Boosting the performance of the ASTRI SST-2M prototype: reflective and anti-reflective coatings

ASTRI is a Flagship Project of the Italian Ministry of Education, University and Research, led by the Italian National Institute of Astrophysics, INAF. One of the main aims of the ASTRI Project is the design, construction and verification on-field of a dual mirror (2M) end-to-end prototype for the Small Size Telescope (SST) envisaged to become part of the Cherenkov Telescope Array. The ASTRI SST-2M prototype adopts the Schwarzschild-Couder design, and a camera based on SiPM (Silicon Photo Multiplier); it will be assembled at the INAF astronomical site of Serra La Nave on mount Etna (Catania, Italy) within mid 2014, and will start scientific validation phase soon after. The peculiarities of the optical design and of the SiPM bandpass pushed towards specifically optimized choices in terms of reflective coatings for both the primary and the secondary mirror. In particular, multi-layer dielectric coatings, capable of filtering out the large Night Sky Background contamination at wavelengths $\lambda \gtrsim 700$ nm have been developed and tested, as a solution for the primary mirrors. Due to the conformation of the ASTRI SST-2M camera, a reimaging system based on thin pyramidal light guides could be optionally integrated aiming to increase the fill factor. An anti-reflective coating optimized for a wide range of incident angles faraway from normality was specifically developed to enhance the UV-optical transparency of these elements. The issues, strategy, simulations and experimental results are thoroughly presented.Comment: 4 pages, 6 figures. In Proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), Rio de Janeiro (Brazil). All ASTRI contributions at arXiv:1307.463

Current Drop Noise in RCA 23 FEM

This document has been issued in the frame of ASI contract that has been released for the activities of Planck-LFI Phase E2 Scope of this document is to give a description of a feature observed during PLM SIT test on RCA 23, this description could be used to open a dedicated NCR in order to monitor the problem through the System Test Campaign. The data shown here after have been collected during the PLM SIT performed on the 24th of October 2007 in Cannes

Tuning strategy for CSL

This Note shows the strategy to proposed to tune the LFI LNA’s (Vg1 & Vg2) in the test campaign at Satellite Level to be performed in CSL (Centre Spatiale de Liege) during the next Summer 2008 . The baseline option was accepted to be the MATRIX scheme , mixing together Vg1 and Vg2 values. The main limit to this method is given ( in CSL ) by the time required to explore a large range of parameters, since in CSL it is limited and strictly related with the 4K cooler cooldown profile. This note wants to give an overview of the philosophy and possible advantages or limits related with one or another strategy

Analysis of the thermal behaviour of the LFI-RAA cryogenic chamber in ALS

The scope of this document is to present a thermal analysis of the RAA Cryofacility used in the LFI QM Test in ALS . The data used for this analysis cover 8 days of testing: from the 18th to the 25th of July 2005. The aim of the analysis is to understand the behaviour of the LFI RAA cryogenic chamber and to provide useful indications to fully exploit the cryochamber thermal data during the instrument calibration data analysi

Analysis of Signal Swap in output of Channel 2510 (Action#4 H-PTASF- MN-9737)

Scope of this document is to provide a description of an unexpected feature observed on RCA 25 during EMC Conducted test., During data analysis was found that the same behaviour was present in SFT data and in PLM SIT test data. This description shall be used to update the dedicated NCR, in order to monitor the problem through the System Test Campaign. The data shown here after have been collected during the EMC Conducted performed on 2nd October (AMB_108) PLM SIT performed on the 24th of October 2007 (AMB_0114) in Cannes and from the SFT performed 18th September (AMB_0099)

In-flight calibration and verification of the Planck-LFI instrument

In this paper we discuss the Planck-LFI in-flight calibration campaign. After a brief overview of the ground test campaigns, we describe in detail the calibration and performance verification (CPV) phase, carried out in space during and just after the cool-down of LFI. We discuss in detail the functionality verification, the tuning of the front-end and warm electronics, the preliminary performance assessment and the thermal susceptibility tests. The logic, sequence, goals and results of the in-flight tests are discussed. All the calibration activities were successfully carried out and the instrument response was comparable to the one observed on ground. For some channels the in-flight tuning activity allowed us to improve significantly the noise performance.Comment: Long technical paper on Planck LFI in flight calibration campaign: 109 pages in this (not final) version, 100 page in the final JINST versio

Proposal for LFI test dedicated to characterize New Spikes in the FFT spectrum of Scientific Data

This document has been issued in the frame of ASI contract that has been released for the activities of Planck-LFI Phase E2 Scope of this document is to give a description of a new and unexpected feature found during the warm tests at system level in the LFI FFT spectrum of the scientific data. The scope of the document is two folds - Describe the feature so to open a dedicated NCR - Describe a proposal of a dedicated test in order to characterize the featur