[en] Six cases of large defects of the scalp, skull, and dura following tumor ablation and radiation are presented. Each was accompanied by chronic infection in the irradiated defect. Efforts to reconstruct the resulting defects with local flaps were not successful. One-stage reconstruction was then accomplished in each case utilizing a latissimus dorsi musculocutaneous or myo-osteocutaneous free flap transferred by microvascular anastomoses. The versatility of the latissimus dorsi musculocutaneous and/or osseous flap allows single-stage reconstruction of these complex defects

[en] We are developing superconducting transition-edge sensor (TES) microcalorimeters that are optimized for rapid isotopic analysis of trace actinide samples by Q-spectroscopy. By designing mechanically robust TESs and simplified detector assembly methods, we have developed a detector for Q-spectroscopy of actinides that can be assembled in minutes. We have characterized the effects of each simplification and present the results. Finally, we show results of isotopic analysis of plutonium samples with Q-spectroscopy detectors and compare the results to mass spectrometry

[en] The application of cryogenic microcalorimeter detectors to γ-ray spectroscopy allows for measurements with unprecedented energy resolution. These detectors are ideally suited for γ-ray spectroscopy applications for which the measurement quality is limited by the spectral overlap of many closely spaced transitions using conventional detector technologies. The non-destructive analysis of mixed-isotope Pu materials is one such application where the precision can be potentially improved utilizing microcalorimeter detectors compared to current state-of-the-art high-purity Ge detectors (HPGe). The LANL-NIST γ-ray spectrometer, a 256-pixel microcalorimeter array based on transition-edge sensors (TESs), was recently commissioned and used to collect data on a variety of Pu isotopic standards to characterize the instrument performance. These measurements represent the first time the simultaneous readout of all 256 pixels for measurements of mixed-isotope Pu materials has been achieved. The LANL-NIST γ-ray spectrometer has demonstrated an average pixel resolution of 55 eV full-width-at-half-maximum at 100 keV, nearly an order of magnitude better than HPGe detectors. Some challenges of the analysis of many-channel ultra-high resolution data and the techniques used to produce quality spectra for isotopic analysis will be presented. The LANL-NIST γ-ray spectrometer has also demonstrated stable operation and obtained high resolution measurements at total array event rates beyond 1 kHz. For a total event rate of 1.25 kHz, approximately 5.6 cps/pixel, a 72.2 eV average FWHM for the 103 keV photopeak of ¹⁵³Gd was achieved

[en] Normal metal-insulator-superconductor tunnel junctions are candidates for large-format arrays of ultra-low noise equivalent power bolometers. Using a wafer scale process we have fabricated devices with the required sub μm³ volumes and ohmic superconductor-normal metal contacts for delivering power loads. Additionally, we demonstrate simultaneous tunnel junction thermometry and SQUID-based Johnson current noise thermometry

[en] Solid-state refrigerators based on normal metal/insulator/superconductor (NIS) tunnel junctions are now a practical means of cooling from pumped ³He bath temperatures to near 100 mK. While integration of NIS refrigerators with transition-edge sensors is underway, a more general-purpose cooling platform is desirable. We report on progress developing a NIS refrigerator designed to cool microelectronics devices on separate chips

[en] We describe progress in the development of a close-packed array of bolometers designed for use in photometric applications at millimeter wavelengths from ground-based telescopes. Each bolometer in the array will use a proximity-effect Transition Edge Sensor (TES) sensing element and each will have integrated Normal-Insulator-Superconductor (NIS) refrigerators to cool the bolometer below the thermal reservoir temperature. The NIS refrigerators and acoustic-phonon-mode-isolated bolometers are fabricated on silicon. The radiation absorbing element is mechanically suspended by four legs, whose dimensions are used to control and optimize the thermal conductance of the bolometer. Using the technology developed at NIST, we fabricate NIS refrigerators at the base of each of the suspension legs. The NIS refrigerators remove hot electrons by quantum-mechanical tunneling and are expected to cool the biased (10pW) bolometers to <170mK while the bolometers are inside a pumped ³He-cooled cryostat operating at ∼280mK. This significantly lower temperature at the bolometer allows the detectors to approach background-limited performance despite the simple cryogenic system

[en] We report on the development of a SQUID multiplexer operated at microwave frequencies. This multiplexer can accommodate any detector that can be read out with SQUIDs, including transition-edge sensors, magnetic calorimeters, and superconductor-insulator-superconductor tunnel junction detectors. The total bandwidth, which is set by the HEMT amplifier, can be as high as 5GHz, allowing the readout of 10³-10⁴ low-bandwidth detectors into one coaxial cable. Alternatively, in a low-Q circuit each SQUID can have a bandwidth as high as 100-200MHz, allowing multiplexing of high-bandwidth sensors, such as optical TES photon detectors and antenna-coupled hot-electron TES bolometers. Each SQUID must be flux biased at a sensitive point on its response curve. We describe a multiplexed flux biasing scheme that makes it possible to flux bias a large array of SQUIDs with only one additional coaxial cable. We further present a hybrid 'TDMA' multiplexer optimized for the high dynamic range and slew rate of fast X-ray calorimeters

[en] We will measure kaonic helium x-rays using transition-edge-sensor microcalorimeters, TES, in the J-PARC hadron experimental facility. To demonstrate the feasibility of the experiment, we performed a measurement of pionic carbon x-rays at PSI, where an excellent FWHM energy resolution of 7 eV at 6.4 keV was achieved. We also evaluated the expected TES performance in the kaon beam at J-PARC. The simulation results show that the TES spectrometer would work with a good energy resolution, and clear peaks of kaonic helium x-rays would be observed on a reasonably suppressed background. (author)