Development of ZnTe Powder Phosphor for Protein Crystallographic X-ray Detectors

Award Information
Agency: Department of Health and Human Services
Branch: N/A
Contract: 1R43GM076908-01
Agency Tracking Number: GM076908
Amount: $158,511.00
Phase: Phase I
Program: SBIR
Awards Year: 2006
Solicitation Year: 2006
Solicitation Topic Code: N/A
Solicitation Number: PHS2006-2
Small Business Information
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 (404) 664-5008
Business Contact
Phone: (404) 664-5008
Research Institution
DESCRIPTION (provided by applicant): We propose to develop a new phosphor for X-ray detectors used in protein crystallography, which can be used both in the home laboratory and at synchrotron beamlines. The phosphor, ZnTe:O, will be at least 3 times brighter than the conventional Gd2O2S:Tb currently used almost universally on such detector systems. ZnTe:O will also have a faster time response than Gd2O2S:Tb. ZnTe is chemically similar to ZnSe, with which PhosphorTech has already successfully developed an excellent phosphor, ZnSe:Cu,CI. ZnSe:Cu,CI is now a commercial product distributed by PhosphorTech. ZnSe:Cu,CI has been used for the past 6 years by Bruker AXS Inc. of Madison, Wl for its chemical crystallography CCD detectors. Bruker sells almost 90% of all chemical crystallography instruments in the USA and Europe, and our ZnSe phosphor has been an important reason for the success of their product, since it is well liked by Bruker customers. However, since it contains selenium, this phosphor is inappropriate for protein crystallography, in which selenium is the preferred element for anomalous dispersion phasing. The presence of an absorption anomaly at exactly the X-ray energy (12,658eV) used for phasing, would ruin these measurements. ZnTe will solve this problem, since the tellurium absorption anomalies are at different X-ray energies (4,341eV and 31,814eV). Theoretically ZnTe phosphors should be as bright, or brighter, than ZnSe phosphors. However, since tellurium is more chemically reactive than selenium, it is more difficult to work with. Thus our preliminary efforts to make a ZnTe:O phosphor have resulted in material that is initially very bright, but slowly oxidizes in the presence of water vapor, shortly after synthesis. During Phase I of this project, we will find methods to increase the inherent brightness of ZnTe:0, and to passivate and protect newly synthesized ZnTe:O powder, to prevent chemical deterioration of the material. We anticipate that in Phase II we will develop the means to produce commercial quantities of this stabilized powder, and fabricate large, high quality phosphor screens that can be used in commercial CCD detectors for protein crystallography.

* Information listed above is at the time of submission. *

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