Overview of the X25 Upgrade Project and Funding History

At the start of 2004, beamline X25's programmatic focus shifted completely to monochromatic macromolecular crystallography, following 14 years of operation as a mixed-use high-brightness beamline. Thus NSLS has been presented with an opportunity to renovate the beamline, as well as the radiation source, to optimize them for a dedicated macromolecular crystallography program. To this end, the BNL Macromolecular Crystallography Research Resource (PXRR), a collaboration of the BNL Biology Dept. and NSLS, submitted a funding request in late 2002 as part of its proposal to NIH NCRR and DOE BER to renew its 5-year grant. It was well received, and $2.2M in funds were awarded by DOE BER beginning in late 2003, to be dispensed over the course of 3 fiscal years. During the December 2005 shutdown, the existing hybrid wiggler, which has served as the radiation source for beamline X25 since its inception in 1990, was replaced by a custom-designed in-vacuum miniature gap hybrid undulator. The new radiation source will be 15 times brighter than the present one at 6.3 keV, and 6 times brighter at 10.5 keV. Its design consists of 0.99 m long planar hybrid magnet arrays with a period length of 18 mm (55 periods total) and minimum attainable gap of 5.6 mm, with corresponding maximum K of 1.5. It will also incorporate provision for cryogenic operation (in order to attain an even higher K), which might be pursued in the future. Unlike previous miniature gap undulator designs in use at NSLS, the one to be implemented for X25 will be continuously tunable from 2 to 20 keV, by employing all harmonics up through the 9th. The undulator vacuum and gap separation system is now under manufacture by Advanced Design Consulting of Lansing, NY. In conjunction with the new radiation source, upgrades to the beamline optics will be implemented, in order to exploit the properties of the new source. The current double crystal monochromator will be replaced by one which incorporates cryogenic cooling of the first crystal and sagittal bending of the second crystal to permit horizontal focusing. It will be followed by a new bendable mirror, containing multiple coating stripes, to permit vertical focusing.

BES

BER

NCRR

Updated 29 Dec 2005	Security Notice   Webteam   Site Map   Bio   PXRR   NSLS   BNL