SBIR-STTR Award

It has been demonstrated that multilayer analyzer array detector is advantageous in x-ray fluorescence detection under high flux and dilute metal conditions. With a good rejection rate, about 25 times, and reasonably large solid angle, sub-millimolar concentration can be routinely accessed. However, the performance of the detector is still lagging behind the photon flux and brightness increases at the third or even fourth generation synchrotron sources. With more than 100 to 1000 flux increases at the third generation source, these sources would permit detection of metal concentration in the order of 10 micro-Molar or several ppm range. This will allow the monitoring of some biologically relevant metals in vivo. Thus we propose to develop x-ray fluorescence detector using synthetic multilayer pairs. With two-stage rejection of primary and secondary multilayers, it is anticipated that the rejection rate will exceed 200 times. With a 20 percent throughput, the anticipated gain on the effective count rate can be as high as 40 times on dilute systems. Initial evaluation shows that the detector can be made tunable in a wide energy region and to cover a large solid angle. The major goal for the Phase I project is to design and fabricate a prototype multilayer pair detector. The test and evaluation of the detector performance will aid in the design of a multilayer pair analyzer array detector. Phase II project will develop such a detector to a product. PROPOSED COMMERCIAL APPLICATION: The need for a very sensitive and high count rate x-ray fluorescence detector is well justified. The instrument will be vital to x-ray spectroscopy and micro fluorescence imaging on biological systems under high flux and dilute situations. With ever increasing photon flux at the new synchrotron sources, the detector will have a better market potential than fluorescence ionization chambers and the solid state detectors which are currently available.

It has been repeatedly emphasized in the BioSync Report that the development of better XAS detector systems is critical in solving the problem of detectors lagging behind synchrotron sources. The detector bottleneck encountered is in two areas: one is detector count rate limitation, and the other is its limited rejection rate of background in order to examine very dilute systems. By the development of the multilayer analyzer array detector (MAAD), we effectively increased the count rate, and therefore the efficiency of fluorescence detection. Now, we are proposing to largely increase the rejection rate by developing muitilayer analyzer pair array detectors (MAPAD). Our Phase I project has shown that such a detector can be made with a high rejection rate and a reasonable throughput. With two-stage rejection of primary and secondary multilayers, the rejection rate will exceed 200 times with a 15 to 20% throughput. With 28 double multilayer pairs, the detector will collect close to 2% total solid angle at 6 KeV. The anticipated gain on the effective photon counts will be as high as 40 times on very dilute systems. The detector can be made tunable in a large energy region, and easy to operate. With a flexible design, the detector can perform the pair rejection as well as the single multilayer rejection, just like a MAAD. Thus the detector can cover a large sample dilution range from a few mM down to 20 microM or a few ppm. For trace metal detection, the approachable concentration can go even lower. This kind of sensitivity should enable us to approach new systems, such as the examination of biological relevant metals in vivo as well as very dilute systems in environmental, material, physical and chemical research. The detector has a very good market potential benefiting efficient use of high flux beamlines. By expanding the XAS technique to new systems, the detector can potentially enter into new markets.

Thesaurus Terms:
X ray spectrometry, biomedical equipment development, monitoring device, radiofluorescent probe biosensor, metal bioengineering /biomedical engineering