Search results for " Collider"
showing 10 items of 1415 documents
Production of molecular sideband radioisotope beams at CERN-ISOLDE using a Helicon-type plasma ion source
2013
In order to account for the increasing demand for strong molecular beams for nuclear physics experiments at ISOLDE, a new radioactive ion source concept based on an RE discharge in a magnetized plasma was developed at CERN. Experimental studies at the ISOLDE offline separator show that the optimum conditions for CO+ and CO2+ ion production are given when the ion source is operated with He plasma, in line with expectations based on their electron impact ionization cross-sections. At optimum tuning, ionization efficiencies of 2.5% and 4% were measured for CO+ and Ar+, respectively. The capability of the Helicon ion source prototype for ISOL operation was evaluated during two online runs at th…
First measurement of f′2 (1525) production in Z0 hadronic decays
1996
The inclusive production of the f(2)'(1525) in hadronic Z(0) decays has been studied in data collected by the DELPHI detector at LEP. The Ring Imaging Cherenkov detectors were important tools in the identification of the decay f(2)'(1525) --> K+K-. The average number of f(2)(')(1525) produced per hadronic Z decay, [f(2)'] = 0.020 +/- 0.005 (stat) +/- 0.006 (syst), and the momentum distribution of the f(2)'(1525) have both been measured. The mass and width of the f(2)'(1525) are found to be [M(f2)'] = 1535 +/- 5 (stat) +/- 4 (syst) MeV/c(2). [Gamma(f2)'] = 60 +/- 20 (stat) +/- 19 (syst) MeV/c(2)
The REX-ISOLDE project
1998
Abstract REX-ISOLDE [1] is an experiment at ISOLDE/CERN with a twofold aim: (i) to demonstrate a novel efficient scheme for the acceleration of radioactive ions from the online mass separator ISOLDE to energies around the Coulomb barrier. (ii) to perform first nuclear physics experiments by studying the structure of the neutron-rich (N = 20, N = 28) nuclei by Coulomb excitation and neutron transfer reactions. An overview on the different components of the radioactive beam accelerator is given with special emphasis on the separation possibilities and ion number capabilities of the system.
First laser ions at an off-line mass separator of the ISAC facility at TRIUMF
2004
For efficient and in particular for selective production of radioactive ion beams at on-line mass separator facilities the technique of resonance ionization laser ion sources (RILIS) has become the most powerful tool. In facilities like ISOLDE at CERN they nowadays represent the most commonly used type of ion source for rare short-lived isotopes, delivering highest suppression of isobaric contaminations. For a first off-line demonstration preparing the development and installation of such a laser ion source at the new ISAC facility at TRIUMF in Vancouver (Canada), an all solid state laser system developed at the University of Mainz (Germany), was transferred and tested there at an off-line …
Data acquisition, remote control and equipment monitoring for ISOLDE RILIS
2013
Abstract With a steadily increasing on-line operation time up to a record 3000 h in the year 2012, the Resonance Ionization Laser Ion Source (RILIS) is one of the key components of the ISOLDE on-line isotope user facility at CERN. Ion beam production using the RILIS is essential for many experiments due to the unmatched combination of ionization efficiency and selectivity. To meet the reliability requirements the RILIS is currently operated in shift duty for continuous maintenance of crucial laser parameters such as wavelength, power, beam position and timing, as well as ensuring swift intervention in case of an equipment malfunction. A recent overhaul of the RILIS included the installation…
Towards higher accuracy with the ISOLTRAP mass spectrometer
1996
To now the masses of more than hundred unstable isotopes have been determined with the ISOLTRAP mass spectrometer installed at ISOLDE/CERN. Typically a resolving power of mΔm ≈ 1 × 106 was used and the mass determinations were assigned an accuracy of δmm ≈ 1 × 10−7. We show that with improvements to ISOLTRAP and refinements of the experimental technique an accuracy of δmm ≈ 3 × 10−8 can be obtained.
Nuclear physics with ion traps at ISOLDE: present and future
1993
Nuclear physics experiments with ion traps started at the on-line separator ISOLDE/CERN, Geneva, with the installation of the tandem Penning trap mass spectrometer ISOLTRAP. With this device the massM of a stored ion is determined by measuring its cyclotron frequency θc=(q/M)B in a magnetic fieldB. Mass measurements with a resolving powerR=θc/Δθc(FWHM)≈1×106 and accuracies of δM/M≈10−7 were performed on more than sixty unstable isotopes of the elements Rb, Sr, Cs, Ba, Fr, and Ra.
First absolute mass measurements of short-lived isotopes
1987
Absolute mass measurements of short-lived isotopes have been performed at the on-line mass separator ISOLDE at CERN by determining the cyclotron frequencies of ions confined in a Penning trap. The cyclotron frequencies for77,78,85,86,88Rb and88Sr ions could be determined with a resolving power of 3×105 and an accuracy of better than 10−6, which corresponds to 100 keV for massA=100. The shortest-lived isotope under investigation was77Rb with a half-life of 3.7 min. The resonances obtained for the isobars88Rb and88Sr were clearly resolved.
Measurement of the spin density matrix for the rho(0), K*(0)(892) and phi produced in Z(0) decays
1997
The spin density matrix elements for the rho(0), K-*0(892) and phi produced in hadronic Z(0) decays are measured in the DELPHI detector. There is no evidence for spin alignment of the K-*0(892) and phi, in the region x(p) less than or equal to 0.3 (x(p) = p/p(beam)), where rho(00) = 0.33 +/- 0.05 and rho(00) = 0.30 +/- 0.04, respectively. In the fragmentation region, x(p) greater than or equal to 0.4, there is some indication for spin alignment of the rho(0) and K-*0(892), since rho(00) = 0.43 +/- 0.05 and rho(00) = 0.46 +/- 0.08, respectively. These values are compared with those found in meson-induced hadronic reactions. For the phi, rho(00) = 0.30 +/- 0.04 for x(p) greater than or equal …
Photoproduction of light vector mesons in Xe–Xe ultraperipheral collisions at the LHC and the nuclear density of Xe-129
2018
We make predictions for cross sections of $\rho$ and $\phi$ vector meson photoproduction in ultraperipheral Xe-Xe collisions at $\sqrt{s_{NN}}=5.44$ TeV. Analyzing the momentum transfer distribution of $\rho$ mesons in this process, we explore the feasibility of extracting the nuclear density of $^{129}$Xe, which is needed in searches for dark matter with Xenon-based detectors.