An overview of recent improvements in our understanding of, and the maturity of, linear-mode photon counting with the HgCdTe electron-initiated avalanche photodiode is presented. In 2010 DRS fabricated an experimental 2 9 8 array with (64 lm) 2 pixels which enabled, for the first time, linear-mode photon counting by use of the MWIR cutoff HgCdTe electron-initiated avalanche photodiode. The device had a high single-photon signal-to-noise ratio of 13.7, an excess noise factor of 1.3-1.4, a 7 ns minimum time between events, and a broad spectral response extending from 0.4 lm to 4.2 lm. DRS recently fabricated a new set of devices with improved yield and performance compared with the first device: the false event rate was reduced by a factor of almost 10 to 150 kHz, the photon detection efficiency was increased from 50% to >60%, and the APD gain was increased by a factor of 4 to over 1900.

Students' competency is a critical concern in health sciences education. Therefore, work-integrated learning has become an integral part of health sciences programmes at higher education institutions. This study explored students' views and experiences of clinical observational learning to promote work-integrated learning in the acupuncture programme at a South African university. The authors used the Technological, Pedagogical, and Content Knowledge (TPACK) model as a theoretical lens to guide this study, involving five participants who were purposively selected. A qualitative descriptive single case study design was employed within an interpretivist paradigm. Five participants were recruited for this study. The authors employed semi-structured interviews as the data collection instrument. The data were analysed using the six-step thematic analysis. The findings revealed that students agreed that clinical observational learning significantly improved clinical competency. They reported that clinical observational learning assisted them in memorising content knowledge and obtaining practical experience. Furthermore, participants highlighted that a lack of space, insufficient time, and incompetency of observed student practitioners negatively affected their learning experience. This study concluded that higher education institutions should employ clinical observational learning in the curriculum to assist in transitioning students from theoretical knowledge to clinical practice. It is recommended that further research must be conducted at national and international higher education institutions.

Results of characterization data on linear mode photon counting (LMPC) HgCdTe electroninitiated avalanche photodiode (e-APD) focal plane arrays (FPA) are presented that reveal an improved understanding and the growing maturity of the technology. The first successful 2x8 LMPC FPA was fabricated in 2010 [1]. Since then a process validation lot of 2x8 arrays was fabricated. Five arrays from this lot were characterized that replicated the previous 2x8 LMPC array performance. In addition, it was unambiguously verified that readout integrated circuit (ROIC) glow was responsible for most of the false event rate (FER) of the 2010 array. The application of a single layer metal blocking layer between the ROIC and the detector array and optimization of the ROIC biases reduced the FER by an order of magnitude. Photon detection efficiencies (PDEs) of greater than 50% were routinely demonstrated across 5 arrays, with one array reaching a PDE of 70%. High resolution pixel-surface spot scans were performed and the junction diameters of the diodes were measured. The junction diameter was decreased from 31 µm to 25 µm resulting in a 2x increase in E-APD gain from 470 on the 2010 array to 1100 on one of the 2013 FPAs. Mean single photon signal to noise ratios of >12 were demonstrated at excess noise factors of 1.2-1.3. NASA Goddard Space Flight Center (GSFC) performed measurements on the delivered FPA that verified the PDE and FER data.

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