Search results for "Proton"
showing 10 items of 5886 documents
Proton Direct Ionization in Sub-Micron Technologies : Test Methodologies and Modelling
2023
Two different low energy proton (LEP) test methods, one with quasi-monoenergetic and the other with very wide proton beam energy spectra, have been studied. The two test methodologies have been applied to devices that were suggested from prior heavy-ion tests to be sensitive to proton direct ionization (PDI). The advantages and disadvantages of the two test methods are discussed. The test method using quasi-monoenergetic beams requires device preparation and high energy resolution beams, but delivers results that can be interpreted directly and can be used in various soft error rate (SER) calculation methods. The other method, using a heavily degraded high energy proton beam, requires littl…
High-gradient accelerating structure studies and their application in hadrontherapy
2013
198 páginas. Tesis doctoral del Departamento de Física Atómica, Molecular y Nuclear, de la Universidad de Valencia.
Dielectron and heavy-quark production in inelastic and high-multiplicity proton–proton collisions at √s = 13 TeV
2019
The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (pT) at midrapidity (|ye| < 0.8) in proton–proton (pp) collisions at a centre-of-mass energy of √s = 13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at √s = 7 TeV or 13 TeV. The remaining continuum stems from correlated semileptonic decays of heavy-flavour hadrons. Fitting the data with templates from two different MC event generators, PYTHIA and POWHEG, the charm and beauty cross sections at midrapidity are extracted for the first time at this collision energy: dσcc¯/dy|y=0 = 974 ± 138 (stat.) ± 140 (syst.) ± 214…
Charged-particle multiplicities in proton–proton collisions at √s = 0.9 to 8 TeV
2017
A detailed study of pseudorapidity densities and multiplicity distributions of primary charged particles produced in proton–proton collisions, at √s = 0.9, 2.36, 2.76, 7 and 8 TeV, in the pseudorapidity range |η| < 2, was carried out using the ALICE detector. Measurements were obtained for three event classes: inelastic, non-single diffractive and events with at least one charged particle in the pseudorapidity interval |η| < 1. The use of an improved track-counting algorithm combined with ALICE’s measurements of diffractive processes allows a higher precision compared to our previous publications. A KNO scaling study was performed in the pseudorapidity intervals |η| < 0.5, 1.0 and 1.5. The …
Measurement of pion, kaon and proton production in proton–proton collisions at √s = 7 TeV
2015
The measurement of primary π±, K ±, p and p production at mid-rapidity (|y| < 0.5) in proton–proton collisions at √s = 7 TeV performed with a large ion collider experiment at the large hadron collider (LHC) is reported. Particle identification is performed using the specific ionisation energy-loss and time-of-flight information, the ringimaging Cherenkov technique and the kink-topology identifi- cation of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/c for pions, from 0.2 up to 6 GeV/c for kaons and from 0.3 up to 6 GeV/c for protons. The measured spectra and particle ratios are compared with quantum chromodynamics-inspired models, tuned to repr…
Measurement of D-meson production at mid-rapidity in pp collisions at √s = 7 TeV
2017
The production cross sections for prompt charmed mesons D0, D+, D∗+ and D+s were measured at mid-rapidity in proton–proton collisions at a centre-of-mass energy s√=7 TeV with the ALICE detector at the Large Hadron Collider (LHC). D mesons were reconstructed from their decays D0→K−π+, D+→K−π+π+, D∗+→D0π+, D+s→ϕπ+→K−K+π+, and their charge conjugates.With respect to previous measurements in the same rapidity region, the coverage in transverse momentum (pT) is extended and the uncertainties are reduced by a factor of about two. The accuracy on the estimated total cc¯¯ production cross section is likewise improved. The measured pT-differential cross sections are compared with the results of thre…
Pseudorapidity and transverse-momentum distributions of charged particles in proton–proton collisions at √s = 13 TeV
2016
The pseudorapidity (η) and transverse-momentum (pT) distributions of charged particles produced in proton–proton collisions are measured at the centre-of-mass energy √s = 13 TeV. The pseudorapidity distribution in |η| < 1.8 is reported for inelastic events and for events with at least one charged particle in |η| < 1. The pseudorapidity density of charged particles produced in the pseudorapidity region |η| < 0.5 is 5.31 ± 0.18 and 6.46 ± 0.19 for the two event classes, respectively. The transverse-momentum distribution of charged particles is measured in the range 0.15 < pT < 20 GeV/c and |η| < 0.8 for events with at least one charged particle in |η| < 1. The evolution of the transverse mome…
Combined Spectroscopic and TD-DFT Analysis to Elucidate Substituent and Acidochromic Effects in Organic Dyes: A Case Study on Amino- versus Nitro-Sub…
2020
Made available in DSpace on 2020-12-12T01:33:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 A combined spectroscopic and TD-DFT case study was performed, to identify a robust method to calculate the complex near UV/Vis absorption spectra of various amino- vs. nitro-substituted 2,4-diphenylquinolines, which vary strongly under neutral and successively acidic conditions. For this, different DFT functionals were tested for geometry optimization and the TD part to calculate the neutral and different protonated species in a fast screening approach, i. e. using single point calculations in an implicit solvent. Offset-corrected M06HF, hitherto only applied to polymers, was identif…
A GEM-TPC in twin configuration for the Super-FRS tracking of heavy ions at FAIR
2018
The GEM-TPC [1] described herein will be part of the standard beam-diagnostics equipment of the Super-FRS [2] . This chamber will provide tracking information for particle identification at rates up to 1 MHz on an event-by-event basis. The key requirements of operation for these chambers are: close to 100% tracking efficiency under conditions of high counting rate, spatial resolution below 1 mm and a superb large dynamic range covering projectiles from Z=1 up to Z=92. The current prototype consists of two GEM-TPCs inside a single vessel, which are operating independently and have electrical drift fields in opposite directions. The twin configuration is done by flipping one of the GEM-TPCs o…
Proton reduction by phosphinidene-capped triiron clusters
2021
Bis(phosphinidene)-capped triiron carbonyl clusters, including electron rich derivatives formed by substitution with chelating diphosphines, have been prepared and examined as proton reduction catalysts. Treatment of the known cluster [Fe3(CO)9(µ3-PPh)2] (1) with various diphosphines in refluxing THF (for 5, refluxing toluene) afforded the new clusters [Fe3(CO)7(µ3-PPh)2(κ2-dppb)] (2), [Fe3(CO)7(µ3-PPh)2(κ2-dppv)] (3), [Fe3(CO)7(µ3-PPh)2(κ2-dppe)] (4) and [Fe3(CO)7(µ3-PPh)2(µ-κ2-dppf)] (5) in moderate yields, together with small amounts of the corresponding [Fe3(CO)8(µ3-PPh)2(κ1-Ph2PxPPh2)] cluster (x = -C4H6-, -C2H2-, -C2H4-, -C3H6-, -C5H4FeC5H4-). The molecular structures of complexes 3 a…