J. -P. Carneiro

The Side-Coupled Linac (SCL) section of the FNAL linac accelerates the beam from 117 MeV to 401.5 MeV, operating at 22-24 mA beam current. Transverse focusing is performed by 32 quadrupoles, and the beam orbit is guided by 19 dipole correctors and measured by 29 BPMs. The bunch length is measured in a single location by a Bunch Shape Monitor (BSM). This paper presents a three-step reconstruction of the machine optics. First, the transverse and longitudinal Twiss parameters at the start of the SCL section are determined using quadrupole scans and BSM measurements at different settings of an upstream cavity. Second, the quadrupole calibrations are adjusted based on differential-trajectory measurements. Finally, the beam is propagated along the SCL linac using the code TraceWin. A comparison between TraceWin simulations and the beam envelope measured by the 12 wire scanners of the SCL linac was performed. Transverse and longitudinal beam parameters at the entrance of the transition section will be reported.

This paper presents measurements of the beam transmission performed on the 4-rod RFQ currently under operation at Fermilab. The beam current has been measured at the RFQ exit as a function of the magnetic field strength in the two LEBT solenoids. This measurement is compared with scans performed on the FermiGrid with the beam dynamics code TRACK. A particular attention is given to the impact, on the RFQ beam transmission, of the space-charge neutralization in the LEBT.

The ability to produce high brightness electron beams as required for modern Free Electron Lasers (FELs) has been demonstrated during the first stage of the Photo Injector Test Facility at DESY Zeuthen (PITZ1). The electron source optimization at PITZ1 was successfully completed, resulting in the installation of the PITZ rf gun at the VUV-FEL (DESY, Hamburg). One of the main goals of the second stage of PITZ (PITZ2) is to apply higher gradients in the rf gun cavity in order to obtain smaller beam emittance by faster acceleration of the space charge dominated beams. In order to reach the required gradients a 10 MW klystron has to be installed and the gun cavity has to be conditioned for higher peak power. Another important goal of PITZ2 is a detailed study of the emittance conservation principle by using proper electron beam acceleration with a booster. Further photo injector optimization, including update of the photocathode laser and diagnostic tools, is foreseen as well. Recent progress on the PITZ developments will be reported.

A digital beam phase monitor has been installed on the TEVATRON ring. This device will be mainly use to diagnose the energy oscillations of each of the 36 × 36 proton and antiproton bunches as well as to study the transient beam loading. The first results obtained from the beam phase monitor is presented on the paper.

The Fermilab photoinjector produces electron bunches of 1–12 nC charge with an energy of 16–18 MeV. Detailed measurements and optimization of the transverse emittance have been carried out for a number of beam line optics conditions, and at a number of beam line locations. The length of the bunches has also been measured, first for an uncompressed beam (as a function of the charge) and then for a compressed beam of 8 nC charge (as a function of the 9-cell cavity phase). These measurements are presented and compared with the simulation codes HOMDYN and ASTRA.

An RF photo-injector was installed at Fermilab between January and June 97. The photo-injector produced its first beam on 4 June 97. This report provides a brief description of the accelerator and a summary of the experiments carried out through December '97.