The first and second signals observed during ultrasonic testing of a cylindrical article with a normal probe set on the article's end surface are studied. The amplitude of the second pulse caused by a reflection from a lateral wall with transformation of elastic waves is estimated relative to the amplitude of the first (ordinary bottom-reflected) pulse. It is ascertained that, under certain conditions, the amplitude of the second pulse can be comparable to or even exceed the amplitude of the first pulse. The effect of a change in the specimen radius-to-length ratio on the amplitude of the bottom signal is estimated.The necessity of testing cylindrical articles from ends using normal probes is encountered during ultrasonic testing of appropriately shaped forged pieces, axles of rolling-stock wheel pairs, etc.[1]. In acceptance tests of axles according to the regulatory document RD 32.144-2000 [2], a method of testing their sounding is used, which consists in determining the difference (in decibels) between bottom echo signals obtained from a face of a standard specimen CO-2 (at a distance of 59 mm) and from the opposite end of an axle. This axle is considered inconsistent with the requirements of the acceptance test if this difference exceeds 46 dB.It is known that, in the far-field zone of a normal probe, the amplitude of the bottom signal falls (without allowance for a decrease due to the absorption and scattering by microinhomogeneities) as a result of a divergence of the wave front of a longitudinal wave in inverse proportion to the increasing distance to the reflecting surface; this decrease in the bottom signal occurs more slowly than a decrease with the distance of echo signals from cylindrical, spherical, flat-bottomed, and other reflectors [1,3]. However, when cylindrical articles are tested from their ends, signal reflections from lateral surfaces can be observed. This leads to the appearance of additionally detected pulses (false signals), the amplitude of which, owing to a certain focusing effect of these surfaces, can be comparable with the amplitudes of signals reflected directly from the ends (bottom signals). This may complicate the discrimination of bottom signals since their selection by the time of arrival becomes obligatory. The author of this paper has performed studies of the first two echo pulses observed during ultrasonic testing from the ends of cylindrical specimens. The corresponding results are presented below.The specimens used in this study were steel cylinders no. 1 of radius b = 35 mm and length h = 142 mm and steel cylinders no. 2 with b = 45 mm and h = 210 mm. Elastic waves were emitted and received by a èêàá -Ñ 11 normal probe at a frequency of 2.5 MHz ( è 111-2.5-K12-002). Figure 1 shows (in arbitrary units) the first and second pulses observed on the screen of the AVGUR computer apparatus upon excitation and reception of elastic waves by the probe located axisymmetrically at the end of specimen no. 1. Fig. 1, pulse 1 corresponds to a bottom signal (from the opposite end). The d...

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High intensity proton linacs and storage rings are central for the development of advanced neutron sources, extending the intensity frontier in high energy physics, as drivers for the production of pions in neutrino factories or muon colliders, and for the transmutation of radioactive waste. Such high intensity beams are not attainable using conventional linear lattices. It has been shown in the single particle limit that integrable nonlinear lattices permit much larger tune spreads than conventional linear lattices, which would mitigate many of the space charge restrictions that limit intensity. In this paper, we present numerical studies of space charge effects on a trial nonlinear lattice with intense bunches. We observe that these nonlinear lattices and their accompanying tune spreads strongly mitigate halo formation using a result from the particle-core model known to cause halo formation in linear lattices.

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