Brookhaven Accelerator Test Facility energy upgrade

Abstract

Brookhaven Accelerator Test Facility (ATF) is a laser linac complex, with a photocathode RF gun injection system and two sections of travelling wave linac. To satisfy the requirements of short wavelength free electron laser and laser acceleration experiments, ATF started an energy upgrade program with a goal of final energy on the order 100 MeV. Initial stage of the energy upgrade involves replace aged SLAC X-K5 klystron, and upgrade the magnets power supplies for the quadrupole magnets. A SLAC Energy Doubler (SLED) cavity will be installed in the second phase of the energy upgrade. Final stage of the project is to install another modulator and klystron so each section of the linac will be powered individually; which will allows us more flexibility to optimize the electron beam emittance compensation. We will also discuss issue of electron beam dynamics for operating the ATF at the higher energy.

Initial gain measurements of an 800nm SASE FEL, VISA

“…VISA has been commissioned and initial results have been obtained at the ATF [4] in BNL. The electron source is a 1.6 cell S-band photoinjector with an emittance compensating solenoid.…”

Experimental Studies of Transverse and Longitudinal Beam Dynamics in Photoinjector

“…Figure 1 shows the experimental arrangement. A 1.6-cell S-band (2856 MHz) rf gun, produced by Sumitomo Heavy Industries (SHI) as the Gun IV type at BNL, 12,14,15) was used in the experiment. The rf gun consisted of two cells: a half cell and a full cell.…”

“…In order to produce such electron beams, the technology of laser-driven photocathode rf guns (photoinjectors) has been studied. [8][9][10][11][12][13][14][15] The rf gun generates short electron bunches with short laser pulses. The electrons with a small energy spread and low space-charge-induced emittance are emitted from the photocathode surface with a strong rf electric field (!100 MV/m).…”

“…As a typical example, a 1.6-cell rf gun with a space-charge emittance compensation solenoid magnet has been developed in Brookhaven National Laboratory (BNL). 11,12) A transverse normalized rms emittance of 5.6 mmÁmrad with 1 nC of bunch charge was obtained in the rf gun with a 5 ps long Gaussian laser pulse. 16) However, emittance growth, due to the rf and the spacecharge effects, occurs in the rf gun.…”

Vibrating wire monitor: Versatile instrumentation for particle and photon beam measurements with wide dynamic range

“…In [8], different methods of profiling are compared. Scintillation YAG:Ce crystals of different thicknesses, an OTR screen, a phosphor screen, and a wire scanner (see also [19]) were used to measure the beam profile at the ATF photo-injector facility (a single-pulse photoelectron beam of 1 nC, with energy of 66 MeV). A significant sized blurring was observed on both YAG:Ce crystals and the phosphor screen compared to that on the OTR screen and wire scanner.…”