Investigation of the properties of a 1″×1″ LaBr3:Ce scintillator Nicolini, R.; Camera, F.; Blasi, N. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2007, Letnik:
582, Številka:
2
Journal Article
The investigation of light-ion reactions with exotic beams in inverse kinematics gives access to a comprehensive range of nuclear structure information in the region far off stability. The future ...FAIR facility at GSI will provide new opportunities to extend and advance these investigations. The present paper will focus on the results of the first feasibility experiment for the EXL project in which we used a stored
136Xe beam with
E = 350
MeV/nucleon interacting with an internal hydrogen gas-jet target at the ESR storage ring of GSI. In this experiment we made use of at least one element of every detector part of the future experimental setup. Selected results from this measurement will be presented.
The investigation of light-ion induced direct reactions in inverse kinematics, using stored and cooled radioactive beams, interacting with internal H, He, etc. gas-jet targets, bears a large ...potential for nuclear structure and astrophysics studies on exotic nuclei. An extended research project EXL has been accepted for the future facility FAIR in Darmstadt, Germany. In order to explore the experimental conditions for measurements planned at FAIR, a first test experiment for proving the feasibility of the EXL concept was performed.
Multi-nucleon transfer reactions are useful tools to populate exotic nuclei, particularly the neutron-rich ones. In this view, two different experiments have been performed employing a stable (22Ne) ...and a radioactive (24Ne) beam, both impinging on a 208Pb target. The first reaction has been studied using the CLARA-PRISMA-DANTE set-up at Laboratori Nazionali di Legnaro (Legnaro-Italy), while the second reaction was performed at Ganil (Caen-France) employing a SPIRAL radioactive beam of 24Ne. In this case recoils and coincident g rays were detected with the VAMOS-EXOGAM set-up.The data show that MNT reactions can selectively populate states of different nature and, therefore, are a good tool to study nuclear structure further away from stability.
Investigation of the properties of a 1″×1″ LaBr 3:Ce scintillator Nicolini, R.; Camera, F.; Blasi, N. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2007, Letnik:
582, Številka:
2
Journal Article
Recenzirano
The properties of a cylindrical 1″×1″ LaBr
3:Ce scintillator (Brillance 380) were investigated. The energy resolution at γ-ray energy of 662
keV was measured to be smaller than 3% and the intrinsic ...time resolution was found to be ≈230
ps. Two different aspects were investigated. The first is the detailed study of the crystal self-activity, emitting α and β particles and γ-rays, by measuring coincidences with γ-rays in HPGe, BGO and BaF
2 detectors. In particular, the coincidence with an HPGe detector allowed to isolate clearly the different contributions from
227Ac (chemical homologue of lanthanum) and its daughter nuclei down to the stable
207Pb. The second aspect is the determination of the efficiency for γ-ray detection, measured at 1
MeV and simulated using GEANT4 up to 15
MeV as a function of the detector size.
LEP measurements of the weak electric dipole moment
d
w
τ
and the weak anomalous magnetic dipole moment
a
ω
τ
of the τ lepton are reviewed and the search for CP violation in the production of τ pairs ...on the Z peak is discussed. Two methods of the measurement of the weak dipole moments based on the analysis of the transverse and normal components of single τ polarisation (azimuthal asymmetries) and spin-spin correlations (optimal observables) are discussed. Averaging the LEP measurements, upper limits on the weak electric dipole moment of the τ lepton are obtained.
Abstract Background/objectives Cachexia affects ∼80% of pancreatic cancer patients. An international consensus defines cachexia as an ongoing loss of skeletal muscle mass (sarcopenia) with or without ...loss of fat, which impairs body functioning and cannot be reversed by conventional nutritional measures. Weight loss percentage and elevated inflammation markers have been employed to define this condition earlier. This review aimed to assess the prevalence and consequences of cachexia and sarcopenia on survival in patients with pancreatic ductal adenocarcinoma. Methods The systematic review was performed by searching the articles with preset terms published in PubMed and Cochrane Database until December 2013. After identifying relevant titles, abstracts were read and eligible articles data retrieved on preformatted sheets. The prevalence and impact of sarcopenia/cachexia on survival was evaluated. Results In total 1145 articles were retrieved, only 10 were eligible. Definitions of cachexia and sarcopenia were heterogeneous. In patients with normal weight (BMI 18.5–24.9 kg/m2 ) the prevalence of sarcopenia ranged from 29.7 to 65%. In overweight or obese patients (BMI >25 kg/m2 ) were 16.2%–67%. Sarcopenia alone was not demonstrated to be an independent factor of decreased survival, although obese sarcopenic patients were shown to have significantly worse survival in two studies. Conclusions Impact of cachexia and sarcopenia on survival in pancreatic ductal adenocarcinoma is currently understudied in the available literature. Definitive association between cachexia and survival cannot be drawn from available studies, although weight loss and sarcopenic obesity might be considered as poor prognostic factors. Further prospective trials utilizing the consensus definition of cachexia and including other confounding factors are needed to investigate the impact of cachexia and sarcopenia on survival in pancreatic adenocarcinoma.
In this study, the interferometric coherence calculated from 12-day Sentinel-1 image pairs was analysed in relation to mowing events on agricultural grasslands. Results showed that after a mowing ...event, median VH (vertical transmit, horizontal receive) and VV (vertical transmit, vertical receive) polarisation coherence values were statistically significantly higher than those from before the event. The shorter the time interval after the mowing event and the first interferometric acquisition, the higher the coherence. The coherence tended to stay higher, even 24 to 36 days after a mowing event. Precipitation caused the coherence to decrease, impeding the detection of a mowing event. Given the three analysed acquisition geometries, it was concluded that afternoon acquisitions and steeper incidence angles were more useful in the context of this study. In the case of morning acquisitions, dew might have caused a decrease of coherence for mowed and unmowed grasslands. Additionally, an increase of coherence after a mowing event was not evident during the rapid growth phase, due to the 12-day separation between the interferometric acquisitions. In future studies, six-day pairs utilising Sentinel-1A and 1B acquisitions should be considered.
In this study, Sentinel-1 interferometric wide swath (IW) mode backscatter is analysed with respect to physical parameters of buildings in Tallinn, Estonia. Dependence on height, alignment, density, ...shape, and material is shown and discussed. Distribution of backscatter was estimated with respect to each of the parameters, and a correlation matrix of all physical parameters and backscatter values was computed. Height has the strongest effect on backscatter values for both polarization bands, while shape and alignment to orbit has weaker effect on the backscatter. Relationship of co-polarized and cross-polarized backscatter with how a building is aligned with respect to the satellite's look angle indicates that double bounce from wall-ground interactions is still the dominant scattering mechanism detected by Sentinel-1 in IW mode with 20 m resolution. In order to establish possible detection problems related to specifically oriented buildings at different latitudes, dihedral backscatter is modelled for buildings of oblong and square shapes. Results from this study should be used to improve existing and develop new urban area detection methods based on Sentinel-1 data.
In this study, four models describing the interferometric coherence of the forest vegetation layer are proposed and compared with the TanDEM-X data. Our focus is on developing tools for hemiboreal ...forest height estimation from single-pol interferometric SAR measurements, suitable for wide area forest mapping with limited a priori information. The multi-temporal set of 19 TanDEM-X interferometric pairs and the 90th percentile forest height maps are derived from Airborne LiDAR Scanning (ALS), covering an area of 2211 ha of forests over Estonia. Three semi-empirical models along with the Random Volume over Ground (RVoG) model are examined for applicable parameter ranges and model performance under various conditions for over 3000 forest stands. This study shows that all four models performed well in describing the relationship between forest height and interferometric coherence. Use of an advanced model with multiple parameters is not always justified when modeling the volume decorrelation in the boreal and hemiboreal forests. The proposed set of semi-empirical models, show higher robustness compared to a more advanced RVoG model under a range of seasonal and environmental conditions during data acquisition. We also examine the dynamic range of parameters that different models can take and propose optimal conditions for forest stand height inversion for operationally-feasible scenarios.
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