Boris Podobedov

Photoinjected energy recovery linac upgrade for the National Synchrotron Light Source

We describe a major paradygm shift in in the approach to the production of synchrotron radiation This change will considerably improve the scientific capabilities of synchrotron light sources. We introduce plans for an upgrade of the National Synchrotron Light Source (NSLS). This upgrade will be based on the Photoinjected Energy Recovering Linac (PERL). This machine emerges from the union of two technologies, the laser-photocathode RF gun (photoinjector) and superconducting linear accelerators with beam energy recovery (Energy Recovering Linac). The upgrade will bring the NSLS users many new insertion device beam lines, brightness greater than 3rd generation light-sources and ultra-short pulse capabilities, not possible with storage ring light sources.

NSLS upgrade concept

To address the growing needs of the NSLS user community we are aggressively pursuing R&D towards a facility upgrade. The present goals are a 3 GeV ultra-low emittance storage ring, tailored to the 5-20 keV photon energy range, that will triple the present NSLS ID capacity, and provide three orders of magnitude increase in brightness over the present brightest NSLS beamlines. To achieve these goals we propose a 24 period TBA lattice, with extensive use of super-conducting small gap undulators. This paper reviews our preliminary design and the key accelerator physics issues.

Longitudinal density modulation of unstable bunches emitting coherent IR

Observations of coherent infrared (IR) light emissions from /spl sim/30 cm long electron bunches at the NSLS VUV ring have been reported. The emissions occurred above some current threshold and had a maximum spectral content near 42 GHz, leading to speculations that they were due to a longitudinal instability creating a /spl sim/7 mm modulation of the bunch density. To check this experimentally we performed streak camera measurements recording a large number of beam profiles taken both during and between the coherent emission bursts. In the course of our studies we have directly proven that the longitudinal beam density indeed experiences a significant modulation when coherent emission bursts occur.

NSLS II: The Future of the NSLS

The National Synchrotron Light Source at BNL was the first dedicated light source facility and it has now operated for more than 20 years. During this time the user community has grown to more than 2400 users annually. To insure that this vibrant user community has access to the highest quality photon beams, the NSLS is pursuing the design of a new ultra-high brightness (∼1021) electron storage ring, tailored to the 0.3-20 KeV photon energy range. We present our preliminary design and review the critical accelerator physics design issues.

NSLS-II Injection Concept

Currently the facility upgrade project is in progress at the NSLS (at Brookhaven National Laboratory). The goal of the NSLS-II is a 3 GeV ultra-low-emittance storage ring that will increase radiation brightness by three orders of magnitude over that of the present NSLS X-ray ring. The low emittance of the high brightness ring’s lattice results in a short lifetime, so that a top-off injection mode becomes an operational necessity. Therefore, the NSLS-II injection system must provide, and efficiently inject, an electron beam at a high repetition rate. In this paper, we present our concept of the NSLS-II injection system and discuss the conditions for, and constraints on, its design.

Harmonic Cavity Performance for NSLS-II

NSLS-II is a 3 GeV ultra-high brightness storage ring planned to succeed the present NSLS rings at BNL. Ultra-low emittance combined with short bunch length means that it is critical to minimize the effects of Touschek scattering and coherent instabilities. Improved lifetime and stability can be achieved by including a third-harmonic RF cavity in the baseline design. This paper describes the required harmonic RF parameters and the expected system performance.

A SCRF linac as a FEL driver and storage ring injector

A 5 GeV superconducting radiofrequency (SCRF) linac for the dual application of FEL driver and top-off injector for a storage ring is described. Starting from the FEL drive beam requirements of subpicosecond bunch lengths and kiloamp peak current the choice of frequency, gradient and operating modes of the linac are presented. Magnetic optics and RF system descriptions follow to provide the specified beam parameters. Accelerator design issues are identified for future studies.

Beam position monitor gate functionality implementation and applications

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