Betatron

During many years in Scientific Research Institutes of Nuclear Physics and Introscopy at Tomsk Polytechnical University (TPU) researches into induction electron accelerators and their uses for non-destructive radiation quality control of materials and articles have been conducted. Control sensitivity and efficiency detection experimental researches have been conducted with the high-current stereo-betatron modifications [1], and KBC-25 M and BC-50 high-current betatrons [2,3] in range of 11 MeV and 25-50 MeV radiation energy. 

Induction electron accelerators - betatrons- are widely used as radiation sources in industrial flaw detection of materials and articles of high thickness. However, relatively low radiation intensity has become the barrier for the most wider betatron use in this area. For the efficiencyincrease of radiation control method of articles, as well as for the possibility to control materials and articles of the most thickness the significant increase of betatron radiation intensity has been required. 

At betatron flaw detection not only roentgenography rate is of great meaning, but also the quality of roentgen photographs. 

Because of the large thickness x-rayed by high-current betatron (more than 1500 ram on plastic) the picture of defect situated near the front wall of the sample is too increased what makes difficult to detect in practice real dimensions of the defect. But there is a possibility of stereosurvey due to existence of two radiation beams simultaneously generated by betatron. 

Researches on detection of sensitivity and control efficiency with high-current betatron modifications KEC-25 and EC-50 were conducted in radiation energy range of 25-45 MeV. 

Transportable high-current KEC-25M betatron on 25 MeV energy with power dose of radiation on 1 m away from the target of 30 Gr/min is the source of penetrating radiation intended for flaw detection in field conditions and radiation visualization of dynamic processes [2]. 

High-current EC-50 betatron with maximal energy of accelerated electrons equaled to 50 MeV and radiation dose power 220 Gr/min on the distance of Im from the target [3] was made for experimental physical researches and activated analysis. 

KBC-25 M betatron allows to x-ray steel layer with thickness 280-340mtn in an hour at radiation energy of 25 MeV and F=2 m with the help of PT-5, D4, MX-5 and D7 film types. 

As for BC-50 betatron it is possible to fulfill radiographic control of steel with thickness of 360 mm for the same time tmd energy at focal distance of 3.0m 450 mm steel at F=1.5m, and 480mm steel at F=3.0m with the help of PT-1 film type. 

At 45 MeV mode BC-50 betatron allows to x-ray steel barrier with 500mm thickness using PT-1 film type at F=3m in less than seven minutes. During one hour exposure and at the same focal distance betatron allows to x-ray 500mm thickness steel on PT-5 film type. And 700mm thickness steel on PT-1 film type. 

High-current betatrons experiments confirm the wide practical possibilities of use of these installations for radiative control of the articles and materials with big thickness. 

G.V.Akulov, V.I.Bogdashkin, V.A.Moskalev, V.L.Nikolaev, A.V.Tzimbalist, V.V.Shashov, V.G.Shestakov - Mobile betatron installation on energy of 25 MeV for radiative visualization of dynamic processes and flaw detection in field conditions. Atomic science and technique problems. Electrophysical equipment. -1987,v.23,p. 19-21. 

A unique high-energy radiation laboratory is functioning at the Institute, in which studies Can be performed and thick items can be controlled using powerful X-ray units and betatrons. 

A completely different emission process, which can in principle provide table-top ultrashort X-ray sources up to 100 keV has been recently discovered and studied, both from an experimental and a theoretical viewpoint [9]. It can be understood as one consider that the electrons, trapped and accelerated in a plasma wake as described earlier, can also experience, in some cases, a transverse force pulling them toward the beam axis. This force is basically due to the creation of a sort of plasma channel at low electron density, which is a consequence of the ponderomotive force that expels the electrons from the laser beam axis (the ions, due to their larger inertia, being fixed). The trapped electrons thus undergo a sort of wiggler motion, thus producing so-called betatron radiation. 

Beat wave, 169 Betatron emission, 178 Betatron radiation, 168 Bismuth (Bi), 48, 58, 59 Bond-softening, 7 Bragg crystals, 125 Bragg peak, 175 Bremsstrahlung, 139, 168, 173 Bremsstrahlung photons, 159 Brunei effect, 201 Bubble regime, 171 Bulk modifications, 82, 103... 

Historically, the progress in radiation therapy has been linked mainly to technological developments. The physical selectivity of the irradiations was significantly increased when 200-kV x-rays were progressively replaced by cobalt-60, betatrons, and linear accelerators. As a consequence, the clinical results were dramatically improved. 

Betatron A doughnut-shaped accelerator in which electrons, traveling in an orbit of constant radius, are accelerated by a changing electromagnetic field. Energies up to 340 MeV have been attained in betatrons. 

Trenbolone acetate Sum of trenbolone acetate and 17 alpha-, and 17 betatron bolone, both free and conjugated, expressed as trenbolone Cattle, pig... 

It was found that a tokamak can be started as a betatron by discharging condensers through the coils of die transformer yoke. See also Particles (Subatomic). However, considerable difficulties arise in stabilizing the plasma ring in [he magnetic field. The ratio of R m A (Fig. I) is quite crilical to stability. In early experiments, the time of confinement of the plasma was found to lie hul a fraction of a second. This led to the thinking lhat as the tokamak is scaled up in size, the time of confinement may be proportional to the square of the size of the machine. 

In the strictest sense, the term gamma ray is applicable only to photons produced as a result of transitions in atomic nuclei. However, the term is also sometimes used to denote bremsstrahlung radiation produced when the high energy electrons in the beam of an electron accelerator, such as an electrostatic generator, a betatron, a synchrotron, or a linear accelerator, strike the target of that accelerator. 

In a looser sense the term radiation also includes energy emitted in the form of particles that possess mass and may or may not be electrically charger, (i.e.. a [positive] and ft [negative] and also neutrons. Beams of such particles may be considered as rays". The charged particles may all be accelerated and the high energy imparted to beams in particle accelerators such as cyclotrons, betatrons, synchrotrons, and linear accelerators. 

Subatomic charged particles (electrons, protons, deuterons) when accelerated in acyclotron or betatron. 

In addition to the penetrating power of the x-rays there are certain other characteristic phenomena encountered in radiography with the betatron not found with low voltage x-rays, such as a) A relative freedom from scattered radiation. The secondary radiation will tend to retain direction which the primary radiation originally had. Hence, no blocking is necessary around an irregular object or be-... 

Note The section on Betatron was prepd in collaboration with Kathleen G.Sheffield, formerly of PicArsn, Dover, NJ... 

CA 49,11429(1955) (Review on theoretical principles and properties of the betatron and synchrotron) 16)USNatBurStdsHandbook No 55, "Protection A-gainst Betatron-Synchrotron Radiations up to 100 Million Electron Volts , USDept of Commerce, Washington,DC(1955),52pp 17)Collier s Encyclopedia 7(1957), 190(Under Electron and Ion Accelerators) 18)F.TimpI,Technik(BerIin) 12,513-1 541-7 612-16(1957) CA 51,16119(1957) 52, 101(1958)... 

The formation of one or more cavities(air spaces or voids) in cast-loaded solid, expl or proplnt c hges is called cavitation (See under Loading of Ammunition). A cavity in a HE chge of a shell may cause premature expln in the gun because of collapse of the chge under the force of acceleration. A cavity in a propint chge may affect its ballistic characteristics(Ref 1). Cavities in loaded ammo may be discovered by x-ray devices such as Betatron(qv)... 

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