The KM3NeT multi-PMT optical module Alshamsi, M.; Alves Garre, S.; Aly, Z. ...
Journal of instrumentation,
07/2022, Letnik:
17, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Abstract
The optical module of the KM3NeT neutrino telescope is an
innovative multi-faceted large area photodetection module. It
contains 31 three-inch photomultiplier tubes in a single 0.44 m
...diameter pressure-resistant glass sphere. The module is a sensory
device also comprising calibration instruments and electronics for
power, readout and data acquisition. It is capped with a
breakout-box with electronics for connection to an electro-optical
cable for power and long-distance communication to the onshore
control station. The design of the module was qualified for the
first time in the deep sea in 2013. Since then, the technology has
been further improved to meet requirements of scalability,
cost-effectiveness and high reliability. The module features a
sub-nanosecond timing accuracy and a dynamic range allowing the
measurement of a single photon up to a cascade of thousands of
photons, suited for the measurement of the Cherenkov radiation
induced in water by secondary particles from interactions of
neutrinos with energies in the range of GeV to PeV. A distributed
production model has been implemented for the delivery of more than
6000 modules in the coming few years with an average production rate
of more than 100 modules per month. In this paper a review is
presented of the design of the multi-PMT KM3NeT optical module with
a proven effective background suppression and signal recognition and
sensitivity to the incoming direction of photons.
A
bstract
Studying atmospheric neutrino oscillations in the few-GeV range with a multi-megaton detector promises to determine the neutrino mass hierarchy. This is the main science goal pursued by the ...future KM3NeT/ORCA water Cherenkov detector in the Mediterranean Sea. In this paper, the processes that limit the obtainable resolution in both energy and direction in charged-current neutrino events in the ORCA detector are investigated. These processes include the composition of the hadronic fragmentation products, the subsequent particle propagation and the photon-sampling fraction of the detector. GEANT simulations of neutrino interactions in seawater produced by GENIE are used to study the effects in the 1-20 GeV range. It is found that fluctuations in the hadronic cascade in conjunction with the variation of the inelasticity
y
are most detrimental to the resolutions. The effect of limited photon sampling in the detector is of significantly less importance. These results will therefore also be applicable to similar detectors/media, such as those in ice.
Summary
Swallowing is a muscular activity that occurs both after mastication and spontaneously as a result of saliva accumulation. Spontaneous saliva swallowing occurs about every 2 minutes. ...Comprehension of its functional mechanisms is relevant to assess their modification in clinical situations. A standardised surface electromyographical (ssEMG) protocol for the evaluation of this muscle activity is lacking. Aims of the present study are: (i) to determine the reproducibility of a ssEMG protocol for the evaluation of the oral phase of saliva swallowing and (ii) to evaluate the activity of masseter (MM), anterior temporalis (TA), submental muscles (SM) to draw a reference model of swallowing. Standardised surface electromyographical activity of MM, TA and SM during swallowing of saliva spontaneously accumulated was recorded in 20 healthy participants. Functional indexes including symmetry (POC), recruitment (Impact), duration of activation of each couple of muscles and of the whole exercise, position, intensity of the spike were computed. Inter‐ and intra‐appointment reliabilities were assessed and method errors calculated. Descriptive statistics, sex‐ and muscles‐related comparisons were carried out. Standardised surface electromyographical assessment of MM, TA and SM muscles was reliable. A high inter‐individual variability was found. Percentage overlapping coefficient (POC) values were close to 80% for TA and SM, higher than for MM (P < .001). Impact values ranged between 16.4% and 30.7%, and differences were found between muscles (P < .001). The global muscle activity during swallowing lasted between 1.5 and 1.8 seconds. For each couple of muscles, the duration of activation ranged between 0.7 and 1.6 seconds and muscles‐related differences were found (P < .001). The spike of activation for each couple of muscle ranged between 35.7% and 44.2% of the duration. The protocol was reliable and intra‐participants repeatable measures can be carried out. Due to the high inter‐participants variability, further analyses are needed to draw a model of muscular activity.
Purpose
This paper explores the feasibility of a new therapy for the treatment of hypospadias patients. Hypospadias is a very common congenital malformation of male genitals, with very high rate of ...recurrences after surgery. The field of regenerative medicine, which offers innovative solutions for many pathologies, still does not offer reliable solution for this pathology. Here, we propose quality, safety, and clinical feasibility assessment for an oral mucosa advanced therapy medicinal product (ATMP) grown on a biocompatible scaffold for a clinical study on urethral reconstruction of hypospadias patients.
Methods
Urethral and oral mucosal epithelia from donor biopsies were cultivated between two fibrin layers, under clinical-grade conditions for cell and tissue characterization and comparison, aimed at tissue engineering. In addition, single-clone analyses were performed to analyze gene expression profiles of the two epithelia by microarray technology.
Results
Oral mucosa appeared suitable for urethral reconstruction. The resulting ATMP was proven to maintain stem cells and regenerative potency. The preclinical safety studies were performed on human tissues to assess abnormalities and tumorigenicity, and confirmed the safety of the ATMP. Finally, the patient selection and the clinical protocol for the upcoming clinical trial were defined.
Conclusions
Against this backdrop, in this paper, we are proposing a new reproducible and reliable ATMP for the treatment of hypospadias.
Silicon detectors with intrinsic charge amplification implementing a n++-p+-p structure are considered as a sensor technology for future tracking and timing applications in high energy physics ...experiments. The performance of the intrinsic gain in Low Gain Avalanche Detectors (LGAD) after irradiation is crucial for the characterization of radiation hardness and timing properties in this technology. LGAD devices irradiated with reactor neutrons or 800 MeV protons reaching fluences of 2.3×1016neq/cm2 were characterized using Transient Current Technique (TCT) measurements with red and infra-red laser pulses. Leakage current variations observed in different production lots and within wafers were investigated using Thermally Stimulated Current (TSC). Results showed that the intrinsic charge amplification is reduced with increasing fluence up to 1015neq/cm2 which is related to an effective acceptor removal. Further relevant issues were charge collection homogeneity across the detector surface and leakage current performance before and after irradiation.
Abstract
Low Gain Avalanche Detectors (LGADs) are n-on-p silicon sensors with an extra p-layer below the collection electrode which provides signal amplification. When the primary electrons reach the ...amplification region new electron-hole pairs are created that enhance the generated signal. The moderate gain of these sensors, together with the relatively thin active region, provide precise time information for minimum ionizing particles. To mitigate the effect of pile-up at the HL-LHC the ATLAS and CMS experiments have chosen the LGAD technology for the High Granularity Timing Detector (HGTD) and for the End-Cap Timing Layer (ETL), respectively. A full characterization of recent productions of LGAD sensors fabricated at CNM has been carried out before and after neutron irradiation up to 2.5 × 10
15
n
eq
/cm
2
. Boron-doped sensors produced in epitaxial and Si-on-Si wafers have been studied. The results include their electrically characterization (IV and bias voltage stability) and performance studies (charge and time resolution) for single pad devices with a Sr-90 radioactive source set-up. The behaviour of the Inter-Pad region for irradiated 2 × 2 LGAD arrays, using the Transient Current Technique (TCT), is shown. The results indicate that the Si-on-Si devices with higher resistivity perform better than the epitaxial ones.
A systematic study of BNL's 3D-Trench Electrode detectors Montalbano, A; Bassignana, D; Li, Z ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2014, Letnik:
765
Journal Article
Recenzirano
New types of silicon pixel detectors have been proposed because of the need for more radiation hard semiconductor devices for the high luminosity tracking detector upgrades at the Large Hadron ...Collider. A novel type of 3D Si pixel detectors is proposed, with each cell of the 3D-Trench Electrode pixel detector featuring a concentric trench electrode surrounding the central collecting column electrode. The pixel sensor is an array of those individual cells. Systematic 3D simulations using Silvacos TCAD programs have been carried out to study the characteristics of this novel 3D pixel design and to compare to the traditional 3D column electrode pixel design. The 3D simulations show a much lower depletion voltage and a more uniform electric field in the new 3D-Trench Electrode pixel detectors as compared to the traditional 3D column Electrode detectors. The first prototype 3D-Trench Electrode pixel detectors have been manufactured at the Centro Nacional De Microelectronica. Preliminary electrical measurements are discussed and charge collection efficiency measurements are presented.
Linear arrays of noble metal nanoparticles, supporting Bragg plasmonic resonances, are proposed as optical nanoantennae. Electrodynamic calculations show that tunable, directional and wavelength ...selective emission enhancement is obtained throughout the visible and near-infrared spectrum by varying the dielectric environment and the array geometrical parameters, and thus tuning the Bragg modes. Large quantum efficiency enhancements are possible even in the case of poor emitters (1% intrinsic efficiency), spanning wavelengths that are relevant in lighting (lambda approximately equal 400 nm) and telecommunication (lambda approximately equal 1.5 microm) applications. Nanoantenna array angular emission is highly directional and extremely sensitive to the array geometrical parameters and the dielectric environment.
Abstract
Collider experiments as the upcoming Phase II-LHC or the future circular collider (FCC) will increase the demands on tracking detectors. In the FCC hadron collider, sensors will not only ...face fluences up to 1 × 10
17
n
eq
/cm
2
, but also high pile-up scenarios. Therefore, sensors will be required not only to have a good spatial resolution and a very high radiation hardness, but also an excellent time resolution of the order of 5 ps. Currently, Low Gain Avalanche Diodes (LGADs) are one of the main candidates when it comes to timing, achieving a resolution well below 30 ps. However, their radiation hardness is not sufficient for future colliders. 3D sensors are an interesting alternative due to their superior radiation hardness. In 3D sensors, which already have been thoroughly investigated for tracking purposes, the drift distances are short, the depletion voltage is very low and the electric field can be very high, thus the signals are fast and short.
In this study, the time resolution of different 3D sensors was investigated with signals generated by MIP-like electrons, as well as by measurements using a laser with an infrared wavelength. It is shown that 3D pixel sensors can achieve time resolutions competitive with those of LGADs. Additionally, Transient Current Technique (TCT) timing measurements have been conducted. These allow to study the position dependence of the time resolution, which is interesting for 3D sensors due to their complex electric field structure. The measurements prove the direct correlation between the time resolution and the electric field configuration. Furthermore, the performance of the sensors is demonstrated before and after irradiation with reactor neutrons.
Sensors for ultra-fast silicon detectors Sadrozinski, H.F.-W.; Baselga, M.; Ely, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2014, Letnik:
765
Journal Article
Recenzirano
We report on electrical and charge collection tests of silicon sensors with internal gain as part of our development of ultra-fast silicon detectors. Using C–V and α TCT measurements, we investigate ...the non-uniform doping profile of so-called low-gain avalanche detectors (LGAD). These are n-on-p pad sensors with charge multiplication due to the presence of a thin, low-resistivity diffusion layer below the junction, obtained with a highly doped implant. We compare the bias dependence of the pulse shapes of traditional sensors and of LGAD sensors with different dopant density of the diffusion layer, and extract the internal gain.
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