FAST FRONT-END ELECTRONICS FOR EXPERIMENTS USING SILICON CALORIMETERS AT SSC /LHC COLLIDERS

Abstract A fast VLSI preamplifier using HF2CMOS technology was designed and built. The preamplifier meets the requirements for silicon calorimetry application in experiments at hadron colliders SSC/LHC. The overall power consumption is less than 45 mW for a maximum output voltage swing of 5 V (≈ 7 ns rise time). The slew rate is about 700 V/μs for an input capacitance of 150 pF. The measured value of ENC (equivalent noise charge), for an RC-CR shaping time of 20 ns and an input capacitance of 150 pF, is 17 ke RMS

Monolithic read-out electronics for the silicon calorimeters at SSC/LHC colliders

Abstract A very fast monolithic charge sensitive preamplifier using HF2CMOS technology featuring less than 45mW power dissipation for a 5V maximum output voltage swing, with a slew rate about 700V/μsec for 150pF input capacitance (≈ 7nsec rise time), has been realized. A front-end set up for the read out of more detectors and the shaping of the signal with a 20nsec RC-CR filter employing only monolithic preamplifiers is described and tested. The measured value of ENC (Electronic Noise Charge) for the arrangement with 150pF input capacitance is 17keRMS. The preamplifier meets the requirements for silicon calorimetry application for experiments at the hadron colliders SSC/LHC

Damage distribution and seismological model of the November 24, 2004, Salo' (Northern Italy) earthquake

The West side of lake of Garda, in Northern Italy, was struck by a ML=5.2 earthquake on November 24, 2004. The felt area is rather large (from Venice to Milan) and the damaged area consists of 66 municipalities, with a number of homeless of about 2200 and estimated direct damages of 215 millions of euros. Most of the damaged structures are old masonry buildings and churches, while there were almost no damage to reinforced concrete structures. The observed distribution of macroseismic intensity shows a strong azimuthal dependence, with high intensity level in a 10x10 km2 area located SW to the epicentre and rather large dispersion of values (ranging from V to VII-VIII) in the first 10 km epicentral distance. Taking into account the vulnerability level of the damaged structures and the features of the geological formations, we tried to explain the observed damage distribution in terms of finite fault properties of the source, despite the moderate magnitude of the event. Thus we hypothesised a fault geometry from seismotectonic considerations and we simulated the event by a high frequency simulation technique (Deterministic Stochastic Method, DSM). The synthetic ground motion parameters were converted into intensity values by empirical relationships and local geological conditions were considered to explain some discrepancies between simulated and observed intensities. It was possible to adequately reproduce both the observed distribution of macroseismic intensity and the ground motion recorded by an accelerometric station located at about 13 km epicentral distance

Front-end Electronics and Optimal Ganging Schemes for Single Photon Detection with Large Arrays of SiPMs in Liquid Argon

The operation of large arrays of silicon photomultipliers (SiPM) in tanks of noble liquids requires low noise, low power front-end amplifiers, able to operate reliably in the cryogenic environment. A suitable amplifier needs to be paired with a proper SiPM ganging scheme, meaning the series/parallel combination of SiPMs at its input. This paper presents a simple model to estimate the ganging scheme that gives the best signal to noise ratio once the basic electrical characteristics of the SiPM and amplifier are known. To prove the validity of the model, we used an amplifier based on discrete components, which achieves a white voltage noise in the 0.25-0.37 nV/$\surd$Hz range at liquid nitrogen temperature, while drawing 2-5 mW of power. Combined with the optimal ganging scheme obtained with the model, the amplifier demonstrated excellent single photon sensitivity up to 96 6x6 mm$^2$ SiPMs (total area 34.6 cm$^2$, S/N $\simeq$ 8-11). The measured results are in a good match with calculated values, predicting the possibility to achieve a clear separation of photoelectron peaks also with larger areas

1.3 kg bolometers to search for rare events

Abstract Two TeO 2 crystal bolometers of 1.3 kg each, the largest single crystals ever operated with this technique, have been successfully realized and tested below 10 mK, in a dilution refrigerator located deep underground in the Gran Sasso National Laboratories. The calibration spectrum, obtained using an external 232Th γ -ray source, shows an energy resolution of 3–4 keV FWHM from 0.5 to 2.6 MeV, for both detectors. In the α region, a 4.3 keV FWHM resolution has been observed on the 5407 keV peak due to the α decay of 210Po, a natural contaminant of TeO 2 crystals

Effects of acute cigarette smoke exposure on macrophage kinetics and release of tumour necrosis factor α in rats

Some biological parameters before and after an acute episode of cigarette smoking in rats have been evaluated. The carboxyhaemoglobin levels depended either on the number of cigarettes, or on the time of exposure to cigarette smoke and returned to pre-smoking values in about 2 h. The evaluation of the kinetics of alveolar and peritoneal macrophages in rats after a smoking session of three cigarettes within an hour, indicated that alveolar macrophages in the bronchoalveolar lavage fluid significantly increased 8 h after the smoking, whereas the number of peritoneal macrophages remained practically constant. The incubation of these cells for various times at 37°C in a humidified atmosphere, resulted in a spontaneous release, 24 h thereafter, of variable amounts of tumour necrosis factor α (TNFα), which remained practically constant during the following days. Neither alveolar macrophages of control rats, nor peritoneal macrophages of both control and smoking rats were able to release TNFα. Moreover, after lipopolysaccharide induction of alveolar macrophages of both control and smoking rats, an increased release of TNFα was observed, indicating that these cells were in an active state