Search results for "accelerator"
showing 10 items of 1507 documents
Precision luminosity measurements at LHCb
2014
Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy $\sqrt{s}$. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for $\sqrt{s}$ = 2.76, 7 and 8 TeV (proton-proton collisions) and for $\sqrt{s_{NN}}$ = 5 TeV (proton-lead collisions). Both the "van der Meer scan" and "beam-gas imaging" luminosity calibration methods were employed. It is observed that the beam density profile cannot always be described by a function that is factorizable in the two transverse coordinates. The introduction of a two-dimensional description of the beams improves sig…
Detector for monitoring potential bleeding during electron intraoperative radiotherapy
2018
Purpose: The aim of this work is to develop a bleeding detector integrated into the acrylic circular applicators for specific mobile linacs. Thus, a bleeding detector has been developed based on a capacitive sensor to be used with plastic applicators, as in the case of LIAC HWL from Sordina IORT Technologies SpA. According to the clinical impact, we have selected 0.5 cm as the minimum depth of fluid that should be detected. Methods: An experiment was developed using water-simulating blood. Two setups were considered: non-beveled applicators with 7 cm and 10 cm diameter. Measurements were done for applicators 0 degrees and 45 degrees tilted, both with respect to the horizontal surface, in or…
Phantom development for daily checks in electron intraoperative radiotherapy with a mobile linac.
2020
Abstract Purpose IORT with mobile linear accelerators is a well-established modality where the dose rate and, therefore, the dose per pulse are very high. The constancy of the dosimetric parameters of the accelerator has to be checked daily. The aim of this work is to develop a phantom with embedded detectors to improve both accuracy and efficiency in the daily test of an IORT linac at the surgery room. Methods The developed phantom is manufactured with transparent polymethyl methacrylate (PMMA), allocating 6 parallel-plate chambers: a central one to evaluate the on-axis beam output, another on-axis one placed at a fixed depth under the previous one to evaluate the energy constancy and four…
The identification of autoionizing states of atomic chromium for the resonance ionization laser ion source of the ISOLDE radioactive ion beam facility
2017
Abstract This paper presents the results of an investigation into autoionizing states of atomic chromium, in the service of the resonance ionization laser ion source (RILIS): the principal ion source of the ISOLDE radioactive ion beam facility based at CERN. The multi-step resonance photo-ionization process enables element selective ionization which, in combination with mass separation, allows isotope specific selectivity in the production of radioactive ion beams at ISOLDE. The element selective nature of the process requires a multi-step “ionization scheme” to be developed for each element. Using the method of in-source resonance ionization spectroscopy, an optimal three-step, three-reson…
Space-Charge Effects with REXTRAP
2001
The beam quality of radioactive ion beams produced by present target ion source technology is often not sufficient for direct post-acceleration. Furthermore, pulsed beams insure a more efficient use of an accelerator. In the case of REX-ISOLDE, the post accelerator at the CERN ISOLDE facility, a gas-filled Penning trap (REXTRAP) has been chosen for accumulation of the radioactive ions and conversion into cooled bunches. Radial centering of the ions is achieved by applying an rf field with a frequency equal to the cyclotron frequency of the desired ion species. The efficiency achieved in the first tests with different isotopes covering nearly the entire mass range was already >20%. Going to …
Time Characteristics of the Ion Beam Cooler-Buncher at JYFL
2001
A beam cooler for low-energy ion beams was constructed to improve the ion optical properties of radioactive ion beams produced at the IGISOL facility in Jyvaskyla. The beam cooler is a buffer gas filled RF-quadrupole. The delay properties and the possibility to accumulate a continuous IGISOL beam and release it in short bunches is discussed.
CRIS: A new method in isomeric beam production
2013
The Collinear Resonance Ionization Spectroscopy (CRIS) experiment at ISOLDE, CERN, uses laser radiation to stepwise excite and ionize an atomic beam for the purpose of ultra-sensitive detection of rare isotopes, and hyperfine-structure measurements. The technique also offers the ability to purify an ion beam that is heavily contaminated with radioactive isobars, including the ground state of an isotope from its isomer, allowing decay spectroscopy on nuclear isomeric states to be performed. The isomeric ion beam is selected by resonantly exciting one of its hyperfine structure levels, and subsequently ionizing it. This selectively ionized beam is deflected to a decay spectroscopy station (DS…
Radium ionization scheme development: The first observed autoionizing states and optical pumping effects in the hot cavity environment
2018
© 2018 The Authors This paper reports on resonance ionization scheme development for the production of exotic radium ion beams with the Resonance Ionization Laser Ion Source (RILIS) of the CERN-ISOLDE radioactive ion beam facility. During the study, autoionizing states of atomic radium were observed for the first time. Three ionization schemes were identified, originating from the 7s2 1S0 atomic ground state. The optimal of the identified ionization schemes involves five atomic transitions, four of which are induced by three resonantly tuned lasers. This is the first hot cavity RILIS ionization scheme to employ optical pumping effects. The details of the spectroscopic studies are described …
Optimization of a hot-cavity type resonant ionization laser ion source
2015
TuePS05; International audience; Resonant Ionization Laser Ion Source (RILIS) is nowadays an important technique in many RadioactiveIon Beam (RIB) facilities for its reliability and ability to ionize efficiently and element selectively.Grand Accélérateur National d’Ions Lourds (GANIL) Ion Source using Electron Laser Excitation(GISELE) is an off-line test bench for RILIS developed to study a fully operational resonant laserion source at GANIL facility. The ion source body has been designed as a modular system toinvestigate different experimental approaches by varying the design parameters, to develop the futureon-line laser ion source. The aim of this project is to determine the best technic…
Laser spectroscopy of radioactive Ti, Zr and Hf isotopes and isomers at the JYFL laser-IGISOL facility
2003
Abstract The recent progress at the laser-ion guide isotope separator on-line facility, JYFL, is presented. At the facility new techniques for studying short-lived radioisotopes by laser spectroscopy have been developed and applied to the study of isotopes in refractory metal elements. In particular, recent results on the spectroscopy of cooled ion beams of radioactive Ti, Zr and Hf isotopes are discussed.