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Spectrally selective X-ray imaging provides improved material and tissue discrimination in comparison to state-of-art dual energy technologies that are commonly used in medical, industrial, and security applications. Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) based line scanners and small size two-dimensional X-ray sensors are emerging to the market, but the need for large scale panels is axiomatic. In this study, a seamless CdTe tile was developed that enables the implementation of large-sized, energy selective X-ray detector panels. The developed tile consists of a 64 × 64 pixel array (with 150 µm pitch) with a necessary substrate, ASIC, and CdTe crystal. The performance of the constructed seamless tile was characterized by focusing on spectral resolution and stability. In addition, a simple pixel trimming method that automates the equalization of each energy selective pixel was developed and analyzed.The obtained results suggest that the proposed concept of seamless (tileable) detector structures is a feasible approach to scale up panel sizes. The seamless tile shows comparable spectral resolution and stability performance with commercial CdTe sensors. The effect of tile to tile variation, the realization of a largescale panel, as well as the charge sharing performance, were left out of the scope and are to be studied in the next phase.

A detailed study of the magnetization reversal process in [20 Å Pt/t Å Co] 3 /100 Å IrMn/20 Å Pt multilayers with 4 Å ≤ t ≤ 9 Å is presented. The hysteresis of as-deposited films with t ≥ 5 Å is found to be asymmetric. This asymmetry is explained by a lateral variation in the perpendicular exchange bias direction due to the growth of IrMn onto multi-domain Co/Pt multilayers.

This paper presents the design and measurements of a low noise multi-channel front-end electronics for recording extra-cellular neuronal signals using microelectrode arrays. The integrated circuit contains 64 readout channels and was fabricated in CMOS 0.18 microm technology. A single readout channel is built of an AC coupling circuit at the input, a low noise preamplifier, a band-pass filter and a second amplifier. In order to reduce the number of output lines, the 64 analog signals from readout channels are multiplexed to a single output by an analog multiplexer. The chip is optimized for low noise and matching performance with the possibility of cut-off frequencies tuning. The low cut-off frequency can be tuned in the 1 Hz-60 Hz range and the high cut-off frequency can be tuned in the 3.5 kHz-15 kHz range. For the nominal gain setting at 44 dB and power dissipation per single channel of 220 microW the equivalent input noise is in the range from 6 microV-11 microV rms depending on the band-pass filter settings. The chip has good uniformity concerning the spread of its electrical parameters from channel to channel. The spread of gain calculated as standard deviation to mean value is about 4.4% and the spread of the low cut-off frequency is on the same level. The chip occupies 5x2.3 mm(2) of silicon area.

This paper presents the design and measurements of low-noise multichannel front-end electronics for recording extra-cellular neuronal signals using microelectrode arrays. The integrated circuit contains 64 readout channels and is fabricated in CMOS 180 nm technology. A single readout channel is built of an AC coupling circuit at the input, a low-noise preamplifier, a band-pass filter and a second amplifier. In order to reduce the number of output lines, the 64 analog signals from readout channels are multiplexed to a single output by an analog multiplexer. The chip is optimized for low noise and good matching performance and has the possibility of passband tuning. The low cut-off frequency can be tuned in the 1 Hz -60 Hz range while the high cut-off frequency can be tuned in the 3.5 kHz -15 kHz range. For the nominal gain setting at 44 dB and power dissipation per single channel of 220 W, the equivalent input noise is in the range from 6 V -11 V rms depending on the band-pass filter settings. The chip has good uniformity concerning the spread of its electrical parameters from channel to channel. The spread of the gain calculated as standard deviation to mean value is about 4.4% and the spread of the low cut-off frequency set at 1.6 Hz is only 0.07 Hz. The chip occupies 52.3 mm 2 of silicon area. To our knowledge, our solution is the first reported multichannel recording system which allows to set in each recording channel the low cut-off frequency within a single Hz with a small spread of this parameter from channel to channel. The first recordings of action potentials from the thalamus of the rat under urethane anesthesia are presented.