Noto Station Status Report

The Noto VLBI station was fully operational in 2012, and the upgrade projects could be restarted, involving mainly the receiver area. Another important improvement was the activation of the 1 Gbps network

A digital beamformer for the PHAROS2 phased array feed

PHased Arrays for Re°ector Observing Systems (PHAROS) is a C-band (4–8 GHz) Phased Array Feed (PAF) receiver designed to operate from the primary focus of a large single-dish radio astronomy antenna. It consists of an array of 220-element Vivaldi antennas (10 11 2 polarization), cryogenically cooled at roughly 20K along with low noise ampli¯ers (LNAs), and of analogue beamformers cryogenically cooled at roughly 80 K. PHAROS2, the upgrade of PHAROS, is a PAF demonstrator developed in the framework of the Square Kilometer Array Advanced Instrumentation Program (SKA AIP) with the goal of investigating the potential of the PAF technologies at high frequencies in view of their possible application on the SKA dish telescopes. The PHAROS2 design includes new cryogenically cooled LNAs with state-of-the-art performance, a digital beamformer capable of synthesizing four beams from a sub-array of 24 single-polarization antenna elements, and a C-band multi-channel Warm Section receiver capable of analogue ¯ltering and down-converting the signals from the antennas to a suitable frequency range at the input of the digital backend, providing an instantaneous bandwidth of 275MHz for each signal. In this paper, we describe the design and performance of the PHAROS2 digital backend/beamformer, based on the Italian Tile Processing Module (ITPM) hardware, which was initially developed for the SKA Low Frequency Aperture Array (LFAA). The backend was adapted to perform the beamforming for our PAF application. We describe the implementation of the beamformer on the Field Programmable Gate Arrays (FPGAs) of the ITPM and how the backend was successfully used to synthesize four independent beams, both in the laboratory (across the entire 275MHz instantaneous bandwidth) and during on-¯eld observations at the BEST-2 array (across 16MHz instantaneous bandwidth), which is a subset of the Northern Cross Radio Telescope (located in the district of Bologna, Italy). The beamformer design allows re-scaling to a greater number of beams and wider bandwidths.peer-reviewe

Sardinia Array Demonstrator: Instrument Overview and Status

In the framework of the Square Kilometer Array (SKA) project, the Italian Institute for Astrophysics (INAF) has addressed several efforts in the design and prototyping of aperture arrays for low-frequency radio astronomical research. The Sardinia Array Demonstrator (SAD) is a national project aimed to develop know-how in this area and to test different architectural technologies and calibration algorithms. SAD consists of 128 prototypical dual-polarized Vivaldi antennas designed to operate at radio frequencies below 650 MHz. The antennas will be deployed at the Sardinia Radio Telescope’s site with a versatile approach able to provide two different array configurations: (i) all antennas grouped in one large station or (ii) spread among a core plus few satellite stations. This paper provides an overview of the SAD project from an instrumental point of view, and illustrates its status after 2 years from its start

Concetti igienistici: Rischio Radon e Radioprotezione. Tecnica Ospedaliera, aprile 2009:46-51.

La generazione di radon (gas nobi-le derivante dal decadimento dei radionuclidi primordiali: 235 Ura-nio, 238 Uranio e 232 Torio) liberato in natura dalla crosta terrestre e immesso in atmosfera, in caso d’accumulo in ambienti confi nati di lavoro, di comunità e di vita, può essere un serio problema di pre-venzione lavorativa e sanità pubblica per la capacità d’indurre gravi patologie in persone esposte. La Iarc-Oms classifi ca il radon tra i cancerogeni di gruppo 1. In atmosfera vi so-no suoi valori minimi d’attività dell’ordine di 10-20 Bq/m³), senza rischi per la salute uma-na. In ambienti confi nati - specie se edifi cati in aree geografi che più ricche di radionuclidi, se a basso ricambio d’aria naturale o artifi cia-le, se costruiti con materiali a lento rilascio, se in presenza di polveri sottili derivanti da lavorazioni o da scarsa pulizia degli ambienti - esso, direttamente o congiuntamente alla sua progenie solida (222 Polonio), è un possibile rischio anche alto per la sua concentrazione e dose. Secondo l’Icrp (publication 60 del ‘90), l’esposizione associata a radon e fumo anche passivo implica l’aumento di 10-20 volte del rischio di cancro del polmone