requirements include a finely segmented anode, excellent time resolution, and a long lifetime. Over an approximately 10 m flight distance, the difference in ToF between a kaon and a pion with 10 GeV/ c momentum is 35 ps, leading to a 10–15 ps per track timing resolution requirement. On average 30 photons per hadron are detected, which translates to a single-photon time resolution of 70 ps. The TORCH R&D program aims to demonstrate the validity of the detector concept through laboratory and beam tests, results from which are presented. A timing resolution of 70–100 ps was reached in beam tests, approaching the TORCH design goal. Laboratory timing tests consist of operating the MCP-PMTs coupled to the TORCH readout electronics. A time resolution of 50 ps was measured, meeting the TORCH target timing resolution. [ABSTRACT FROM AUTHOR]

The TORCH time-of-flight detector is being developed to provide particle identification between 2 and 10 GeV/ c momentum over a flight distance of 10 m. TORCH is designed for large-area coverage, up to 30 m 2 , and has a DIRC-like construction. The goal is to achieve a 15 ps time-of-flight resolution per incident particle by combining arrival times from multiple Cherenkov photons produced within quartz radiator plates of 10 mm thickness. A four-year R&D programme is underway with an industrial partner (Photek, UK) to produce 53×53 mm 2 Micro-Channel Plate (MCP) detectors for the TORCH application. The MCP-PMT will provide a timing accuracy of 40 ps per photon and it will have a lifetime of up to at least 5 Ccm −2 of integrated anode charge by utilizing an Atomic Layer Deposition (ALD) coating. The MCP will be read out using charge division with customised electronics incorporating the NINO chipset. Laboratory results on prototype MCPs are presented. The construction of a prototype TORCH module and its simulated performance are also described. [ABSTRACT FROM AUTHOR]

The Time Of internally Reflected Cherenkov light (TORCH) detector is under development. Charged particle tracks passing through a 1 cm plate of quartz will generate the Cherenkov photons, and their arrival will be timed by an array of micro-channel plate photon detectors. As part of the TORCH R&D studies, commercial and custom-made micro-channel plate detectors are being characterized. The final photon detectors for this application are being produced in a three-phase program in collaboration with industry. Custom-made single-channel devices with extended lifetime have been manufactured and their performance is being systematically investigated in the laboratory. Optical studies for the preparation of beam and laboratory tests of a TORCH prototype are also underway. [ABSTRACT FROM AUTHOR]

TORCH is an innovative high-precision time-of-flight system to provide particle identification in the difficult intermediate momentum region up to 10 GeV/ c . It is also suitable for large-area applications. The detector provides a time-of-flight measurement from the imaging of Cherenkov photons emitted in a 1 cm thick quartz radiator. The photons propagate by total internal reflection to the edge of the quartz plate and are then focused onto an array of photon detectors at the periphery. A time-of-flight resolution of about 10–15 ps per incident charged particle needs to be achieved to allow a three sigma kaon-pion separation up to 10 GeV/ c momentum for the TORCH located 9.5 m from the interaction point. Given ~ 30 detected photons per incident charged particle, this requires measuring the time-of-arrival of individual photons to about 70 ps. This paper will describe the design of a TORCH prototype involving a number of ground-breaking and challenging techniques. [ABSTRACT FROM AUTHOR]

Abstract: The Linear Collider Flavour Identification (LCFI) Collaboration is developing the sensors, readout electronics and mechanical support structures for the vertex detector of the International Linear Collider (ILC). High speed readout is needed to ensure that the occupancy due to the pair production background at the ILC is kept below the 1% level. In order to satisfy this requirement, Column Parallel CCDs (CPCCDs), Column Parallel Readout chips (CPRs) and Column Parallel Driver chips (CPDs) have been developed. The CPCCD has to operate at a clock frequency of 50MHz, which represents a difficult technical challenge due to the large sensor capacitance. The design and performance of the second generation CPCCD sensors, CPC2, and the new driver chip, CPD1, which meet these challenging requirements, are described. [ABSTRACT FROM AUTHOR]

Abstract: The LCFI Collaboration is developing the sensors, readout electronics and mechanical support structures for the Vertex Detector (VXD) of the International Linear Collider (ILC). High-speed readout is needed to ensure that the occupancy due to the pair production background at the ILC is kept below 1% level. In order to satisfy this requirement, Column Parallel CCDs (CPCCDs) and Column Parallel Readout chips (CPRs) have been developed. The CPCCD has to operate at a clock frequency of 50MHz, which represents a difficult technical challenge due to the relatively large sensor capacitance. The design and performance of planar transformers, which can be used to provide the required 20A clock current, are described. [Copyright &y& Elsevier]

Abstract: The Linear Collider Flavour Identification (LCFI) collaboration has successfully developed the first prototype of a novel particle detector, the In-situ Storage Image Sensor (ISIS). This device ideally suits the challenging requirements for the vertex detector at the future International Linear Collider (ILC), combining the charge storing capabilities of the Charge-Coupled Devices (CCD) with readout commonly used in CMOS imagers. The ISIS avoids the need for high-speed readout and offers low power operation combined with low noise, high immunity to electromagnetic interference and increased radiation hardness compared to typical CCDs. The ISIS is one of the most promising detector technologies for vertexing at the ILC. In this paper we describe the measurements on the charge-shielding properties of the p-well, which is used to protect the storage register from parasitic charge collection and is at the core of device''s operation. We show that the p-well can suppress the parasitic charge collection by almost two orders of magnitude, satisfying the requirements for the application. [Copyright &y& Elsevier]

Abstract: The In Situ Storage Image Sensor (ISIS) is a monolithic active pixel sensor with memory cells in each pixel. The memory cells are implemented as a CCD register. A test device with parameters suitable for tracking charged particles has been constructed and characterized. The characteristics of a proof-of-principle ISIS device are described and results from using the sensor as a tracking device for high energy electrons are presented. [Copyright &y& Elsevier]

Abstract: The in situ storage image sensor (ISIS) is a monolithic active pixel sensor with memory cells in each pixel. The memory cells are implemented as a CCD register. This and other features of the sensor make the ISIS an excellent device for detectors that will be used at the International linear collider (ILC), an electron-positron accelerator with a proposed centre-of-mass energy of around 500GeV. The sensor can be made very thin while retaining a high signal-to-noise ratio. The memory cells can be read out between bunch trains at a relatively low clock speed, hence limiting power consumption. The actual signal charge is stored in potential wells and not on capacitors, minimizing the sensitivity to electromagnetic interference. This paper presents the results of the first beam test of the first ISIS prototype. The measurements made include the signal-to-noise ratio, position resolution and efficiency. [Copyright &y& Elsevier]

TORCH is a time-of-flight detector designed to perform particle identification over the momentum range 2–10 GeV/ c for a 10 m flight path. The detector exploits prompt Cherenkov light produced by charged particles traversing a quartz plate of 10 mm thickness. Photons are then trapped by total internal reflection and directed onto a detector plane instrumented with customised position-sensitive Micro-Channel Plate Photo-Multiplier Tube (MCP-PMT) detectors. A single-photon timing resolution of 70 ps is targeted to achieve the desired separation of pions and kaons, with an expectation of around 30 detected photons per track. Studies of the performance of a small-scale TORCH demonstrator with a radiator of dimensions 120 × 350 × 10 mm 3 have been performed in two test-beam campaigns during November 2017 and June 2018. Single-photon time resolutions ranging from 104. 3 ps to 114. 8 ps and 83. 8 ps to 112. 7 ps have been achieved for MCP-PMTs with granularity 4 × 64 and 8 × 64 pixels, respectively. Photon yields are measured to be within ∼ 10% and ∼ 30% of simulation, respectively. Finally, the outlook for future work with planned improvements is presented. [ABSTRACT FROM AUTHOR]

The TORCH time-of-flight detector is designed to provide particle identification in the momentum range 2 − 10 GeV∕c over large areas. The detector exploits prompt Cherenkov light produced by charged particles traversing a 10 mm thick quartz plate. The photons propagate via total internal reflection and are focused onto a detector plane comprising position-sensitive Micro-Channel Plate Photo-Multiplier Tubes (MCP-PMT) detectors. The goal is to achieve a single-photon timing resolution of 70 ps , giving a timing precision of 15 ps per charged particle by combining the information from around 30 detected photons. The MCP-PMT detectors have been developed with a commercial partner (Photek Ltd, UK), leading to the delivery of a square tube of active area 53 × 53 mm 2 with a granularity of 8 × 128 pixels equivalent. A large-scale demonstrator of TORCH, having a quartz plate of dimensions 660 × 1250 × 10 mm 3 and read out by a pair of MCP-PMTs with custom readout electronics, has been verified in a test beam campaign at the CERN PS. Preliminary results indicate that the required performance is close to being achieved. The anticipated performance of a full-scale TORCH detector at the LHCb experiment is presented. [ABSTRACT FROM AUTHOR]

TORCH is a time-of-flight detector, designed to provide charged π ∕ K particle identification up to a momentum of 10 GeV/c for a 10 m flight path. To achieve this level of performance, a time resolution of 15 ps per incident particle is required. TORCH uses a plane of quartz of 1 cm thickness as a source of Cherenkov photons, which are then focussed onto square Micro-Channel Plate Photomultipliers (MCP-PMTs) of active area 53 × 53 mm 2 , segmented into 8 × 128 pixels equivalent. A small-scale TORCH demonstrator with a customised MCP-PMT and associated readout electronics has been successfully operated in a 5 GeV/c mixed pion/proton beam at the CERN PS facility. Preliminary results indicate that a single-photon resolution better than 100 ps can be achieved. The expected performance of a full-scale TORCH detector for the Upgrade II of the LHCb experiment is also discussed. [ABSTRACT FROM AUTHOR]

Timing Of internally Reflected CHerenkov photons (TORCH) is a time-of-flight detector proposed for particle identification at low momentum. Charged particles passing through a plane of quartz produce Cherenkov light, some of which is trapped within the plane by total internal reflection and then emerges at the edges. There the photons are focused onto micro-channel plate photon detectors that register their position and arrival time. This allows reconstructing the photon trajectories in quartz and determining the particle crossing time. Commercial micro-channel plate tubes can achieve the required timing resolution, but their anode spatial segmentation is too coarse, at least in one dimension. In addition, these devices must survive a number of years in a high occupancy environment. Micro-channel plate tubes specifically dedicated to the TORCH are currently being designed, constructed and prototyped in collaboration with industry. In the present paper, results from commercial and dedicated devices are reported. [ABSTRACT FROM AUTHOR]