arXiv subjects

S. Lidia

Publications and source records attributed to S. Lidia.

4 recordsLinked to original sources

arXiv2014

Accessing defect dynamics using intense, nanosecond pulsed ion beams

Gaining in-situ access to relaxation dynamics of radiation induced defects will lead to a better understanding of materials and is important for the verification of theoretical models and simulations. We show preliminary results from experiments at the new Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory that will enable in-situ access to defect dynamics through pump-probe experiments. Here, the unique capabilities of the NDCX-II accelerator to generate intense, nanosecond pulsed ion beams are utilized. Preliminary data of channeling experiments using lithium and potassium ions and silicon membranes are shown. We compare these data to simulation results using Crystal Trim. Furthermore, we discuss the improvements to the accelerator to higher performance levels and the new diagnostics tools that are being incorporated.

cond-mat.mtrl-sci↗

arXiv2004

Generation of angular-momentum-dominated electron beams from a photoinjector

Various projects under study require an angular-momentum-dominated electron beam generated by a photoinjector. Some of the proposals directly use the angular-momentum-dominated beams (e.g. electron cooling of heavy ions), while others require the beam to be transformed into a flat beam (e.g. possible electron injectors for light sources and linear colliders). In this paper, we report our experimental study of an angular-momentum-dominated beam produced in a photoinjector, addressing the dependencies of angular momentum on initial conditions. We also briefly discuss the removal of angular momentum. The results of the experiment, carried out at the Fermilab/NICADD Photoinjector Laboratory, are found to be in good agreement with theoretical and numerical models.

physics.acc-ph↗

arXiv2000

Analysis of longitudinal bunching inan FEL driven two-beam accelerator

Recent experiments [1] have explored the use of a free-electron laser (FEL) as a buncher for a microwave two-beam accelerator, and the subsequent driving of a standing-wave rf output cavity. Here we present a deeper analysis of the longitudinal dynamics of the electron bunches as they are transported from the end of the FEL and through the output cavity. In particular, we examine the effect of the transport region and cavity aperture to filter the bunched portion of the beam. [1] T. Lefevre, et. al., Phys. Rev. Lett. 84 (2000), 1188.

physics.acc-ph↗

arXiv2000

The RTA Betatron-Node Experiment: Limiting Cumulative BBU Growth In A Linear Periodic System

The successful operation of a Two-Beam accelerator based on extended relativistic klystrons hinges upon decreasing the cumulative dipole BBU growth from an exponential to a more manageable linear growth rate. We describe the theoretical scheme to achieve this, and a new experiment to test this concept. The experiment utilizes a 1-MeV, 600-Amp, 200-ns electron beam and a short beamline of periodically-spaced rf dipole-mode pillbox cavities and solenoid magnets for transport. Descriptions of the beamline are presented, followed by theoretical studies of the beam transport and dipole-mode growth.

physics.acc-ph↗