Vibrating Wire for Profile Measurements of Thin Beams
in Particle Accelerators: Preliminary Tests Using
a Laser Beam
E. G. Lazareva
Alikhanyan National Scientific Laboratory, Yerevan, Armenia
Received February 7, 2018
Abstract⎯The possibility of using a vibrating wire as a target in the method of scanning transverse
profiles of the thin beams in particle accelerators has been studied. In the case where the transverse
dimensions of the beam are comparable to the amplitude of the wire oscillations, the vibrating wire
can be used for a fast measurement of the transverse beam profile without moving the sensor. The
scanning procedure is replaced by the use of the movement of the wire during its mechanical
oscillations. The method is tested on a focused beam of a semiconductor laser with a spot size at the
focus of ~0.1 mm. The reconstruction of the transverse profile is performed on the basis of the
measurements of the photons reflected from the vibrating wire by using fast photodiodes.
Keywords: vibrating wire, laser, particle accelerator
Sensors based on a vibrating wire are widely used in many areas of physics. The property of changing
the wire oscillations frequency depending on its tension underlie the principle of a number of sensors
measuring the pressure of gases, structural stresses, viscosity of gases, and precision thermometry .
To measure transverse beam profiles the wire sensors are commonly used, where the fluxes of the
secondary particles or photons produced during the scattering of a beam on a wire material are measured.
Such a measurement method requires a moving target in the form of a wire and a secondary particles (or
photons) measurement system. Besides, in the fluxes of secondary particles or photons produced during
the scattering of a beam on a wire, a large number of background signals come into the view of
measurement system, which distort the results of measurements and reduce their accuracy.
The vibrating wire sensors (VWS) developed at the Yerevan Physical Institute have an unprecedented
accuracy and a large dynamic range (almost six orders of magnitude) [2–4]. Among them, there are
multiwire sensors, which allow us to estimate the beam profile from several points without using complex
scanning mechanisms [5, 6]. For the measurement of neutron beams, a special sensor has been developed
, in which a vibrating wire is covered with a layer of gadolinium. A modification of the sensor, scanner
has also been suggested to use the vibrating wire as a target and to measure the secondary particles /
photons formed during the interaction of the beam with the wire, synchronously with the measurement of
wire frequency oscillations. A prototype was constructed and test experiments of this setup have been
carried out on photon beams .
ISSN 1068–3372, Journal of Contemporary Physics (Armenian Academy of Sciences), 2018, Vol. 53, No. 2, pp. 136–145. © Allerton Press, Inc., 2018.
Original Russian Text © E.G. Lazareva, 2018, published in Izvestiya Natsional'noi Akademii Nauk Armenii, Fizika, 2018, Vol. 53, No. 2, pp. 181–192.