Characterisation of a Thin Fully Depleted SOI Pixel Sensor with High Momentum Charged Particles

This paper presents the results of the characterisation of a thin, fully depleted pixel sensor manufactured in SOI technology on high-resistivity substrate with high momentum charged particles. The sensor is thinned to 70 $\mu$m and a thin phosphor layer contact is implanted on the back-plane. Its response is compared to that of thick sensors of same design in terms of signal and noise, detection efficiency and single point resolution based on data collected with 300 GeV pions at the CERN SPS. We observe that the charge collected and the signal-to-noise ratio scale according to the estimated thickness of the sensitive volume and the efficiency and single point resolution of the thinned chip are comparable to those measured for the thick sensors.Comment: 8 pages, 3 figures, submitted to Nucl. Instr. and Meth., section

Characterisation of a Thin Fully-Depleted SOI Pixel Sensor with Soft X-ray Radiation

This paper presents the results of the characterisation of a back-illuminated pixel sensor manufactured in Silicon-On-Insulator technology on a high-resistivity substrate with soft X-rays. The sensor is thinned and a thin Phosphor layer contact is implanted on the back-plane. The response to X-rays from 2.12 up to 8.6 keV is evaluated with fluorescence radiation at the LBNL Advanced Light Source.Comment: 9 pages, 5 figures, submitted to Nuclear Instruments and Methods

Foliations modeling nonrational simplicial toric varieties

We establish a correspondence between simplicial fans, not necessarily rational, and certain foliated compact complex manifolds called LVMB-manifolds. In the rational case, Meersseman and Verjovsky have shown that the leaf space is the usual toric variety. We compute the basic Betti numbers of the foliation for shellable fans. When the fan is in particular polytopal, we prove that the basic cohomology of the foliation is generated in degree two. We give evidence that the rich interplay between convex and algebraic geometries embodied by toric varieties carries over to our nonrational construction. In fact, our approach unifies rational and nonrational cases.Comment: 24 pages, 4 figures, expository changes, references updated. Link to the journal http://j.mp/BatZaf; Int. Math. Res. Not. 2015 (Published online February 24, 2015

Particle Identification for Physics beyond the LHC

Accelerator physics beyond the LHC is expected to provide precision in the study of new physics processes which the LHC may have already unveiled and to extend the high energy frontier beyond its reach, in the multi-TeV domain. In this paper I review the anticipated needs in terms of particle identification of this physics program in relation to the experimental conditions.Comment: 6 pages, 4 figures, invited contribution to the Second Workshop on advanced Transition Radiation Detectors for accelerators and space applications, Bari, September 200

Studies of Vertex Tracking with SOI Pixel Sensors for Future Lepton Colliders

This paper presents a study of vertex tracking with a beam hodoscope consisting of three layers of monolithic pixel sensors in SOI technology on high-resistivity substrate. We study the track extrapolation accuracy, two-track separation and vertex reconstruction accuracy in pion-Cu interactions with 150 and 300 GeV/c pions at the CERN SPS. Results are discussed in the context of vertex tracking at future lepton colliders.Comment: 15 pages, 8 figures, submitted to Nuclear Instruments and Methods

Doppler W-band polarization diversity space-borne radar simulator for wind studies

CloudSat observations are used in combination with collocated European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis to simulate spaceborne W-band Doppler observations from slant-looking radars. The simulator also includes cross-polarization effects which are relevant if the Doppler velocities are derived from polarization diversity pulse pair correlation. A specific conically scanning radar configuration (WIVERN), recently proposed to the ESA-Earth Explorer 10 call that aims to provide global in-cloud winds for data assimilation, is analysed in detail in this study. One hundred granules of CloudSat data are exploited to investigate the impact on Doppler velocity estimates from three specific effects: (1) non-uniform beam filling, (2) wind shear and (3) crosstalk between orthogonal polarization channels induced by hydrometeors and surface targets. Errors associated with non-uniform beam filling constitute the most important source of error and can account for almost 1 m s−1 standard deviation, but this can be reduced effectively to less than 0.5 m s−1 by adopting corrections based on estimates of vertical reflectivity gradients. Wind-shear-induced errors are generally much smaller (∼ 0.2 m s−1 ). A methodology for correcting these errors has been developed based on estimates of the vertical wind shear and the reflectivity gradient. Low signal-to-noise ratios lead to higher random errors (especially in winds) and therefore the correction (particularly the one related to the wind-shear-induced error) is less effective at low signal-to-noise ratio. Both errors can be underestimated in our model because the CloudSat data do not fully sample the spatial variability of the reflectivity fields, whereas the ECMWF reanalysis may have smoother velocity fields than in reality (e.g. they underestimate vertical wind shear). The simulator allows for quantification of the average number of accurate measurements that could be gathered by the Doppler radar for each polar orbit, which is strongly impacted by the selection of the polarization diversity H − V pulse separation, Thv. For WIVERN a selection close to 20 µs (with a corresponding folding velocity equal to 40 m s−1 ) seems to achieve the right balance between maximizing the number of accurate wind measurements (exceeding 10 % of the time at any particular level in the mid-troposphere) and minimizing aliasing effects in the presence of high winds. The study lays the foundation for future studies towards a thorough assessment of the performance of polar orbiting wide-swath W-band Doppler radars on a global scale. The next generation of scanning cloud radar systems and reanalyses with improved resolution will enable a full capture of the spatial variability of the cloud reflectivity and the in-cloud wind fields, thus refining the results of this study

The Vertex Tracker at Future e+e- Linear Colliders

The physics program of high energy e+e- linear colliders relies on the accurate identification of fermions to study in details the profile of the Higgs boson, search for new particles and later probe the multi-TeV mass region by direct searches and precision electro-weak measurements. This paper reviews the requirements, conceptual design and sensor R&D for the Vertex Tracker.Comment: 5 pages, to appear on the Proc. of th 6th Int. Conf. on Large Scale Applications and Radiation Hardness of Semiconductor Detectors, Firenze, September 200

Charting the Higgs Boson Profile e+e- Linear Colliders

The problems of the origin of mass and of electro-weak symmetry breaking are central to the programme of research in particle physics, at present and in the coming decades. This paper reviews the potential of high energy, high luminosity e+e- linear colliders in exploring the Higgs sector,to extend and complement the data which will become available from hadron colliders. The accuracy of measurements of the Higgs boson properties will not only probe the validity of the Higgs mechanism but also provide sensitivity to New Physics beyond the Standard Model.Comment: 16 pages, 8 figures, to appear in the Proc. of the 10th Int. Conference on Supersymmetry and Unification of Fundamental Interactions, DESY, Hamburg, June 200

Moser-Trudinger inequalities for singular Liouville systems

In this paper we prove a Moser-Trudinger inequality for the Euler-Lagrange functional of a general singular Liouville system. We characterize the values of the parameters which yield coercivity for the functional and we give necessary conditions for boundedness from below. We also provide a sharp inequality under some assumptions on the coefficients of the system.Comment: 22 pages, Accepted on Mathematische Zeitschrif