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Search Results: 1 - 10 of 208447 matches for " L. Gironi "
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Pulse Shape Analysis with scintillating bolometers
L. Gironi
Physics , 2011, DOI: 10.1007/s10909-012-0478-x
Abstract: Among the detectors used for rare event searches, such as neutrinoless Double Beta Decay (0$\nu$DBD) and Dark Matter experiments, bolometers are very promising because of their favorable properties (excellent energy resolution, high detector efficiency, a wide choice of different materials used as absorber, ...). However, up to now, the actual interesting possibility to identify the interacting particle, and thus to greatly reduce the background, can be fulfilled only with a double read-out (i.e. the simultaneous and independent read out of heat and scintillation light or heat and ionization). This double read-out could greatly complicate the assembly of a huge, multi-detector array, such as CUORE and EURECA. The possibility to recognize the interacting particle through the shape of the thermal pulse is then clearly a very interesting opportunity. While detailed analyses of the signal time development in purely thermal detectors have not produced so far interesting results, similar analyses on macro-bolometers ($\sim$10-500 g) built with scintillating crystals showed that it is possible to distinguish between an electron or $\gamma$-ray and an $\alpha$ particle interaction (i.e. the main source of background for 0$\nu$DBD experiments based on the bolometric technique). Results on pulse shape analysis of a CaMoO$_4$ crystal operated as bolometer is reported as an example. An explanation of this behavior, based on the energy partition in the heat and scintillation channels, is also presented.
Scintillating bolometers for Double Beta Decay search
Luca Gironi
Physics , 2009, DOI: 10.1016/j.nima.2009.10.080
Abstract: In the field of Double Beta Decay (DBD) searches, the use of high resolution detectors in which background can be actively discriminated is very appealing. Scintillating bolometers containing a Double Beta Decay emitter can largely fulfill this very interesting possibility. In this paper we present the latest results obtained with CdWO4 and CaMoO4 crystals. Moreover we report, for the first time, a very interesting feature of CaMoO4 bolometers: the possibility to discriminate beta-gamma events from those induced by alpha particles thanks to different thermal pulse shape.
Supercritical Equilibrium Data of the Systems Carbon Dioxide—Linalool and Carbon Dioxide—Orange Essential Oil  [PDF]
Claudio Capparucci, Sara Frattari, Fausto Gironi
American Journal of Analytical Chemistry (AJAC) , 2013, DOI: 10.4236/ajac.2013.412093
Abstract:

In this paper experimental equilibrium data on the system supercritical CO2-orange essential oil and the system supercritical CO2-linalool are reported at 323.15 K and 343.15 K, for pressures in the ranges of 7.6-13.5 MPa. The behavior of the system supercritical CO2-orange essential oil was represented by means of thermodynamic model, based on Peng-Robinson equation of state. To this aim the orange essential oil was represented by a mixture of limonene, linalool and β-caryophyllene, selected to represent the classes of monoterpenes, oxygenated terpenes and sesquiterpenes respectively. The model uses only regression parameters calculated from binary sub-systems, CO2-limonene and CO2-β-caryophyllene (taken from literature) and CO2-linalool (calculated from the fitting of original data reported in the present work) thus being predictive with respect to the multicomponent mixture.

 

CdWO4 bolometers for Double Beta Decay search
L. Gironi,C. Arnaboldi,S. Capelli,O. Cremonesi,M. Pavan,G. Pessina,S. Pirro
Physics , 2008,
Abstract: In the field of Double Beta Decay (DBD) searches the possibility to have high resolution detectors in which background can be discriminated is very appealing. This very interesting possibility can be largely fulfilled in the case of a scintillating bolometer containing a Double Beta Decay emitter whose transition energy exceeds the one of the natural gamma line of 208Tl. We present the latest results obtained in the development of such a kind of scintillating bolometer. For the first time an array of five CdWO4 (116Cd has a Double Beta Decay transition energy of 2805 keV) crystals is tested. The array consists of a plane of four 3x3x3 cm3 crystals and a second plane consisting of a single 3x3x6 cm3 crystal. This setup is mounted in hall C of the National Laboratory of Gran Sasso inside a lead shielding in order to reduce as far as possible the environmental background. The aim of this test is to demonstrate the technical feasibility of this technique through an array of detectors and perform a long background measurement in the best conditions in order to prove the achievable background in the Zero neutrino-DBD region.
Characterization of ZnSe scintillating bolometers for Double Beta Decay
C. Arnaboldi,S. Capelli,O. Cremonesi,L. Gironi,M. Pavan,G. Pessina,S. Pirro
Physics , 2010, DOI: 10.1016/j.astropartphys.2010.09.004
Abstract: ZnSe scintillating bolometers are good candidates for future Double Beta Decay searches, because of the 82Se high Q-value and thanks to the possibility of alpha background rejection on the basis of the scintillation signal. In this paper we report the characteristics and the anomalies observed in an extensive study of these devices. Among them, an unexpected high emission from alpha particles, accompanied with an unusual pattern of the light vs. heat scatter plot. The perspectives for the application of this kind of detectors to search for the Neutrinoless Double Beta Decay of 82Se are presented.
A novel technique of particle identification with bolometric detectors
C. Arnaboldi,C. Brofferio,O. Cremonesi,L. Gironi,M. Pavan,G. Pessina,S. Pirro,E. Previtali
Physics , 2010, DOI: 10.1016/j.astropartphys.2011.02.006
Abstract: We report in this paper the proofs that the pulse shape analysis can be used in some bolometers to identify the nature of the interacting particle. Indeed, while detailed analyses of the signal time development in purely thermal detectors have not produced so far interesting results, similar analyses on bolometers built with scintillating crystals seem to show that it is possible to distinguish between an electron or gamma-ray and an alpha particle interaction. This information can be used to eliminate background events from the recorded data in many rare process studies, especially Neutrinoless Double Beta decay search. Results of pulse shape analysis of signals from a number of bolometers with absorbers of different composition (CaMoO4, ZnMoO4, MgMoO4 and ZnSe) are presented and the pulse shape discrimination capability of such detectors is discussed.
Performance of a large TeO2 crystal as a cryogenic bolometer in searching for neutrinoless double beta decay
L. Cardani,L. Gironi,J. W. Beeman,I. Dafinei,Z. Ge,G. Pessina,S. Pirro,Y. Zhu
Physics , 2011, DOI: 10.1088/1748-0221/7/01/P01020
Abstract: Bolometers are ideal devices in the search for neutrinoless Double Beta Decay. Enlarging the mass of individual detectors would simplify the construction of a large experiment, but would also decrease the background per unit mass induced by alpha-emitters located close to the surfaces and background arising from external and internal gamma's. We present the very promising results obtained with a 2.13 kg TeO2 crystal. This bolometer, cooled down to a temperature of 10.5 mK in a dilution refrigerator located deep underground in the Gran Sasso National Laboratories, represents the largest thermal detector ever operated. The detector exhibited an energy resolution spanning a range from 3.9 keV (at 145 keV) to 7.8 keV (at the 2615 gamma-line of 208Tl) FWHM. We discuss the decrease in the background per unit mass that can be achieved increasing the mass of a bolometer.
Monte Carlo evaluation of the external gamma, neutron and muon induced background sources in the CUORE experiment
F. Bellini,C. Bucci,S. Capelli,O. Cremonesi,L. Gironi,M. Martinez,M. Pavan,C. Tomei,M. Vignati
Physics , 2009, DOI: 10.1016/j.astropartphys.2010.01.004
Abstract: CUORE is a 1 ton scale cryogenic experiment aiming at the measurement of the Majorana mass of the electron neutrino. The detector is an array of 988 TeO2 bolometers used for a calorimetric detection of the two electrons emitted in the BB0n of 130Te. The sensitivity of the experiment to the lowest Majorana mass is determined by the rate of background events that can mimic a BB0n. In this paper we investigate the contribution of external sources i.e. environmental gammas, neutrons and cosmic ray muons to the CUORE background and show that the shielding setup designed for CUORE guarantees a reduction of this external background down to a level <1.0E-02 c/keV/kg/y at the Q-value, as required by the physical goal of the experiment.
CdWO4 scintillating bolometer for Double Beta Decay: Light and Heat anticorrelation, light yield and quenching factors
C. Arnaboldi,J. W. Beeman,O. Cremonesi,L. Gironi,M. Pavan,G. Pessina,S. Pirro,E. Previtali
Physics , 2010, DOI: 10.1016/j.astropartphys.2010.06.009
Abstract: We report the performances of a 0.51 kg CdWO4 scintillating bolometer to be used for future Double Beta Decay Experiments. The simultaneous read-out of the heat and the scintillation light allows to discriminate between different interacting particles aiming at the disentanglement and the reduction of background contribution, key issue for next generation experiments. We will describe the observed anticorrelation between the heat and the light signal and we will show how this feature can be used in order to increase the energy resolution of the bolometer over the entire energy spectrum, improving up to a factor 2.6 on the 2615 keV line of 208Tl. The detector was tested in a 433 h background measurement that permitted to estimate extremely low internal trace contaminations of 232Th and 238U. The light yield of gamma/beta, alpha and neutrons is presented. Furthermore we developed a method in order to correctly evaluate the absolute thermal quenching factor of alpha particles in scintillating bolometers.
Growth Hormone and Disease Severity in Early Stage of Multiple Sclerosis
M. Gironi,C. Solaro,C. Meazza,M. Vaghi,L. Montagna,M. Rovaris,A. P. Batocchi,R. Nemni,R. Albertini,M. Zaffaroni,M. Bozzola
Multiple Sclerosis International , 2013, DOI: 10.1155/2013/836486
Abstract: Evidence suggests that neurohormones such as GH and IGF-I are involved in the neuroreparative processes in multiple sclerosis (MS). GH and IGF-I blood levels in na?ve MS patients with different disease courses were investigated in this study. Serum GH and IGF-I in untreated MS patients ( ), healthy controls (HC, ), and patients affected by other neurological diseases (OND, ) were evaluated with a solid-phase-enzyme-labeled-chemiluminescent-immunometric assay. No differences were detected in GH across MS, OND, and HC ( ?ng/mL; ; and ; ) when considering gender, disease duration, and disease course. However, GH was lower ( ) in patients with more severe disease (expanded disability scale score, ) compared with milder forms ( ). IGF-I l did not differ across the 3 groups ( ), as far as concern disease course, disability, and gender were. Lower IGF-I levels were detected in subjects older than 50 years compared to younger ones for all 3 groups. Lower GH was detected in patients with more severe MS, and age was confirmed as the main factor driving IGF-I levels in all subjects. These findings, relying on the natural course of the disease, could help in shedding lights on the mechanisms involved in autoreparative failure associated with poorer prognosis in MS. 1. Introduction Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system with an unpredictable time course. Among the plethora of factors affecting the clinical heterogeneity of MS, autoreparative mechanisms are of particular importance. Remyelination is largely known to occur in MS [1], but it is still unclear why its adequacy differs so largely among patients. Many factors have been proposed to influence remyelination, including several neuroendocrine factors [2, 3]. Unresponsiveness to these factors and/or their insufficient release could possibly be involved in reparative mechanism failure, and studies focusing on these molecules have attracted a great deal of attention. Growth hormone and IGF-I have been recognised as factors that can affect survival of myelin and central nervous system (CNS) cells [3, 4]. Several studies [2–4] have focused on these growth factors, unfortunately with equivocal results. Heterogeneity is not largely dependent on the different methodologies used but also on the disease’s natural history. Growth factor bioavailability can vary in the different phases of the disease leading to a permissive or, on the contrary, an inadequate microenvironment supporting remyelination. Moreover, another putative confounding factor could be the different
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