122984783
Fusion suppression in mass-asymmetric reactions leading to Ra compound nuclei
Near-barrier excitation functions have been measured for evaporation-residue production and fission in the 12C + 204,206,208Pb and 48Ca + 168,170Er systems that lead to the compound nuclei 216,218,220Ra*. A Pronounced suppression of evaporation-residue production is observed for the more symmetric combinations, 48Ca + 168,170Er. We relate this to the significant quasifission components already observed for these systems.
123570790
Intruder configurations in neutron-rich P and S isotopes
Neutron-rich sdf-shell nuclei have attracted a great deal of international interest, both theoretically and experimentally. There is an increasing interest in using deep-inelastic reactions to obtain spectroscopic information about these exotic nuclei. New results obtained from two such experiments are presented here. The highly sensitive GASP array was used to measure the γ decays of previously unobserved yrast and near yrast states of 34P which were populated when 230 MeV 36S ions were incident on a thick target of 176Yb. In addition, a recent investigation of the spectroscopy of neutron-rich P and S isotopes has been undertaken with 215 MeV 36S ions incident on a thin target of 208Pb using the CLARA Ge detector array in conjunction with the PRISMA magnetic spectrometer. Preliminary results from this experiment are presented here.
27335793
Intruder negative-parity states of neutron-rich Si-33
This work was supported in part by the EPSRC (UK) and by the European Union under Contract No. RII3-CT-2004-506065. Five of us (D.O., M.B., A.H., K.K., and A.P.)acknowledge financial support from the EPSRC. Z.M.W acknowledges support from ORSAS and from the University of the West of Scotland. A.J. acknowledges financial supportfrom the Spanish Ministerio de Ciencia e Innovacion under Contract Nos. FPA2007-66069 and FPA2009-13377-C02-02. Zs.D. acknowledges the financial support from OTKA Project No. K68801.
124130898
Study of the neutron-rich nucleus Si-36
Excited states of N=22 Si-36, populated in deep-inelastic processes produced by the interaction of a 215 MeV beam of S-36 ions with a Pb-208 target, were studied in the present work. gamma rays from the binary fragments detected using CLARA, an array of 25 Ge Clover detectors, were measured in coincidence with projectile-like fragments detected by PRISMA, a large solid angle magnetic spectrometer. Two new gamma-ray photopeaks at energies of 1442 and 842 keV were observed and tentatively assigned to the 4(+)-> 2(+) and 6(+)-> 4(+) transitions, respectively. The systematics of the level structures of N=22 isotones are presented, and a comparison is made of the behavior of Si, Mg, and S isotopes. The level structure of Si-36 is also compared with the results of sdpf shell model calculations.
20604967
Dynamic effects during beam-based alignment
Complex beam-based alignment procedures are needed in future linear colliders to reduce the negative effects of static imperfections in the main linac on the beam emittance. The efficiency of these procedures could be affected by dynamic imperfections during their application. In this paper we study the resulting emittance growth.
54713754
Study of an ILC Main Linac that Follows the Earth Curvature
In the base line configuration, the tunnel of the ILC will follow the earth curvature. The emittance growth in a curved main linac has been studied including static and dynamic imperfections. These include effects due to current ripples in the power supplies of the steering coils and the impact of the beam position monitors scale errors.
55006506
STUDY OF FUNDAMENTAL MODE MULTIPOLAR KICKS IN DOUBLE- AND SINGLE-FEED POWER COUPLERS FOR THE CLIC MAIN LINAC ACCELERATING STRUCTURE
Multipolar kicks from the fundamental mode have been calculated in the CLIC baseline accelerating structure with double-feed input and output power couplers. The influence of such multipolar kicks on the main linac beam dynamics has been investigated. Furthermore, an alternative design of the couplers with single-feed has been studied and compared with the double-feed. Such an alternative would significantly simplify the waveguide system of the main linac but potentially introduce an harmful dipolar kick from the fundamental mode. The geometry of the coupler has been optimized in order to minimize such a dipolar kick and keep it below threshold levels determined with beam dynamics simulations. Influence of the higher order multipoles has been investigated as well and acceptable levels have been determined.
53956759
Effects of wake fields in the CLIC BDS
The wake fields due to collimators in the Beam Delivery System of CLIC are modeled using a conventional approach. According to the chosen ranges of parameters, differences in the transverse kicks due to both the geometric and resistive wall components for different regimes are highlighted (inductive or diffractive for the geometric wake fields, short- or long-range, ac or dc for the resistive wall wake fields). A module for particle tracking along the BDS including the effect of wake fields has been implemented in PLACET and first tracking results are shown.