Results on radiation tolerance of diamond detectors Venturi, N.; Alexopoulos, A.; Bachmair, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2018, Letnik:
924
Journal Article
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In sight of the luminosity increase of the High Luminosity-LHC (HL-LHC), most experiments at the CERN Large Hadron Collider (LHC) are planning upgrades for their innermost layers in the next 5–10 ...years. These upgrades will require more radiation tolerant technologies than exist today. Usage of Chemical Vapor Deposition (CVD) diamond as detector material is one of the potentially interesting technologies for the upgrade. CVD diamond has been used extensively in the beam condition monitors of BaBar, Belle, CDF and all LHC experiments. Measurements of the radiation tolerance of the highest quality polycrystalline CVD material for a range of proton energies, pions and neutrons obtained with this material are presented. In addition, new results on the evolution of various semiconductor parameters as a function of the dose rate are described.
In a previous study, the light scattering characteristics of clusters made up of 2 to 165 spheres were computed using coupled electric and magnetic dipole method. That study focused on comparing ...results with an exact solution and with a Rayleigh-Debye analysis for fixed orientations. Here, the authors extend the treatment to include orientation averaging and large agglomerates with up to 1390 spheres to allow comparison with other models and experiments. The primary focus of this analysis is to determine the effect of cluster size and primary sphere size on both the specific light extinction coefficient and the polarization ratio for smoke agglomerates. (AIAA)
Diamond detector technology, status and perspectives Kagan, H.; Alexopoulos, A.; Artuso, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2018, Letnik:
924
Journal Article
Recenzirano
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Detectors based on Chemical Vapor Deposition (CVD) diamond have been used extensively and successfully in beam conditions/beam loss monitors as the innermost detectors in the highest radiation areas ...of Large Hadron Collider (LHC) experiments. The startup of the LHC in 2015 brought a new milestone where the first polycrystalline CVD (pCVD) diamond pixel modules were installed in an LHC experiment and successfully began operation. The RD42 collaboration at CERN is leading the effort to develop polycrystalline CVD diamond as a material for tracking detectors operating in extreme radiation environments. The status of the RD42 project with emphasis on recent beam test results is presented.
A frame-transfer silicon charge-coupled-device (CCD) imager has been developed that can be closely abutted to other imagers on three sides of the imaging array. It is intended for use in multichip ...arrays. The device has 420*420 pixels in the imaging and frame-store regions and is constructed using a three-phase triple-polysilicon process. Particular emphasis has been placed on achieving low-noise charge detection for low-light-level imaging in the visible and maximum energy resolution for X-ray spectroscopic applications. Noise levels of 6 electrons at 1-MHz and less than 3 electrons at 100-kHz data rates have been achieved. Imagers have been fabricated on 1000- Omega cm material to maximize quantum efficiency and minimize split events in the soft X-ray regime.< >
Canalicular adenoma is a recently classified uncommon salivary gland neoplasm. This biologically benign growth tends to be multifocal and occurs most often in the upper lips of elderly people. ...Histologically and clinically it differs from the basal cell adenoma, for which it may be mistaken, in a number of ways. Its clinical importance lies in the fact that it may be confused with malignancy. Little information is available regarding the recurrence and long-term follow-up of these tumours, and where available it covers only relatively short periods. We report the recurrence of a canalicular adenoma after an 11.2 year disease-free period.
Verrucous carcinoma is a distinct variant of well differentiated squamous cell carcinoma. Its occurrence in the maxillary antrum is rare. Only three cases have previously been documented. We present ...a case report of verrucous carcinoma in the maxillary antrum and a review of the literature.
The LHCb experiment is preparing for a major upgrade in 2018–2019. One of the key components in the upgrade is a new silicon tracker situated upstream of the analysis magnet of the experiment. The ...Upstream Tracker (UT) will consist of four planes of silicon strip detectors, with each plane covering an area of about 2m2. An important consideration of these detectors is their performance after they have been exposed to a large radiation dose. In this paper we present test beam results of pre-prototype n-in-p and p-in-n sensors that have been irradiated with fluences up to 4.0×1014neq/cm2.
In this paper, we investigated the role of tribocharging in fluidization, flowability, and q/m distribution as functions of particle size distribution (PSD), fluidization time, and transport tubes of ...different materials. A charge separator was used to determine mass fractions of powder that had positive, zero, and negative charges. For the two acrylic powders tested, one (Sample A) had volume median diameter d/sub 50/ 18.73 /spl mu/m while the other (Sample B) had d/sub 50/ 24.17-/spl mu/m diameter. During fluidization for 1 h at a relative humidity of 57%, powder B acquired positive charge with charge-to-mass ratio Q/M=0.3 /spl mu/C/g, and 25% of the powder mass had negative charge with Q/M=-0.36 /spl mu/C/g. About 35% of the powder mass had particles with nearly zero net charge. Tribocharging during fluidization and transport processes was attributed to particle-particle and particle-wall collisions. Of the total charged particles, about 60% were positively charged while 40% were negatively charged. Each particle may have had patches of charges on its surface, some positive and some negative. The sum total of all patches of charges may yield positive, negative, or essentially neutral polarities on a given particle. For a relatively narrow size distribution of powder, the PSD is often assumed to be conserved during fluidization. A shift in PSD toward larger diameter particles was anticipated because of the possible elutriation of the fine fraction of the powder, but the actual shift was only about 1 /spl mu/m after 1 h of fluidization. Under identical operational conditions using a fluidized bed, powder pump, transport hose, and corona gun, powder B had nearly twice the mass flow rate of Powder A. Such differences in flowability of powders influence charging and deposition efficiencies in powder coating applications.
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