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We present the results of testing a new thermoacoustic sensor designed to detect microwave pulses having durations from 3 to 120 ns at wavelengths of 0.8 and 3 cm. Operation of the sensor is based on the effect of generation of acoustic signals during absorption of microwave pulses in a radiotransparent substrate-absorber-liquid layered structure . A thin nanometer-thick film deposited on a substrate is used as an absorber. Microwaves are converted to an acoustic pulse in the film and the adjacent liquid. The pulse is received by a wideband acoustic receiver and then recorded by a digital oscilloscope. It is shown that for a pulse duration of 120 ns, the shape of the signal recorded by the thermoacoustic sensor completely corresponds to the signal of a tube-diode detector of microwave pulses. The response of the thermoacoustic sensor to shorter pulses (3 and 5 ns long) is a pulse with a duration of 18 ns which is determined by a limited frequency band of the acoustic receiver.Hot-carrier semiconductor detectors that are cooled with liquid nitrogen [1] or uncooled [2] are currently widely used to detect the shape of the envelope of high-power nanosecond microwave pulses in the centimeter-and millimeter-wave ranges. Germanium and silicon crystals are used as recording elements in such devices. Their temporal resolution is limited mainly by the parameters of the measuring circuits and usually amounts to about 1 ns [3]. By optimizing the detector design, one can make the time resolution equal to hundreds of picoseconds [4].Operation of hot-carrier detectors can be impeded greatly in the pulse-periodic regime of a microwave source due to the heating of the crystal by the displacement current even when the pulse repetition rate (PRR) is about tens through hundreds of hertz. Some disadvantages of employing cooled detectors are related to the use of liquid nitrogen. As the wavelength decreases, technological difficulties arise, which are associated with the detector manufacturing, since the sizes of the crystal and the detector as a whole also decrease. There are detectors based on microwave tube diodes [5]. They have no PRR limitations and can have a time resolution of less than one nanosecond [6]. However, their application is limited to the centimeter-wave range. In view of these circumstances, the development of detectors capable of working in a wide frequency band and free of the above-mentioned disadvantages, including detectors based on new physical principles, seems to be of interest.In this paper, we present the results of testing an essentially new microwave sensor based on the use of the thermoacoustic effect [7]. The operation principle and the design of this sensor were described in [8]. The sensor is located in free space and is designed to record microwave pulses having durations from 1 to * vdv@cplire.ru

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The effects of pulse-repetitive X-ray radiation and microwaves on the suspension of human erythrocyte was investigated in present work taking in to account changing their electrical capacitance. It was shown that the single 5-min exposure of suspension of erythrocyte to pulse periodic x-rays and microwaves causes the changes of the capacitance. The of the effect depends on the radiation type, the pulse repetition frequency, the radiation absorbed dose (in case of x-rays) and power flow density (in the case of microwaves).

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