Author: Todd, D.S.
Paper Title Page
MO2PB02 High Current Beam Extraction from the 88-Inch Cyclotron at LBNL 19
  • D.S. Todd, J.Y. Benitez, K.Y. Franzen, M. Kireeff Covo, C.M. Lyneis, L. Phair, P. Pipersky, M.M. Strohmeier
    LBNL, Berkeley, California, USA
  The low energy beam transport system and the inflector of the 88-Inch Cyclotron have been improved to provide more intense heavy-ion beams, especially for experiments requiring 48Ca beams. In addition to a new spiral inflector* and increased injection voltage, the injection line beam transport and beam orbit dynamics in the cyclotron have been analyzed, new diagnostics have been developed, and extensive measurements have been performed to improve the transmission efficiency. By coupling diagnostics, such as emittance scanners in the injection line and a radially-adjustable beam viewing scintillator within the cyclotron, with computer simulation we have been able to identify loss mechanisms. The diagnostics used and their findings will be presented. We will discuss the solutions we have employed to address losses, such as changing our approach to tuning VENUS and running the cyclotron's central trim coil asymmetrically.
*Ken Yoshiki Franzen, et al. "A center region upgrade of the LBNL 88-Inch Cyclotron", these proceedings
slides icon Slides MO2PB02 [0.824 MB]  
TUPPT015 A Center Region Upgrade of the LBNL 88-Inch Cyclotron 186
  • K. Yoshiki Franzen, J.Y. Benitez, M.K. Covo, A. Hodgkinson, C.M. Lyneis, B. Ninemire, L. Phair, P. Pipersky, M.M. Strohmeier, D.S. Todd
    LBNL, Berkeley, California, USA
  • D. Leitner
    NSCL, East Lansing, Michigan, USA
  This paper describes the design and results of an upgraded cyclotron center region in which a mirror field type inflector was replaced by a spiral inflector. The main goals of the design were a) to facilitate injection at higher energies in order to improve transmission efficiency and b) to reduce down-time due to the need of replacing mirror inflector wires which rapidly break when exposed to high beam currents. The design was based on a detailed model of the spiral inflector and matching center region electrodes using AMaze, a 3D finite element suite of codes. Tests showed promising results indicating that the 88-Inch cyclotron will be able to provide a 2.0 pμA beam of 250 MeV 48Ca ions.  
TUPSH016 Trim Coil Unbalance of the 88-Inch Cyclotron 254
  • M. Kireeff Covo, B. Bingham, C.M. Lyneis, B. Ninemire, L. Phair, P. Pipersky, A. Ratti, M.M. Strohmeier, D.S. Todd
    LBNL, Berkeley, California, USA
  • K.Y. Franzen
    Mevion, Littleton, Massachusetts, USA
  Funding: Work supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Nuclear Physics Division of the U.S. Department of Energy under Contract DE-AC02-05CH11231.
The 88-inch cyclotron Dee probe shows large losses inside the radius of 20 cm and suggests problems in the ion beam injection. The current of the top and bottom innermost trim coil 1 is unbalanced to study effects of the axial injection displacement. A new beam profile monitor images the ion beam bunches, turn by turn, and the beam center of mass position is measured. The technique allows increasing the beam transmission through the cyclotron.
TU3PB02 Development of a Scintillator Probe Based on Fiber Optics for Radial Beam Diagnostics of the Ion Beam of the 88-Inch Cyclotron 262
  • M.M. Strohmeier, J.Y. Benitez, M.K. Covo, C.M. Lyneis, B. Ninemire, L. Phair, P. Pipersky, D.S. Todd
    LBNL, Berkeley, California, USA
  • K.Y. Franzen
    Mevion, Littleton, Massachusetts, USA
  Operators at the 88-Inch Cyclotron have many tuning parameters to optimize transmission from injection through extraction. However, the only diagnostics they have had were a Faraday Cup at the exit of the machine and a so called "Dee-Probe" which gives a current-vs-radius (IvR) measurement. Motivated by low transmission of the Cyclotron and to address how tuning can affect the beam, we have developed an optical beam viewer whose radial position within the cyclotron can be adjusted remotely. This viewer allows us to image the beam cross section and its axial position with very high spatial resolution as a function of radius. In this paper, we describe the mechanical development of the device which consists of a Kbr scintillator crystal, a fiber bundle and a digital camera and we present data from its initial commissioning.  
slides icon Slides TU3PB02 [4.936 MB]