Progress towards a THGEM-based detector of single photons Alexeev, M.; Birsa, R.; Bradamante, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2011, Volume:
639, Issue:
1
Journal Article
Peer reviewed
The novel and robust Thick GEM (THGEM) electron multiplier, coupled to a solid state photon converter, represents a promising option for instrumenting, at affordable costs, large areas with photon ...detectors, in particular, in Cherenkov imaging counters where single photons must be detected with high efficiency. The main goal of our project is to demonstrate the feasibility of reliable gaseous detector of single photons based on the use of THGEM multipliers, able to stably operate at high gain and high rate and to build and validate a large size prototype of such a detector. The project status and perspectives are reported; in particular attention is dedicated to the simulation and laboratory studies performed to understand the photo-electron extraction performance attainable using a solid state coated photo-cathode film onto a THGEM substrate.
Cytomegalovirus (CMV) infection is a relevant cause of morbidity and mortality in transplantation patients. Its major incidence is in the first year and viral replication is related to acute ...rejection, survival reduction, and graft vascular disease.
This study aims to evaluate retrospectively whether a high dose of calcineurin inhibitors correlates with CMV-positive polymerase chain reaction (PCR), need for treatment, and death in cardiac transplantation patients.
This is a case-control study including patients who underwent transplantation between 2014 and 2016. They were separated into two groups (positive or negative PCR) and evaluated for dosage serum levels of cyclosporine and tacrolimus. Patients were classified with adequate dose of immunosuppressant or high dose, and was analyzed that there was any association with those and positive CMV-PCR, need for treatment for CMV, and deaths. For statistical analysis, the Student t test was used for the quantitative variables and the Fisher’s Exact Test for qualitative variables. To show CMV-free survival, the Kaplan-Meier curve was used. The level of significance was set at 5%.
CMV-positive PCR in the sample was 72% for a total of 50 individuals. Positive PCR correlated with a high dose of calcineurin inhibitors in a statistically significant way (P = .002), as did a high dose of cyclosporine (P = .004); however, a high dose of tacrolimus had no such association (P = .17). When a high dose was assessed with a need for treatment, the chance of needing treatment increased more than eight times (P = .024; odds ratio = 8.25; 95% CI = 1.33 to 51.26), which was different from results found with high-dose tacrolimus (P = 1.0). However, no significant association was found in relation to deaths.
Tacrolimus serum levels showed no association with CMV-PCR, which was different from serum cyclosporine, which showed association with CMV-PCR positivity, increasing the need for treatment approximately 8-fold, without association with death.
Axion search by laser-based experiment OSQAR Sulc, M.; Pugnat, P.; Ballou, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2013, Volume:
718
Journal Article
Peer reviewed
Open access
Laser-based experiment OSQAR in CERN is aimed to the search of the axions by two methods. The photon regeneration experiment is using two LHC dipole magnets of the length 14.3m and magnetic field ...9.5T equipped with an optical barrier at the end of the first magnet. It looks as light shining through the wall. No excess of events above the background was detected at this arrangement. Nevertheless, this result extends the exclusion region for the axion mass. The second method wants to measure the ultra-fine vacuum magnetic birefringence for the first time. An optical scheme with electro-optical modulator has been proposed, validated and subsequently improved. Cotton–Mouton constant for air was determined in this experiment setup.
Lead Tungstate (PbWO 4 , PWO) has become presently the most commonly used scintillator material for electromagnetic calorimetry in medium and high-energy physics. There exists substantial demand for ...future calorimeters such as the completion of the PANDA electromagnetic compatibility (EMC) as well as various detector projects under discussion at Jefferson Lab or Brookhaven National Laboratory in the United States. Nearly, 6700 crystals are missing for the barrel section of the PANDA-EMC since the successful mass production of PWO using the Czochralski method was stopped after bankruptcy of the Bogoroditsk Technical Chemical Plant (BTCP) in Russia. Intermediate research and development efforts with the Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai, China, as an existing producer exploiting the modified Bridgman method could not reach the required quality in a consistent manner. End of 2014, the CRYTUR (Turnov, Czech Republic) has restarted the development of lead tungstate based again on the Czochralski method with impressive progress. The modified and optimized technology has already produced full size samples of PWO-II quality. This paper will present a detailed status report on a first preproduction run of 89 crystals focusing on the achieved optical performance, light yield, kinetics, and temperature dependence and radiation hardness.
New photon detectors, based on the use of multi-anode photo-multiplier tubes coupled to individual lens telescopes and read out with a dedicated read-out electronics system, equip the central region ...of the Cherenkov imaging counter RICH-1 of the COMPASS experiment at CERN SPS. They are characterised by high photon yield, fast response and high rate capability and are successfully in operation since the 2006 COMPASS data taking. The photon detection system fully matches the expected performance.
The design and construction of the photon detectors are described in detail.
The hybrid MPGD-based photon detectors of COMPASS RICH-1 Agarwala, J.; Alexeev, M.; Azevedo, C.D.R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2020, Volume:
952
Journal Article
Peer reviewed
Open access
Novel gaseous detectors of single photons for RICH applications have been developed and installed on COMPASS RICH-1 in 2016, covering a total area of 1.4 m2. They have a hybrid architecture ...consisting of two staggered THGEM layers (one equipped with a CsI photoconverting layer) and a bulk Micromegas and operate stably and efficiently, providing a single photon angular resolution of ∼1.8 mrad and about 10 detected photons per ring at saturation. The main aspects of their construction, commissioning, characterization and performance are presented.
The two-photon exchange experiment at DESY Alarcon, R.; Beck, R.; Bernauer, J. C. ...
The European physical journal. A, Hadrons and nuclei,
04/2024, Volume:
60, Issue:
4
Journal Article
Peer reviewed
Open access
We propose a new measurement of the ratio of positron-proton to electron-proton elastic scattering at DESY. The purpose is to determine the contributions beyond single-photon exchange, which are ...essential for the Quantum Electrodynamic (QED) description of the most fundamental process in hadronic physics. By utilizing a 20 cm long liquid hydrogen target in conjunction with the extracted beam from the DESY synchrotron, we can achieve an average luminosity of
2.12
×
10
35
cm
-
2
·
s
-
1
(
≈
200
times the luminosity achieved by OLYMPUS). The proposed two-photon exchange experiment (TPEX) entails a commissioning run at a beam energy of 2 GeV, followed by measurements at 3 GeV, thereby providing new data up to
Q
2
=
4.6
(GeV/
c
)
2
(twice the range of current measurements). We present and discuss the proposed experimental setup, run plan, and expectations.
Mixed methods study design.
The Work Rehabilitation Questionnaire-Self-Report Version (WORQ-SELF) is an assessment tool based on the International Classification of Functioning, Disability and Health ...(ICF) developed to evaluate functioning in different patient populations in vocational rehabilitation (VR) settings. The objective of this study is to establish the content validity of WORQ-SELF in a subgroup of spinal cord injury (SCI) patients in the early post-acute context.
Swiss Paraplegic Research and Swiss Paraplegic Centre, Nottwil, Switzerland.
Contents of WORQ-SELF were compared with semi-guided interviews with SCI patients in Switzerland, the Comprehensive ICF Core Set for SCI early post-acute, and outcome instruments used in VR and SCI. A frequency analysis was performed.
WORQ-SELF represented 46 different ICF categories and of these 37 categories were confirmed by the patient interviews. The Comprehensive ICF Core Set for SCI confirmed 25 categories. Four instruments used in VR and SCI setting were identified. Contents of those instruments confirmed 14 categories of WORQ-SELF. Overall, 26 categories of the WORQ-SELF were confirmed by at least 2 of the 3 sources, 13 categories by 1 source and 7 were not confirmed by any of the sources.
The WORQ-SELF proved to have content validity for utility in patients with SCI within the context of VR. WORQ-SELF can be used to assess the functioning and disability of patients in the return to work process.
After pioneering gaseous detectors of single photon for RICH applications using CsI solid state photocathodes in MWPCs within the RD26 collaboration and by the constructions for the RICH detector of ...the COMPASS experiment at CERN SPS, in 2016 we have upgraded COMPASS RICH by novel gaseous photon detectors based on MPGD technology. Four novel photon detectors, covering a total active area of 1.5 m2, have been installed in order to cope with the challenging effciency and stability requirements of the COMPASS physics programme. They are the first application in an experiment of MPGD-based single photon detectors. All aspects of the upgrade are presented, including engineering, mass production, quality assessment and performance. Perspectives for further developments in the field of gaseous single photon detectors are also indicated.
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