DETECTOR DEVELOPMENT AND UPGRADE

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Detector development and upgrade Investigators: Schneider and Sweet Objectives The objectives stated in the recent renewal proposal are these: upgrade our two existing Area-Detector Systems Corp. (ADSC) Q315 detectors, initiate the purchase of a modern pixel-array detector (PAD) that is at the state of the art, contribute to and participate in a detector-development program (monolithic, highly-integrated modules). Although they were favorably reviewed, initially we did not receive funding for the last two projects. During this year the NCRR provided a supplement to fund the PAD detector; the detector-development project is still not funded. An additional objective added this year was to obtain a quicker and larger detector to replace the aging Q4r currently in use at X26-C. We managed to borrow a larger and faster one: a Q210 owned by the NSLS and previously at X6-A. Results  In summer 2009 we sent the second of our two Q315 detectors  the first one serial #3 from ADSC, purchased in 2002  for factory upgrades to Q315r specifications. It was equipped with new internal readout electronics and new thermo-electric coolers that now can keep the CCDs at the required low operating temperature. New image-gathering computers replaced obsolescent ones. When re-commissioned at X25, we confirmed that the gains in the standard 2x2 hardware binned readout mode met expectations. Including goniometry overhead we achieved a 0.8 second readout, down from the original 1.4 seconds. This compares well to typical exposure times of 1 sec or less at our undulator beamlines. Just as we were with the upgrade at X29, we are completely satisfied. In the fall of 2009 NCRR granted us a supplement that provided funding for acquisition of a pixel array detector (PAD). This will be used on our undulator beam line X25 to provide higher quality, faster data to users, Mail-in staff and clients. We issued a general Request for Proposal to ADSC, Rayonix (current manufacturers of what was the MAR detector series), and Dectris (Swiss firm manufacturing the Pilatus series of PADs). The request included a Performance specification to allow any technology to compete. We received an offer only from Dectris; the order was placed, confirmed, and agreed to in mid March 2010. This is a single-photon-counting, essentially noise-free detector. The expected performance specifications are in the table at the right. It will be about 80% efficient for 1¿ x-rays. Delivery is promised by mid February 2011. Plans  We will place the new detector at X25 where it will augment the mini-beam studies with its extremely low background performance. Significance  Once a pixel array detector becomes available on an NSLS undulator beamline, we will achieve dramatic gains in data quality and quantity beyond those possible with CCD-based detectors. Owing to the fast framing rate of 12 Hz, the astonishingly short readout dead-time of less than 4 ms, the complete discrimination against background to zero values, and the unitary point spread function, fine slicing data collection methods can be employed during a shutter-less continuous sweep of the crystal spindle. This entirely new method provides data-reduction and indexing programs with sharply defined, and narrowly boxed, Bragg spots over an unprecedented dynamic range, thus yielding more complete, crisper datasets at higher resolution, and ultimately better structures.