41 research outputs found
Analysis of test beam data taken with a prototype of TPC with resistive Micromegas for the T2K Near Detector upgrade
In this paper we describe the performance of a prototype of the High Angle
Time Projection Chambers (HA-TPCs) that are being produced for the Near
Detector (ND280) upgrade of the T2K experiment. The two HA-TPCs of ND280 will
be instrumented with eight Encapsulated Resistive Anode Micromegas (ERAM) on
each endplate, thus constituting in total 32 ERAMs. This innovative technique
allows the detection of the charge emitted by ionization electrons over several
pads, improving the determination of the track position. The TPC prototype has
been equipped with the first ERAM module produced for T2K and with the HA-TPC
readout electronics chain and it has been exposed to the DESY Test Beam in
order to measure spatial and dE/dx resolution. In this paper we characterize
the performances of the ERAM and, for the first time, we compare them with a
newly developed simulation of the detector response. Spatial resolution better
than 800 and dE/dx resolution better than 10% are observed for
all the incident angles and for all the drift distances of interest. All the
main features of the data are correctly reproduced by the simulation and these
performances fully fulfill the requirements for the HA-TPCs of T2K
Characterization of Charge Spreading and Gain of Encapsulated Resistive Micromegas Detectors for the Upgrade of the T2K Near Detector Time Projection Chambers
An upgrade of the near detector of the T2K long baseline neutrino oscillation
experiment is currently being conducted. This upgrade will include two new Time
Projection Chambers, each equipped with 16 charge readout resistive Micromegas
modules. A procedure to validate the performance of the detectors at different
stages of production has been developed and implemented to ensure a proper and
reliable operation of the detectors once installed. A dedicated X-ray test
bench is used to characterize the detectors by scanning each pad individually
and to precisely measure the uniformity of the gain and the deposited energy
resolution over the pad plane. An energy resolution of about 10% is obtained. A
detailed physical model has been developed to describe the charge dispersion
phenomena in the resistive Micromegas anode. The detailed physical description
includes initial ionization, electron drift, diffusion effects and the readout
electronics effects. The model provides an excellent characterization of the
charge spreading of the experimental measurements and allowed the simultaneous
extraction of gain and RC information of the modules
Development of a thin flexible Li battery design with a new gel polymer electrolyte operating at room temperature
In this study, we develop a new Li-metal battery design merging with IoT requirements, mainly the low thickness, the thermal stability and the flexibility. To reach these specifications, we firstly prepared an efficient gel polymer electrolyte (GPE) composed of a PVDF-HFP polymer network, a LiFSI: Pyr13FSI liquid binary solution and a lithium montmorillonite Li-MMT clay. The as-synthesized material exhibits a high ionic conductivity (0.48 mS cm-1 at 25 âŠC) and a good thermal stability, up to 140 âŠC. In parallel, a new battery design with an optimized ratio of packaging to active material thickness is developed. In this design, copper foils act both as current collector and as battery casing, decreasing the overall cell thickness. Li metal batteries are realized using the developed GPE material and this new battery design. The cell thickness is 360 and 760 ÎŒm for single side and double-sided architectures respectively. These batteries show well functioning under high bending and exhibit a good cycling ability with a remaining capacity higher than 85% after more than 200 cycles at 25 âŠC. Thanks to the combination of the original Cu packaging and the flexible GPE membrane, developed Li-metal batteries exhibit promising properties to merge with the new IoT requirements.EnSO projec
Li conductivity in Li1+xTi2-xAlx(PO4)3 (0.3†x†0.7) ceramics prepared from sol-gel precursors
Rechargeable ThinâFilm Lithium Microbattery Using a QuasiâSolidâState Polymer Electrolyte
International audienceAbstract A thinâfilm microbattery was designed after synthesizing a unique gel polymer electrolyte (GPE), using polyvinylidene fluorideâcoâhexafluoropropylene (PVdFâHFP) and crossâlinked poly(ethylene oxide) (PEO), with an ionic liquid and salt (LiTFSI) mixture. The polymers resulted in a semiâinterpenetrated polymer network (semiâIPN), hosting an ionic liquid (IL)/salt mixture, and thus exhibited high ionic conductivity and excellent mechanical properties. Nuclear magnetic resonance (NMR) diffusion measurements and relaxation rates analysis highlighted the existence of interactions between Li + ions and oxygen within the polymers, preventing electrolyte leakage and ensuring excellent mechanical strength which enabled a unique quasiâsolid electrolyte. Such mechanical strength and chemical stability made this electrolyte to be first ever reported GPE to withstand thermal evaporation deposition and hence direct deposition of lithium metal. The electrolyte could be shaped as selfâstanding thin films, and thus worked as both separator and electrolyte in a thinâfilm lithium microbattery. The thinâfilm microbattery exhibited excellent performances showing no shortâcircuit current, an open circuit voltage of âŒ3.0â
V, higher nominal voltage plateau, lower equivalent series resistance by comparison to a thinâfilm microbattery designed in conventional way with a popular ceramic electrolyte LiPON