In this study we assessed feasibility, weight loss results and recurrence of Gastro-Oesophageal Reflux Disease (GORD) in patients undergoing laparoscopic Roux-en-Y Gastric Bypass (RYGB) after ...previous anti-reflux surgery.
Retrospective analysis of prospectively collected data was performed for patients undergoing laparoscopic RYGB after previous anti-refux surgery between 1/1/2000 and 1/1/2015. Weight loss was assessed using %Excess Weight Loss (%EWL) and every patient was compared with two matched control subjects. Telephone interviews were conducted to assure maximum follow-up data. Quality Of Life (QOL) was assessed using the Gastro-Intestinal Quality of Life Index (GIQLI), Gastro-intestinal Symptom Rating Scale (GSRS) and Bariatric Analysis and Reporting Outcome System (BAROS).
A total of 18 patients (11 female, 7 male) were identified (17 Nissen and 1 former Belsey-Mark IV fundoplication). Mean time between surgical interventions was 9.4 years. Laparoscopic RYGB was feasible without intra-operative complications. One patient needed relaparoscopy for falsely suspected leakage and another suffered from postoperative pneumonia. Symptomatic GORD after RYGB was reported by 3 patients (16.7%). QOL was rated good with a GIQLI-score of 118 (range 97-140), GSRS score of 33 (range 15-59) and BAROS-score of 4,6 (range 1.2-6.8). EWL 3 years after surgery was comparable with matched control subjects (80.1% vs. 79.2% in controls, P=0.70).
Laparoscopic conversion of anti-reflux surgery to RYGB with breakdown of the fundoplication is feasible and safe. Weight loss results are equal to control subjects and treatment of GORD is good. No significant decrease in QOL was reported.
Performance of a prototype TORCH time-of-flight detector Bhasin, S.; Blake, T.; Brook, N.H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2023, Volume:
1050
Journal Article
Peer reviewed
Open access
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.
TORCH pattern recognition and particle identification performance Garcia Martin, L.M.; Blake, T.; Brook, N.H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2023, Volume:
1055
Journal Article
Peer reviewed
Open access
The TORCH detector aims to provide K/π (K/p) separation up to a momentum of about 10 (15) ▪ by measuring their time-of-flight at the LHCb detector. Prompt Cherenkov photons are produced in a quartz ...radiator bar of 10 mm thickness, and propagated via total internal reflection to the periphery of the detector, where they are focused onto an array of microchannel plate photomultipliers that measure the photon arrival time and position. Pattern recognition techniques are used to compare the likelihood that the detector image is due to a given particle hypothesis. Good performance is obtained even for very high detector occupancies.
Recent developments in vacuum-based photon detectors for single photon detection, in particular, innovative techniques such as position-sensitive hybrid photon detectors and photo-multiplier tubes, ...have stimulated increased interest from a variety of fields. These devices are sensitive to single photons with an energy spectrum defined by the transmission of the optical entrance window and the photo-cathode type. Their spatial resolution ranges from a few millimetres, for pad hybrid photon detectors and multi-anode photo-multiplier tubes, down to a few tens of microns for pixel hybrid photon detectors. Basic technological and design aspects are assessed in this paper. The performance of such devices in terms of gain, intrinsic speed, single- and multiple photon counting capability, active-to-total area ratio, and magnetic field sensitivity are discussed. Specific problems related to the particular front-end and readout electronics requirements are outlined. Examples of applications are given, and some current research and development programmes are presented.
The pixel Hybrid Photon Detector (HPD) has been developed to detect the light produced by the two Ring Imaging Cherenkov (RICH) detectors of the LHCb experiment. The device is a vacuum photon ...detector equipped with cross-focussing electron optics and a custom anode for photoelectron detection. The production of the 500 such devices that are required to cover the photon detection surface of the LHCb RICH detectors is ongoing. A pre-series of HPDs has been manufactured and their performance assessed in the laboratory. Successful operation has also been confirmed in a test beam. Accelerated ageing tests performed on one pre-series tube show no degradation of performance.
The TORCH detector R&D: Status and perspectives Gys, T.; Brook, N.; García, L. Castillo ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2017, Volume:
876
Journal Article
Peer reviewed
Open access
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.
The TORCH time-of-flight detector Harnew, N.; Gao, R.; Hadavizadeh, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2023, Volume:
1048
Journal Article
Peer reviewed
Open access
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 9.5m ...flight distance from the LHC interaction point. To achieve this level of performance, a 15ps timing resolution per track is required. A TORCH prototype module having a 1250×660×10mm3 fused-silica radiator plate and equipped with two MCP-PMTs has been tested in a 8GeV/c CERN test-beam. Single-photon time resolutions of between 70–100ps have been achieved, dependent on the beam position in the radiator. The measured photon yields agree with expectations.
Status of the TORCH time-of-flight project Harnew, N.; Bhasin, S.; Blake, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2020, Volume:
952
Journal Article
Peer reviewed
Open access
TORCH is a time-of-flight detector, designed to provide charged π∕K particle identification up to a momentum of 10GeV/c for a 10m 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 × 53mm2, 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 5GeV/c mixed pion/proton beam at the CERN PS facility. Preliminary results indicate that a single-photon resolution better than 100ps can be achieved. The expected performance of a full-scale TORCH detector for the Upgrade II of the LHCb experiment is also discussed.
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