The High Current Experiment (HCX) at Lawrence Berkeley National Laboratory is part of the US program that explores heavy-ion beam as the driver option for fusion energy production in an Inertial Fusion Energy (IFE) plant. The HCX is a beam transport experiment at a scale representative of the low-energy end of an induction linear accelerator driver. The primary mission of this experiment is to investigate aperture fill factors acceptable for the transport of space-charge-dominated heavy-ion beams at high intensity (line charge density {approx}0.2 {micro}C/m) over long pulse durations (4 {micro}s) in alternating gradient focusing lattices of electrostatic or magnetic quadrupoles. This experiment is testing transport issues resulting from nonlinear space-charge effects and collective modes, beam centroid alignment and steering, envelope matching, image charges and focusing field nonlinearities, halo and, electron and gas cloud effects. We present the results for a coasting 1 MeV K{sup +} ion beam transported through ten electrostatic quadrupoles. The measurements cover two different fill factor studies (60% and 80% of the clear aperture radius) for which the transverse phase-space of the beam was characterized in detail, along with beam energy measurements and the first halo measurements. Electrostatic quadrupole transport at high beam fill factor ({approx}80%) ismore » achieved with acceptable emittance growth and beam loss. We achieved good envelope control, and re-matching may only be needed every ten lattice periods (at 80% fill factor) in a longer lattice of similar design. We also show that understanding and controlling the time dependence of the envelope parameters is critical to achieving high fill factors, notably because of the injector and matching section dynamics.« less

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Parametic Study of the current limit within a single driver-scaletransport beam line of an induction Linac for Heavy Ion Fusion

A report on the challenges confronting the Fermilab Linac and Booster accelerators is presented. Plans to face those challenges are discussed. Historically, the Linac/Booster system has served only as an injector for the relatively low repetition rate Main Ring synchrotron. With construction of an 8 GeV target station for the 5 Hz MiniBooNE neutrino beam and requirements for rapid multi-batch injection into the Main Injector for the NUMI/MINOS experiment, the demand for 8 GeV protons will increase more than an order of magnitude above recent high levels. To meet this challenge, enhanced ion source performance, better Booster orbit control, a beam loss collimation/localization system, and improved diagnostics are among the items being pursued. Booster beam loss reduction and control are key to the entire near future Fermilab high energy physics program.

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Challenges to the Fermilab linac and Booster accelerators

This paper is a summary report of the Proton Driver design study that has recently been completed at Fermilab. It describes the design of a new 16 GeV high intensity rapid cycling synchrotron as a replacement of the present Booster. The major design goals are: (1) 1 MW beam power; (2) 1 ns (r.m.s.) bunch length. The construction will be staged. It has also an upgrade path to 4 MW.

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Summary of the Fermilab proton driver design study

Improvements in the Fermilab operating 400-MeV linear accelerator injector are required to achieve the beam intensity and emittance requirement of the Proton Driver design study. It has been determined that these requirements can be achieved by replacing the components in the linac below 10 MeV. An improved H/sup -/ ion source with an electrostatic transport to a two-section radio-frequency quadrupole (RFQ) accelerator, with the RFQ sections separated by a magnetic five-dimensional phase-space imaging system as used in an earlier Fermilab/SAIC PET Project, and a new 10-MeV drift-tube linac cavity have been studied. It appears possible that an H/sup -/ intensity of 4.5/spl times/10/sup 13/ ions per pulse with an improvement in beam emittance from the present system can be achieved with the proposed changes.

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C.W. Schmidt

Papers

Low energy improvements to the Fermilab 400-MeV linear accelerator