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In the last years, custom-technology single-photon avalanche diodes (SPADs) have demonstrated remarkable performance, thanks to the fine engineering process performed on the electric field profile. However, the integration of custom SPADs in detector arrays often conflicts with the low-threshold current sensing that is mandatory to extract the timing information. A new custom-technology SPAD is introduced, that exploits an extra epitaxial layer in order to reduce the capacitive coupling between the anode and the chip substrate. The new detector shows a state-of-the-art timing jitter of 34 ps full width at half maximum and a weak dependence on the detection threshold, even when the substrate is kept at a fixed voltage, as required by the implementation of multichannel photon timing systems. [ABSTRACT FROM AUTHOR]

Excellent performance of custom technology SPAD detectors have been widely demonstrated in recent years. Low‐jitter timing measurements with these detectors require front end electronics able to sense the avalanche current at a very low level when the multiplication process is still confined in a very small area around the photon absorption point. Best in class results (35 ps full width at half maximum) have been obtained with discrete circuits not suitable to be used in densely integrated systems of SPAD arrays required by modern demanding applications. A new fully integrated front end able to read out the avalanche current with a timing jitter as low as 32 ps and suitable to be exploited with SPAD arrays is presented. [ABSTRACT FROM AUTHOR]

To describe sonographic features of the microcystic elongated and fragmented (MELF) pattern of myometrial invasion (MI) using the International Endometrial Tumor Analysis (IETA) criteria; to assess the effect of the MELF pattern on preoperative ultrasound evaluation of MI; and to determine the relationship of the MELF pattern to more advanced stage (>= IB) and lymph node metastases (LNM) in women with endometrioid endometrial cancer (EEC). Sonographic features and accuracy of ultrasound assessment of MI were compared in cases with the presence and the absence of the MELF pattern. [Extracted from the article]

A circuit for single‐photon avalanche diode (SPAD) current read‐out, for photon timing applications, is proposed. The circuit consists of a single‐transistor transimpedance amplifier with a gigahertz bandwidth: the feedback loop fixes the SPAD anode voltage and allows obtaining a high time resolution with a very high equivalent current threshold (almost 700 µA). The transimpedance stage is followed by a lowpass filter that reduces the crosstalk of other on‐chip detectors and makes the designed structure suitable for multi‐detector systems. The presented discrete components prototype achieves a state‐of‐the‐art resolution of 34.4 ps full width at half maximum, has negligible crosstalk between the different pixels and opens the way for the development of an integrated structure with a large number of channels. [ABSTRACT FROM AUTHOR]