1,721,311 research outputs found
CHANNEL - CERN
No full textThe possibility to master negatively charge particle beams via coherent interaction with crystals would lead to several interesting opportunities, spanning from halo collimation in future accelerator machines with hundreds GeV-TeV electrons and positrons, to be the basis of a periodically bent crystal for miniature electron crystalline undulator in the GeV energy range, which is accessible by most electron accelerators worldwide. Achievement of such goals does demand greater knowledge on coherent interactions for negative particles, expecially for electrons.
Main purpose of this project is the investigation on the coherent interaction of negatively charged leptons with crystals in an wide energy range that goes from hundreds of MeV to 100 GeV
Sequence-based prioritization of i-Motif candidates in the human genome
No full textIntroduction: i-Motifs (iMs) are cytosine-rich, four-stranded DNA structures with emerging roles in gene regulation and genome stability. Despite their biological relevance, genome-wide prediction of iM-forming sequences remains limited by low specificity and high false-positive rates, leading to considerable experimental burden. Method: To address this, we developed a refined computational approach that prioritizes high-confidence iM candidates using a Position-Specific Similarity Matrix (PSSM) derived from multiple sequence alignments. The human reference genome (hg38) was scanned using a custom regular expression targeting cytosine-rich motifs, followed by scoring each sequence with the PSSM. Statistical significance was assessed via permutation testing, one-sided t-tests, Benjamini-Hochberg correction, and Z-scores. Results: This pipeline identified 37,075 candidate sequences (15–46 nucleotides) with strong iM-forming potential. Validation against experimentally confirmed iMs and known G-quadruplexes (G4s) demonstrated significant differences in alignment scores and sequence similarity, confirming structural specificity. A random forest classifier trained on nucleotide features further supported the distinctiveness of the candidates, achieving a high classification performance. Conclusion: This work presents a scalable and statistically robust method to enrich for biologically relevant iM sequences, providing a valuable resource for future experimental validation and the rational design of ligands targeting iMs to modulate gene expression in contexts such as cancer
CHANEL -INFN
No full textThe possibility to master negatively charge particle beams via coherent interaction with crystals would lead to several interesting opportunities, spanning from halo collimation in future accelerator machines with hundreds GeV-TeV electrons and positrons, to be the basis of a periodically bent crystal for miniature electron crystalline undulator in the GeV energy range, which is accessible by most electron accelerators worldwide. Achievement of such goals does demand greater knowledge on coherent interactions for negative particles, expecially for electrons.
Main purpose of this project is the investigation on the coherent interaction of negatively charged leptons with crystals in an wide energy range that goes from hundreds of MeV to 100 GeV
A microstrip silicon telescope for high performance particle tracking
No full textBent crystals are thin silicon/germanium devices that act as a bulk dipole magnet and thus are able to deflect relativistic charged particle beams with high efficiency (up to 98%). To study their behavior on extracted beamlines in terms of deflection capability and efficiency, a fast and high position resolution telescope is needed such as the INSULAB telescope.
It consists in several modules equipped with double or single side silicon detectors readout by different ASICs. The Data Acquisition system is designed to work with pulsed beams minimizing the dead time to allow the collection of a large statistics in a short time. It is based on custom VME readout/memory boards for the data storage and 12 bit ADC custom boards for the signal digitization; the present maximum DAQ rate is 6 kHz.
A detailed description of the detectors, the ASICs and the readout system together with the results obtained at the SPS H4 and PS T9 CERN beamlines in terms of spatial resolution and charge sharing are presented
A modular DAQ system for next generation bolometric v mass experiments
No full textThis work will describe the development and the present status of the new DAQ system for the MARE experiment. This kind of DAQ system is oriented to a run-time selection and digitization of analog signals coming from a huge number of microbolometers in a
cryogenic environment, readout by an array of semiconductor thermistors. The main properties of this DAQ are a full analog signal sampling feature with high speed FPGA-controlled trigger logic for a fast hardware signal selection and trigger. This DAQ system has to be capable to collect and measure the beta spectrum of 187Re with high statistics and energy resolution, essential for the neutrino mass determination
Study of the readout configuration of the GAMMA-400 silicon tracker sensors
No full textThe GAMMA-400 satellite is an upcoming international space mission designed to detect gamma and cosmic rays in a broad energy range up to 3 TeV, with an excellent angular and energy resolution. The present design foresees a 10 layers Si-W tracker formed by single sided silicon sensors with 80 um strip pitch, with a readout pitch of 240 um; the sensors are arranged in four towers, each one with an area of 50 x 50 cm(2), for a total of more than 150k channels. This paper presents an analysis of the spatial resolution of the proposed readout configuration, compared with different readout approaches, both in terms of readout pitch and strip/implant widths. The study has been performed with two specially developed silicon modules, each one divided into zones with different characteristics. The tests have been performed on the CERN PS-T9 beamline using 10 GeV negative particles
Dysprosium detector for neutron dosimetry in external beam radiotherapy
No full textRadiotherapy treatments with high-energy (> 8 MeV) photon beams are a standard procedure in clinical practice, given the skin and near-target volumes sparing effect, the accurate penetration and the uniform spatial dose distribution. On the other hand, despite these advantages, neutrons may be produced via the photo-nuclear (gamma,n) reactions of the high-energy photons with the high-Z materials in the accelerator head, in the treatment room and in the patient, resulting in an unwanted dose contribution which is of concern, given its potential to induce secondary cancers, and which has to be monitored. This work presents the design and the test of a portable Dysprosium dosimeter to be used during clinical treatments to estimate the "in vivo" dose to the patient. The dosimeter has been characterized and validated with tissue-equivalent phantom studies with a Varian Clinical iX 18 MV photon beam, before using it with a group of patients treated at the S. Anna Hospital in Como. The working principle of the dosimeter together with the readout chain and the results in terms of delivered dose are presented
A SiPM based readout system for lead tungstate crystals
No full textIn recent years Silicon PhotoMultipliers (SiPMs) have been proposed as a new type of readout system for scintillating detectors in many experiments. SiPMs consist of a matrix of parallel-connected silicon micro-pixels, which are independent photon counters working in limited Geiger mode with very high gain (similar to 10(6)). This contribution presents the use of SiPMs (manufactured by FBK-irst) as the readout system of a 3 x 3 matrix of lead tungstate crystals. The PbWO4 crystals have been provided by the CMS-ECAL group and are pre-production prototypes of the endcap section of the CMS electromagnetic calorimeter; they have a trapezoidal shape (with a front section of 2.86 x 2.86 cm(2) and a rear one of 2.96 x 2.96 cm(2)) and are 22 cm long, corresponding to 24.7X(0). Each crystal is readout using four SiPMs characterized by an active area of 4 x 4 mm(2) and 6400 cells, hosted on the same PCB. The gain equalization of the different SiPMs and its variation with the temperature is corrected using a LED system directly integrated on each PCB. A front-end board based on the MAROC3 ASIC has been used for the readout of the SiPMs signal. The performance of the crystal matrix in terms of linearity and energy resolution has been tested in November 2012 at CERN at the SPS-H2 and PS-T9 beamlines in the 1-150 GeV energy range
Design production and test of the BaBar SVT fanouts
No full textThe Silicon Vertex Tracker (SVT) of the BaBar experiment at the PEP-II B-factory at SLAG plays a fundamental role for the CP-violation measurement. The SVT is made of five layers of double-sided silicon microstrip detectors covering the polar angles between 17.2 degrees and 150 degrees (in the Upsilon(4S) center-of-mass reference frame this corresponds to -0.95 < cos theta < 0.87).
Due to mechanical constraints, the strip signals must be brought to the readout electronics with flexible Upilex circuits (fanouts) where copper traces are deposited with a pitch of approximate to 50 mu m.
We present here a detailed description of the mechanical and electric characteristics of these fanouts, with particular attention on the test system that has been designed in order to control the quality of the production
Exploiting the wide dynamic range of silicon photomultipliers for quantum optics applications
Full text linkSilicon photomultipliers are photon-number-resolving detectors endowed with hundreds of cells enabling them to reveal high-populated quantum optical states. In this paper, we address such a goal by showing the possible acquisition strategies that can be adopted and discussing their advantages and limitations. In particular, we determine the best acquisition solution in order to properly reveal the nature, either classical or nonclassical, of mesoscopic quantum optical states
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