TY - GEN
T1 - Multilayered superconducting tunnel junctions for use as high-energy-resolution x-ray detectors
AU - Rippert, Edward D.
AU - Song, Shenian N.
AU - Ketterson, John B.
AU - Ulmer, Melville P.
N1 - Funding Information:
This research is funded in part by the National Science Foundation's Science and Technology Center for High Temperature Superconductivity under contract NSFIDMR-8809854.
Publisher Copyright:
© 1991 SPIE.
PY - 1991/10/1
Y1 - 1991/10/1
N2 - X-ray detectors based on superconducting tunnel junction technology are desirable due to their potential for higher energy resolution and greater charge carrier production than conventional semiconductor devices. Single junction devices fabricated by thermal or plasma oxidation of elemental, soft metal, superconductors have shown some promise, but tend to suffer from poor opacity, performance degradation upon thermal recycling, and unequal total charge collected for absorption of x rays in different layers due to differing tunneling characteristics of each layer. More complex designs, such as quasi-particle trapping systems and all refractory materials, can help with the unequal charge and thermal cycling problems, respectively. However, new problems in complexity of fabrication and short quasi-particle lifetimes arise. Other potential difficulties include resolution degradation due to trapping of quasi-particles at the photoabsorption site or near defects and tolerance of the devices to faults induced by their environment. The use of multilayers of superconducting tunnel junctions, consisting of tens to hundreds of identical tunnel junctions stacked on top of one another, as a design can address these problems. The multilayer can, in principle, be made as thick as desired in order to increase opacity, while the individual superconducting layers can be made very thin in order that the tunneling time of the quasi-particles be short compared with the quasi-particle lifetime for even refractory superconductors. In addition, the layer thinness helps to alleviate undesirable quasi-particle trapping. The inherent redundancy of junctions in a multilayered device allows for continued operation even after multiple single layer failures. The unique physical and technological possibilities of multilayered devices, such as resonant tunneling and built in preamplification, make them structures worthy of study even without the more pragmatic inducements described above.
AB - X-ray detectors based on superconducting tunnel junction technology are desirable due to their potential for higher energy resolution and greater charge carrier production than conventional semiconductor devices. Single junction devices fabricated by thermal or plasma oxidation of elemental, soft metal, superconductors have shown some promise, but tend to suffer from poor opacity, performance degradation upon thermal recycling, and unequal total charge collected for absorption of x rays in different layers due to differing tunneling characteristics of each layer. More complex designs, such as quasi-particle trapping systems and all refractory materials, can help with the unequal charge and thermal cycling problems, respectively. However, new problems in complexity of fabrication and short quasi-particle lifetimes arise. Other potential difficulties include resolution degradation due to trapping of quasi-particles at the photoabsorption site or near defects and tolerance of the devices to faults induced by their environment. The use of multilayers of superconducting tunnel junctions, consisting of tens to hundreds of identical tunnel junctions stacked on top of one another, as a design can address these problems. The multilayer can, in principle, be made as thick as desired in order to increase opacity, while the individual superconducting layers can be made very thin in order that the tunneling time of the quasi-particles be short compared with the quasi-particle lifetime for even refractory superconductors. In addition, the layer thinness helps to alleviate undesirable quasi-particle trapping. The inherent redundancy of junctions in a multilayered device allows for continued operation even after multiple single layer failures. The unique physical and technological possibilities of multilayered devices, such as resonant tunneling and built in preamplification, make them structures worthy of study even without the more pragmatic inducements described above.
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U2 - 10.1117/12.48346
DO - 10.1117/12.48346
M3 - Conference contribution
AN - SCOPUS:33747686844
T3 - Proceedings of SPIE - The International Society for Optical Engineering
SP - 283
EP - 288
BT - EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy II
A2 - Siegmund, Oswald H. W.
A2 - Rothschild, Richard E.
PB - SPIE
T2 - EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy II
Y2 - 21 July 1991 through 21 July 1991
ER -