Search Results (9)

The purpose of this study was to test the microhardness and compressive strength of mineral trioxide aggregate (MTA) modified by the addition of short glass fibers (SGFs) and shredded polyglycolic acid (PGA) sutures. Encapsulated MTA (MM-MTA, MicroMega, Besançon, France), modified using either SGF or shredded PGA sutures, was used for the experiment. Four experimental groups (n = 120) were as follows: control group (MTA) (n = 30), MM MTA + 5%SGF (n = 30), MM MTA + 10%SGF (n = 30), and MM MTA + 1%PGA (n = 30). For the modified materials, MM MTA powder was removed from the capsule by 1%, 5% and 10% of weight and 1% PGA, 5%, or 10% SGF were added, respectively. The microhardness of the samples (n = 20 per group) was measured using a Vickers microhardness testing machine, while compressive strength (n = 10 per group) was measured according to ISO 9917-1:2007. The highest microhardness value was measured for MTA + 10%SGF (14.73 ± 3.09) with a statistically significant difference in comparison to the other three groups (p < 0.05). Statistically significant higher compressive strength was measured in the groups with the addition of 5% and 10% SGF compared to MM MTA (p = 0.047 for both comparisons). There were no statistically significant differences between the groups (p = 0.784) regarding the compressive modulus. The addition of SGF significantly increased both the microhardness and compressive strength of MM MTA. Full article

The High-Luminosity Large Hadron Collider (HL-LHC) project aims to improve the performance of the LHC by increasing the proton–proton collision luminosity. New physics discoveries will be possible starting in 2027. The HL-LHC aims to improve the integrated luminosity by a factor of 10 concerning the current running LHC’s design value. The HL-LHC project foresees delivering proton–proton collisions at 14 TeV CM (Center of Mass) energy providing the integrated luminosity to a value of 3 ab⁻¹ for the ATLAS and CMS experiments, 50 fb⁻¹ for LHCb, and 5 fb⁻¹ for ALICE. The increased integrated luminosity for the above LHC experiments will provide the potential to discover rare processes while improving these measurements’ signal-to-noise (S/N) ratio statistics. The ATLAS muon spectrometer has been upgraded to face the challenges of the luminosity at the HL-LHC run. The new sub-detectors are as follows: The New Small Wheel (NSW) has replaced the Cathode Strip Chambers (CSC) discs at the internal part of the ATLAS end cups. The new integrated small Monitored Drift Chambers (sMDT) with the Resistive Plate Chambers (RPC) are installed at the outer end of the ATLAS BI (Barrel Inner) layer, in the barrel–endcap transition region, at 1.0 < |η| < 1.3, where η is the pseudo-rapidity (pseudo-rapidity η is a commonly used spatial coordinate describing the angle of a particle relative to the beam axis, defined as $\eta =-ln\left[tan\left({\displaystyle \frac{\theta }{2}}\right)\right]$, where θ is the angle between the vector momentum $\overrightarrow{p}$ and the positive direction of the beam axis). The NSW is an innovative technological achievement, including the MicroMegas (MM) gas detectors in large areas and small-strip Thin Gap Chambers (sTGC), enabling high p_T (high p_T is the high value of the particles’ transverse momentum versus the beam collision axis) trigger and muon detection. The muon reconstruction, the background rate, other spectrometer parameters, and the NSW performance are also presented. Full article

The High-Angle Time Projection Chambers (HA-TPCs) are a new set of detectors that will equip the off-axis near detector (ND280) of the T2K long-baseline neutrino oscillation experiment. A prototype of the Field Cage instrumented with one ERAM detector has been recently exposed to a DESY electron beam. In order to ensure that the HA-TPCs satisfy the required performances for the ND280 Upgrade (space point resolution better than 600 µm and dE/dx resolution smaller than 10%), the ERAM detectors have been characterized with X-ray sources and by exposing them to the DESY electron beam. In addition, a detailed simulation of the charge spreading phenomenon and of the electronic response is reported. Full article

We compared the mechanical properties of 2Shape mini TS2 (Micro-Mega, Besançon, France) obtained from 1.0 diameter nickel-titanium (NiTi) wires and 2Shape TS2 from 1.2 diameter nickel-titanium (NiTi) wires differently thermally treated at room and body temperature. We used 120 NiTi TS2 1.0 and TS2 1.2 files made from controlled memory (CM) wire and T-wire (n = 10). Cyclic fatigue resistance was tested by recording the number of cycles to fracture (NCF) at room and body temperatures using a customized testing device. Maximum torque and angle of rotation at failure were recorded, according to ISO 3630-1. Data were analyzed by a two-way ANOVA (p < 0.05). The CM-wire files had significantly higher NCFs at both temperatures, independent of wire dimensions. Testing at body temperature negatively affected cyclic fatigue of all files. The 1.0-mm diameter T-wire instruments showed higher NCF than the 1.2-mm diameter, whereas no significant differences emerged between the two CM wires at either temperature. The maximum torque was not significantly different across files. The TS2 CM-wire files showed significantly higher angular rotation to fracture than T-wire files. The TS2 CM-wire prototypes showed higher cyclic fatigue resistance than T-wire prototypes, regardless of wire size, exhibiting suitable torsional properties. Torsional behavior appears to not be affected by NiTi wire size. Full article

Tomography based on cosmic muon absorption is a rising technique because of its versatility and its consolidation as a geophysics tool over the past decade. It allows us to address major societal issues such as long-term stability of natural and man-made large infrastructures or sustainable underwater management. Traditionally, muon trackers consist of hodoscopes or multilayer detectors. For applications with challenging available volumes or the wide field of view required, a thin time projection chamber (TPC) associated with a Micromegas readout plane can provide a good tradeoff between compactness and performance. This paper details the design of such a TPC aiming at maximizing primary signal and minimizing track reconstruction artifacts. The results of the measurements performed during a case study addressing the aforementioned applications are discussed. The current works lines and perspectives of the project are also presented. Full article

Micromegas (MICRO-MEsh GAseous Structure) detectors have found common use in different applications since their development in 1996 by the group of I. Giomataris and G. Charpak. In this review article, we present implementations of Micromegas sub-detectors in different physics experiments and highlight the current state of development for innovative detection concepts with Micromegas. Full article

In this article, we present a system to measure current in the range of 0 to 10 $\mathsf{\mu }$A with high-voltage isolation up to 5 kV. This current monitor consists of three ammeters connected in series, to improve the resolution in the measurement. The design features several innovative elements such as using low voltage to provide power to the devices to measure the current and digitize it with a sampling frequency of 1 KHz, it is generated based on a DC-DC converter that produces three voltages, +12 V, −12 V, and 5 V, from a conventional 10 V source. The three voltages are referenced to the same floating ground. The DC-DC converter has a high voltage insulation up to 5 kV and four optocouplers with an insulation up to 20 kV are used to read the digitized data. The introduction of a DC-DC converter contributed to reduce the noise level in the analog part of the circuit which has been resolved implementing shields inside the board. In particle physics, several systems are used to detect particles in high-energy physics experiments such as Gas Electron Multiplier (GEM), micromegas, etc. GEMs suffer small deteriorations due to discharges in constant operation and require monitoring the current consumption at high frequency (1 kHz). In this work, we present the design and operation of a 0 to 10 $\mathsf{\mu }$A auto scale ammeter. The results obtained by monitoring the current in a 10 × 10 cm${}^2$ GEM are shown. Full article

Due to the so-called ³He shortage crisis, many detection techniques for thermal neutrons are currently based on alternative converters. There are several possible ways of increasing the detection efficiency for thermal neutrons using the solid neutron-to-charge converters ¹⁰B or ¹⁰B₄C. Here, we present an investigation of the Micromegas technology. The micro-pattern gaseous detector Micromegas was developed in the past years at Saclay and is now used in a wide variety of neutron experiments due to its combination of high accuracy, high rate capability, excellent timing properties, and robustness. A large high-efficiency Micromegas-based neutron detector is proposed for thermal neutron detection, containing several layers of ¹⁰B₄C coatings that are mounted inside the gas volume. The principle and the fabrication of a single detector unit prototype with overall dimension of ~15 × 15 cm² and its possibility to modify the number of ¹⁰B₄C neutron converter layers are described. We also report results from measurements that are verified by simulations, demonstrating that typically five ¹⁰B₄C layers of 1–2 μm thickness would lead to a detection efficiency of 20% for thermal neutrons and a spatial resolution of sub-mm. The high potential of this novel technique is given by the design being easily adapted to large sizes by constructing a mosaic of several such detector units, resulting in a large area coverage and high detection efficiencies. An alternative way of achieving this is to use a multi-layered Micromegas that is equipped with two-side ¹⁰B₄C-coated gas electron multiplier (GEM)-type meshes, resulting in a robust and large surface detector. Another innovative and very promising concept for cost-effective, high-efficiency, large-scale neutron detectors is by stacking ¹⁰B₄C-coated microbulk Micromegas. A prototype was designed and built, and the tests so far look very encouraging. Full article

Several recent detector technologies developed for particle physics applications are based on microfabricated structures. Detectors built with this approach generally exhibit the overall best performance in terms of spatial and time resolution. Many properties of the SU-8 photoepoxy make it suitable for the manufacturing of microstructured particle detectors. This article aims to review some emerging detector technologies making use of SU-8 microstructuring, namely micropattern gaseous detectors and microfluidic scintillation detectors. The general working principle and main process steps for the fabrication of each device are reported, with a focus on the advantages brought to the device functionality by the use of SU-8. A novel process based on multiple bonding steps for the fabrication of thin multilayer microfluidic scintillation detectors developed by the authors is presented. Finally, a brief overview of the applications for the discussed devices is given. Full article