Active vibration isolation system for CLIC final focus

International audienceWith pinpoint accuracy, the next generation of Linear Collider such as CLIC will collide electron and positron beams at a centre of mass energy of 3 TeV with a desired peak luminosity of 2*1034 cm-2s-1. One of the many challenging features of CLIC is its ability to collide beams at the sub-nanometer scale at the Interaction Point (IP). Such a high level of accuracy could only be achieved by integrating Active Vibration Isolation systems (AVI) upstream of the collision to prevent the main source of vibration: Ground Motion (GM). Complementary control systems downstream of the collision (Interaction Point FeedBack (IPFB), Orbit FeedBack (OFB)) allow low frequency vibration rejection. This paper focuses on a dedicated AVI table designed for the last focusing quadrupole (QD0) where the specifications are the most stringent. Combining FeedForward (FF) and FeedBack (FB) techniques, the prototype is able to reduce GM down to 0.6 nm RMS(4Hz) experimentally without any load. These performances couldn't be achieved without cutting edge-technology such as sub-nanometer piezo actuators, ultra-low noise accelerometers and seismometers and an accurate guidance system. The whole AVI system is described in details. Further developments concern the integration of the final focusing magnet above the AVI table, first as part of the simulation with its dynamical model, and finally, as a realistic prototype

Dibasic cleavage site is required for sorting to the regulated secretory pathway for both pro- and neuropeptide Y

To investigate the signals governing routing of biologically active peptides to the regulated secretory pathway, we have expressed mutated and non-mutated proneuropeptide Y (ProNPY) in pituitary-derived AtT20 cells. The mutations were carried out on dibasic cleavage site and or ProNPY C-terminal sequence. Targeting to the regulated secretory pathway was studied using protein kinase A (8-BrcAMP), protein kinase C (phorbol myristate acetate) specific activators and protein synthesis inhibitor cycloheximide, and by pulse chase. The analysis of expressed peptides in cells and culture media indicated that: neuropeptide Y (NPY) and ProNPY were differently secreted, whilst NPY was exclusively secreted via regulatory pathway; ProNPY was secreted via regulated and constitutive-like secretory pathways. ProNPY secretion behaviour was not Proteolytic cleavage efficiency-dependent. The dibasic cleavage was essential for ProNPY and NPY cAMP-dependent regulated secretion and may have function as a retention signal

The STEREO experiment

International audienceThe STEREO experiment is a very short baseline reactor antineutrino experiment aiming at testing the hypothesis of light sterile neutrinos as an explanation of the deficit of the observed neutrino interaction rate with respect to the predicted rate, known as the Reactor Antineutrino Anomaly. The detector center is located 10 m away from the compact, highly 235U enriched core of the research nuclear reactor of the Institut Laue Langevin in Grenoble, France. This paper describes the STEREO site, the detector components and associated shielding designed to suppress the external sources of background which were characterized on site. It reports the performances in terms of detector response and energy reconstruction

The STEREO experiment

The STEREO experiment is a very short baseline reactor antineutrino experiment aiming at testing the hypothesis of light sterile neutrinos as an explanation of the deficit of the observed neutrino interaction rate with respect to the predicted rate, known as the Reactor Antineutrino Anomaly. The detector center is located 10 m away from the compact, highly 235U enriched core of the research nuclear reactor of the Institut Laue Langevin in Grenoble, France. This paper describes the STEREO site, the detector components and associated shielding designed to suppress the external sources of background which were characterized on site. It reports the performances in terms of detector response and energy reconstruction