Rad-hard vertical JFET switch for the HV-MUX system of the ATLAS upgrade Inner Tracker

This work presents a new silicon vertical JFET (V-JFET) device, based on the trenched 3D-detector technology developed at IMB-CNM, to be used as switches for the High-Voltage powering scheme of the ATLAS upgrade Inner Tracker. The optimization of the device characteristics is performed by 2D and 3D TCAD simulations. Special attention has been paid to the on-resistance and the switch-off and breakdown voltages to meet the specific requirements of the system. In addition, a set of parameter values has been extracted from the simulated curves to implement a SPICE model of the proposed V-JFET transistor. As these devices are expected to operate under very high radiation conditions during the whole experiment life-time, a study of the radiation damage effects and the expected degradation on the device performance is also presented at the end of the paper.Comment: KEYWORDS: Radiation-hard electronics; Voltage distributions; Large detector systems for particle and astroparticle physics. 9 Pages, 7 Figure

Proximity effect in planar Superconductor/Semiconductor junction

We have measured the very low temperature (down to 30 mK) subgap resistance of Titanium Nitride (Superconductor, Tc = 4.6 K)/highly doped Silicon (Semiconductor) SIN junction (the insulating layer stands for the Schottky barrier). As the temperature is lowered, the resistance increases as expected in SIN junction. Around 300 mK, the resistance shows a maximum and decreases at lower temperature. This observed behavior is due to coherent backscattering towards the interface by disorder in Silicon ("Reflectionless tunneling"). This effect is also observed in the voltage dependence of the resistance (Zero Bias Anomaly) at low temperature (T<300 mK). The overall resistance behavior (in both its temperature and voltage dependence) is compared to existing theories and values for the depairing rate, the barrier resistance and the effective carrier temperature are extracted.Comment: Submitted to LT22, Helsinki - August 1999, phbauth.cls include

Ultra-thin 3D silicon sensors for neutron detection

We present a novel neutron detector based on an ultra-thin 3D silicon sensor with a sensitive volume only 10 µm thick. This ultra-thin active volume allows a high gamma-ray rejection, a key requirement in order to discriminate the signal coming from the neutrons in a mixed neutron-gamma ray environment. The device upper-side is covered with a novel boron-based compound that detects neutrons by means of the 10B(n,α)7Li nuclear reaction. The performance of test devices has been investigated first with a gamma-ray source to evaluate the gamma-ray rejection factor, and then with an 241AmBe neutron source to assess the neutron-gamma ray discrimination properties.Peer reviewe

Thermal and hydrodynamic studies for micro-channel cooling for large area silicon sensors in high energy physics experiments

Micro-channel cooling initially aiming at small-sized high-power integrated circuits is being transferred to the field of high energy physics. Today`s prospects of micro-fabricating silicon opens a door to a more direct cooling of detector modules. The challenge in high energy physics is to save material in the detector construction and to cool large areas. In this paper, we are investigating micro-channel cooling as a candidate for a future cooling system for silicon detectors in a generic research and development approach. The work presented in this paper includes the production and the hydrodynamic and thermal testing of a micro-channel equipped prototype optimized to achieve a homogeneous flow distribution. Furthermore, the device was simulated using finite element methods.Comment: 10 pages, submitted to NIMA (accepted

Ultra Thin 3D Silicon Detector for Plasma Diagnostics at the ITER Tokamak

An ultra thin silicon detector called U3DTHIN[1,2] has been designed and built to be used in detection systems for Neutral particle analyzers (NPA). The main purpose of this detector is to provide a state-of-the-art solution for NPAs at ITER experimental reactor. In the past the NPAs were using very thin scintillators read out by photomultiplier tubes[3,4], and their main drawbacks were poor energy resolution, intrinsic scintillation non-linearity, relative low count rate capability and finally poor signal-to-background separation for the low energy channels. The proposed U3DTHIN detector is based on very thin sensitive substrate which will provide nearly 100% detection efficiency for ions and at the same time very low sensitivity for the neutron and gamma radiation background. To achieve a very fast charge collection of the carriers generated by the ions a 3D electrode structure[5] has been introduced in the sensitive volume of the detector. One of the most innovative features of these detectors has been the optimal combination of the thin entrance window and the sensitive substrate thickness, to accommodate very large dynamic range primary ions energy. With an entrance window of tens of nanometers; together with a sensitive substrate thickness of less than 5 μm we used them for the low energetic channels and lest than 20 μm for the medium and high energetic ones. In order to find the optimal Signal to background ratio simulations with GEANT4 and TCAD has been performed. The first results obtained during characterization of such U3DTHIN detectors will be presented.Non peer reviewe

Low gain avalanche detectors for high energy physics experiments

Trabajo presentado a la 10th Spanish Conference on Electron Devices, celebrada en Aranjuez (Madrid, España) del 11 al 13 de febrero de 2015.This paper describes a new concept of Silicon radiation detector with internal multiplication of the charge generated by the incident particle, known as Low Gain Avalanche Detector (LGAD), with a gain in the range of 10-20. The LGAD is addressed to tracking applications for high energy physics with enhanced performances compared to the conventional detectors based on the PiN diode structure. The physical behavior, the critical design challenges and the first experimental data on the fabricated LGAD prototypes is described in the paper.Peer Reviewe

Recent technological developments on LGAD and iLGAD detectors for tracking and timing applications

Proceeding of the 10th International “Hiroshima” Symposium on the Development and Application of Semiconductor Tracking Detectors.-- et al.This paper reports the latest technological development on the Low Gain Avalanche Detector (LGAD) and introduces a new architecture of these detectors called inverse-LGAD (iLGAD). Both approaches are based on the standard Avalanche Photo Diodes (APD) concept, commonly used in optical and X-ray detection applications, including an internal multiplication of the charge generated by radiation. The multiplication is inherent to the basic n–p–p structure, where the doping profile of the p layer is optimized to achieve high field and high impact ionization at the junction. The LGAD structures are optimized for applications such as tracking or timing detectors for high energy physics experiments or medical applications where time resolution lower than 30 ps is required. Detailed TCAD device simulations together with the electrical and charge collection measurements are presented through this work.This work was developed in the framework of the CERN RD50 collaboration and financed by the Spanish Ministry of Economy and Competitiveness through the Particle Physics National Program (FPA2013-48308-C2-2-P, FPA2014-55295-C3-2-R and FPA2013-48387-C6-1-P). This project has received funding from the European Union's Horizon 2020 Research and Innovation program under Grant Agreement no. 654168 (AIDA-2020).Open Access funded by CERN.Peer Reviewe

Seismic constraints on rotation of Sun-like star and mass of exoplanet

Rotation is thought to drive cyclic magnetic activity in the Sun and Sun-like stars. Stellar dynamos, however, are poorly understood owing to the scarcity of observations of rotation and magnetic fields in stars. Here, inferences are drawn on the internal rotation of a distant Sun-like star by studying its global modes of oscillation. We report asteroseismic constraints imposed on the rotation rate and the inclination of the spin axis of the Sun-like star HD 52265, a principal target observed by the CoRoT satellite that is known to host a planetary companion. These seismic inferences are remarkably consistent with an independent spectroscopic observation (rotational line broadening) and with the observed rotation period of star spots. Furthermore, asteroseismology constrains the mass of exoplanet HD 52265b. Under the standard assumption that the stellar spin axis and the axis of the planetary orbit coincide, the minimum spectroscopic mass of the planet can be converted into a true mass of 1.85 (+0.52,-0.42) M_Jupiter, which implies that it is a planet, not a brown dwarf.Comment: Published in Proceedings of the National Academy of Sciences (5 pages, 5 figures, 3 tables). Available at http://www.pnas.org/cgi/doi/10.1073/pnas.130329111

Detector de radiación transmisivo

Peer reviewedConsejo Superior de Investigaciones Científicas, Consorcio para la Construcción, Equipamiento y Explotación del Laboratorio de Luz de Sincrotón, Alibava Systems S.L.U Solicitud de modelo de utilida

Kepler-21b: A 1.6REarth Planet Transiting the Bright Oscillating F Subgiant Star HD 179070

We present Kepler observations of the bright (V=8.3), oscillating star HD 179070. The observations show transit-like events which reveal that the star is orbited every 2.8 days by a small, 1.6 R_Earth object. Seismic studies of HD 179070 using short cadence Kepler observations show that HD 179070 has a frequencypower spectrum consistent with solar-like oscillations that are acoustic p-modes. Asteroseismic analysis provides robust values for the mass and radius of HD 179070, 1.34{\pm}0.06 M{\circ} and 1.86{\pm}0.04 R{\circ} respectively, as well as yielding an age of 2.84{\pm}0.34 Gyr for this F5 subgiant. Together with ground-based follow-up observations, analysis of the Kepler light curves and image data, and blend scenario models, we conservatively show at the >99.7% confidence level (3{\sigma}) that the transit event is caused by a 1.64{\pm}0.04 R_Earth exoplanet in a 2.785755{\pm}0.000032 day orbit. The exoplanet is only 0.04 AU away from the star and our spectroscopic observations provide an upper limit to its mass of ~10 M_Earth (2-{\sigma}). HD 179070 is the brightest exoplanet host star yet discovered by Kepler.Comment: Accepted to Ap