An Acoustic Converter Used to Measure Ionizing Radiation Energy Loss

A monitor is proposed based on ultrasonic production when ionizing radiation passes through a medium. The recording element is a 0.2 mm aluminum plate mounted in a ceramic acoustic converter AC in the form of a wedge of thickness 2 mm. The low plate thickness minimizes the beam parameter distortion, while special technology used in the AC provides high sensitivity. The device has been calibrated in the proton beam from the ITEP accelerator at 200 MeV with 2·10⁹–6·10¹⁰ particles in a pulse and a pulse length of 70 nsec.     

Power Estimation by Maximum Likelihood for a Nonstationary Multicomponent Acoustic Signal

Power estimation is considered for a random signal consisting of several components entering a combined receiver in the presence of noise. A comparison is made with energy-matched processing.     

Measuring the Ultrasonic Field Generated in Water upon the Deceleration of a Proton Beam

The scanning-detector technique was used for the first time to observe the spatial–temporal structure of an ultrasonic field generated upon the deceleration and stopping in a water medium of a proton beam from the ITEP accelerator having an energy of 200 MeV and intensity of 4 × 10¹⁰. Measurements were performed in the near-field zone at 120 points that were located in the plane running through the beam axis. The latter coincided with the axis of the acoustic antenna that appeared. Contributions from three antenna segments were discriminated: from the extended middle part, the region of the maximum energy-release density at the end of the proton range (the Bragg peak), and from the plug near entrance of the beam into the water.     

Measurements of the Parameters of the Acoustic Radiation Accompanying the Moderation of an Intense Proton Beam in Water

Using the external proton beam of the accelerator at the Institute of Theoretical and Experimental Physics (ITEP), an experiment was performed on recording the acoustic signals accompanying the moderation (up to termination) of an intense proton beam with an energy of up to 200 MeV in water. The signals are damped quasi-periodic oscillations, whose initial period reflects the features of the radiating system. Parameters of the acoustic signal are measured in a wide range of energy release (from 10¹⁶to 1.2 × 10¹⁹eV) for three values of the beam diameter.     

The estimation of the power spectrum of a signal

An algorithm is considered which enables the power spectrum to be estimated for a discrete sample of N values of the signal in a time interval of [−T/2, +T/2] using a filter which has the narrow spectral band as a rectangular time window, but with a sidelobe level of less than 4.3 dB. Examples of several “power” filters are presented. Translated from Izmeritel'naya No. 9, pp. 65–66, September, 2008.     

An algorithm for a combined acoustic signal receiver

It is proposed sorting the instantaneous values of oscillatory velocity and acoustic pressure using the criterion of the similarity with signals in a plane wave using a combined acoustic-signal receiver. Part of the received instantaneous values are rejected, the Poynting vectors are calculated and their angular selection is carried out. Modeling showed that the algorithm enables two sources, separated by 2° in all, to be resolved even if their mean levels differ by 6 dB. __________ Translated from Izmeritel’naya Tekhnika, No. 10, pp. 59–62, October, 2007.     

Temperature Dependence of the Acoustic Signal Generated in Water by a 200-MeV Proton Beam

The temperature dependence of the acoustic signal produced in water by a proton beam with an energy of 200 MeV and an intensity of 6 × 10¹⁰ protons/cycle was measured in the temperature renge of maximum water density. The measurements were performed on the ITEP accelerator. The measurement results confirm the hypothesis of a thermal mechanism of generating ultrasound by ionized-particle beams. There are indications of possible contributions by other mechanisms.