Search results for " SNR"

Hydrodynamic modelling of ejecta shrapnel in the Vela supernova remnant

2013

Many supernova remnants (SNRs) are characterized by a knotty ejecta structure. The Vela SNR is an excellent example of remnant in which detached clumps of ejecta are visible as X-ray emitting bullets that have been observed and studied in great detail. We aim at modelling the evolution of ejecta shrapnel in the Vela SNR, investigating the role of their initial parameters (position and density) and addressing the effects of thermal conduction and radiative losses. We performed a set of 2-D hydrodynamic simulations describing the evolution of a density inhomogeneity in the ejecta profile. We explored different initial setups. We found that the final position of the shrapnel is very sensitive …

A High-resolution Survey of the physical and chemical Inhomogeneities in the Vela SNR

2007

Signal to Noise Ratio of Silicon Photomultipliers: a study in the Continuous Wave Regime

2014

We report on Signal to Noise Ratio measurements carried out, in the continuous wave regime, at different bias voltages, frequencies and temperatures, on a novel class of silicon photomultipliers fabricated in planar technology on silicon p-type substrate. Signal to Noise Ratio has been measured as the ratio of the photogenerated current, filtered and averaged by a lock-in amplifier, and the Root Mean Square deviation of the same current. The measured noise takes into account the shot noise, resulting from the photocurrent and the dark current. We have also performed a comparison between our SiPMs and a photomultiplier tube in terms of Signal to Noise Ratio, as a function of the temperature …

Indications of a Si-rich bilateral jet of ejecta in the Vela SNR observed with XMM-Newton

2017

Context. The Vela supernova remnant displays several ejecta, which are fragment-like features protruding beyond the front of its primary blast shock wave. They appear to be "shrapnel", bowshock-shaped relics of the supernova explosion. One of these pieces of shrapnel (A), located in the northeastern edge of the remnant, is peculiar because its X-ray spectrum exhibits a high Si abundance, in contrast to the other observed ejecta fragments, which show enhanced O, Ne, and Mg abundances. Aims. In this Letter we present the analysis of another ejecta fragment located opposite to shrapnel A with respect to the center of the shell, in the southwestern boundary of the remnant, named shrapnel G. We …

Shock-cloud interaction in the Vela SNR: the XMM-Newton view

2004

ABA-independent SnRK2 kinases are involved in plant response to salinity

2013

Un poster a été présenté lors de cet événement SPE IPM CT non renseigné car non soutenu par INRA; International audience; Sucrose non-fermenting 1-Related Protein Kinases type 2 family (known as SnRK2) are important group of kina- ses present in all tested plant species. It is known that all SnRK2 (excluding SnRK2.9) are activated in response to salinity and hyperosmolarity in Arabidopsis thaliana protoplasts after short time of treatment. In plants, they are in- volved in the early responses to drought and salinity. Recently published data indicate that SnRK2.4 plays important role in the maintenance of root system architecture during salt stress and in response to cadmium treatment. It wa…

Trans-cranial Magnetic Resonance-guided Focused UltraSound (tcMRgFUS) system integrated with a 1.5T: an SNR study on DQA phantoms

2018

Background: In recent years transcranial Magnetic Resonance-guided Focused Ultrasound Surgery (tcMRgFUS) treatments have been performed only using 3T units. Since following some internal analysis, planning images obtained using a 1.5T MRI’s body RF coil (as usually done with 3T systems) showed generally reasonable quality in terms of anatomy visualization and SNR but thermal images noise was above acceptable standard for treatments, a dedicated 2-channels head coil was developed (InSightec Ltd.) to ensure an adequate signal-to-noise ratio (SNR). Hence, we present the imaging protocol and the technological methods successfully used with the world-first installation of a certified tcMRgFUS sy…

Hydrodynamic simulations of the shock-cloud interaction in the Vela supernova remnant

2005

Signal to noise ratio measurements of silicon photomultipliers in the continuous wave regime

2014

We report on our signal to noise ratio (SNR) measurements carried out, in the continuous wave regime, on a novel class of silicon photomultipliers (SiPMs) fabricated in planar technology on silicon p-type substrate.

Signal to noise ratio measurements of silicon photomultipliers

2014

We report on our signal to noise ratio (SNR) measurements carried out, in the continuous wave regime, on a novel class of silicon photomultipliers (SiPMs) fabricated in planar technology on silicon p-type substrate. SiPMs are large area detectors consisting of a parallel array of Geiger Mode APDs with individual integrated quenching resistors. Each photodiode is an independent photon counting microcell and is connected to a common analog output to produce a summation signal proportional to the number of detected photons [1], [2]. SNR of SiPMs is expressed by the ratio of the SiPM average signal current and the RMS deviation of the overall current (i.e., the overall shot noise current). The …