Search results for "Accelerator"
showing 10 items of 1507 documents
Laser spectroscopy for nuclear structure physics
2016
High-resolution laser spectroscopy is an established powerful tool in the study of nuclear shape, size and multipole moments. Measurements of the hyperfine structures and isotope shifts in the atomic spectra of radioactive nuclei provide unique insight into the evolution of the nuclear macroscopic shape and microscopic structure. These measurements can be made with high precision and high sensitivity and applied directly on-line at radioactive nuclear beam facilities. Recent measurements, advances at facilities and the future direction of the field are reviewed. A summary of experimental data is presented. peerReviewed
Penning trap at IGISOL
2002
The IGISOL facility [1] at the Department of Physics of the University of Jyvaskyla (JYFL) is delivering radioactive beams of short-lived exotic nuclei, in particular the neutron-rich isotopes from fission reaction. These nuclei are studied with the nuclear and collinear laser spectroscopy methods. In order to obtain a meaningful increase, in comparison to a standard level, of precision and sensitivity of such studies an improvement of the radioactive beam quality is necessary. This improvement will be achieved due to a radioactive beam handling which consists of three steps: beam cooling, bunching and (isobaric) purification. The latter means a possibility of obtaining a pure monoisotopic …
Precision experiments with time-resolved Schottky mass spectrometry
2004
Abstract A large area on the mass surface of neutron-deficient nuclides (36≤Z≤85) was measured with time-resolved Schottky mass spectrometry at the FRS-ESR facilities. The masses of 114 nuclides were obtained for the first time from which 43 were determined via known decay energies. The improved mass accuracy of 30 keV allowed to study the isospin dependence of nuclear pairing, to precisely locate the one-proton dripline for odd-Z isotopes from Tb to Pa and to make crucial tests of the predictive powers of modern mass models.
Atomic beam magnetic resonance apparatus for systematic measurement of hyperfine structure anomalies (Bohr-Weisskopf effect)
1993
Abstract An atomic beam magnetic resonance (ABMR) apparatus has been constructed at Orsay, and has been installed at the CERN PS Booster ISOLDE mass separator facility for “on-line” work with radioactive isotopes in a program to measure hyperfine structure anomalies (the Bohr-Weisskopf effect) over long isotopic chains. The hfs anomalies result from the effect of the spatial distribution of the nuclear magnetization on the atomic hfs interaction. Constructional details of the system are described: emphasis is placed on the measurement of nuclear g-factors by a triple resonance, laser state selected, ABMR method. A precision better than 10−4 for gI values has been obtained in stable atomic b…
Search for the Standard Model Higgs boson in the H→WW(⋆)→ℓνℓν decay mode with 4.7 fb−1 of ATLAS data at s=7 TeV
2012
A search for the Standard Model Higgs boson in the H -> WW(*()) -> lvlv (l = e.mu) decay mode is presented. The search is performed using proton-proton collision data corresponding to an inte ...
Structure of191Pb from α- and β-decay spectroscopy
2010
International audience; Complementary studies of 191 Pb have been made in the β decay of 191 Bi at LISOL (CRC) and in the α decay of 195 Po at ISOLDE (CERN). Fine structures in the α decay of the low-spin and high-spin isomers of 195 Po have been fully resolved. Identification of the parent state is made possible via isomer selection based on narrowband laser frequency scanning. The α-particle and γ-ray energies have been determined with greater precision. New α-particle and γ-ray energies are identified. Branching ratios in the decay of 195 Po and 191 Pb have been examined. Structure of 191 Pb from α- and β-decay spectroscopy 2 PACS numbers: 23.20.Nx Internal conversion, 23.60.+e α decay, …
Liquid argon calorimeter performance at high rates
2012
Abstract We project the performance of the ATLAS liquid argon endcap and forward calorimeters at the planned high luminosity LHC option HL-LHC by exposing small calorimeter modules of the electromagnetic, hadronic, and forward calorimeters to high intensity beams at IHEP/Protvino. The beam intensity extends well beyond the maximum expected for these calorimeters at HL-LHC. The signal reconstruction and calorimeter performance have been studied in full detail.
Deceleration of antiprotons from MeV to keV energies
1993
Trapping of antiprotons for high precision measurements at the Low Energy Antiproton Ring (LEAR/CERN) requires the deceleration of the antiproton beam from typically 5.8 MeV energy down to 10 keV for final capture in standard Penning traps. Two methods, the degradation of the beam in thin foils and the deceleration of the beam in an inverse cyclotron are investigated so far. The foil technique was successfully demonstrated with trapping efficiencies up to a few 10−4 and is now routinely used in the high precision measurement of the antiprotonproton mass ratio. The degradation foil method is compared with the deceleration technique using an inverse cyclotron tested also at LEAR.
Measurement of the polarization of $$\Lambda ^0 , \overline \Lambda ^0 , \Sigma ^ + $$ and ?? produced in a ?? beam of 330 GeV/c
1995
The polarization of Lambda0 , AntiLambda0 , Sigma+ and Xi- inclusively produced in Sigma- induced interactions at 330 GeV has been measured in the experiment WA89 at CERN. This is the first measurement of polarization of baryons produced by a hyperon beam. No polarization of AntiLambda is observed, as was also the case in proton beam data. At transverse momenta of about 1~GeV/c Lambda0 and Sigma+ show little polarization, significantly lower than in the proton beam data, while Xi- have a polarization comparable to the polarization of Lambda0 produced in proton beams. The polarization of Lambda0, AntiLambda0, Sigma+ and Xi- inclusively produced in Sigma- induced interactions at 330 GeV has b…
Optimal β-beam at the CERN-SPS
2005
A β-beam with maximum (for 6He ions) or (for 18Ne) could be achieved at the CERN-SPS. We study the sensitivity to and δ of such a beam as function of γ, optimizing with the baseline constrained to CERN–Frejus (130 km), and also with simultaneous variation of the baseline, for a fixed ion flux. These results are compared to the standard scenario previously considered, with lower , and also with a higher option that requires a more powerful accelerator. We conclude that the sensitivity to CP violation and increases significantly with γ if the baseline is increased proportionally, while for the CERN–Frejus scenario the dependence on γ is mild provided γ is above 100.