Design of 57.5 MHz CW RFQ structure for the Rare Isotope Accelarator Facility

The Rare Isotope Accelerator (RIA) facility includes a driver LINAC for production of 400 kW CW heavy-ion beams. The initial acceleration of heavy ions delivered from an ECR ion source can be effectively performed by a 57.5 MHz 4 m long RFQ. The principal specifications of the RFQ are: (1) formation of extremely low longitudinal emittance: (2) stable operation over a wide range of voltage for acceleration of various ion species needed for RIA operation; (3) simultaneous acceleration of two-charge states of uranium ions. CW operation of an accelerating structure leads to a number of requirements for the resonators such as high shunt impedance, efficient water cooling of all parts of the resonant cavity, mechanical stability together with precise alignment, reliable rf contacts, a stable operating mode and fine tuning of the resonant frequency during operation. To satisfy these requirements a new resonant structure has been developed. This paper discusses beam dynamics and electrodynamics design of the RFQ cavity, as well as, some aspects of the mechanical design of this low-frequency CW RFQ.     

Birefringence in solutions and films of poly[4,4'-bis(4'-<Emphasis Type="Italic">N</Emphasis>-phenoxy)diphenylsulfon]imide of 1,3 bis(3',4-dicarboxyphenoxy)benzene

Birefringence in solutions and films of poly[4,4'-bis(4''-N-phenoxy)diphenylsulfon]imide of 1,3-bis(3',4-dicarboxyphenoxy)benzene macromolecules is studied. The method of birefringence in the flow of polymer solutions in DMF allows one to determine the proper specific optical anisotropy of the repeating unit of chain β_M = +15 × 10^–27 cm³ mol/g. Spontaneous birefringence in polymer films of different thickness is studied under various incidence angles of a polarized beam. The total data analysis allows one to estimate the orientation order parameter of polymer chain fragments in the vicinity of surface S ₀ =–0.01, which is typical of flexible-chain polymers.     

On a chaotic potential field in vitreous As2Se3

Some experimental results of the vitreous As₂Se₃ investigation (the photoconductivity spectrum of volume examples, the temperature dependence of the thermoelectric E.M.F., the shift of the optical edge under the temperature and pressure) may be explained by the use of fluctuations of an internal potential field. A hypothesis about the nature of chaotic potential field is proposed, which is based on a negligible magnitude of the gap deformation potential D_g = D_c ? D_v, where D_c and D_v are deformation potentials of band edges. By this hypothesis the fluctuations of the substance density in glass generate the chaotic potential field of magnitude about a half of the gap E_g, while the gap magnitude fluctuates only slightly within some per cent of E_g. It is shown that the displacement of the optical edge at As₂Se₃ amorphization may be a demonstration of the deformation nature of the chaotic potential field in this material.     

On the contribution of Yu. A. Mitropol’skii to the development of asymptotic methods in nonlinear mechanics

We present a survey of the most important scientific results of Yu. A. Mitropol’skii in the fields of nonlinear differential equations, mathematical physics,and the theory of nonlinear oscil     

Random integral manifolds of systems of differential equations with unbounded operator in a Banach space

We establish existence conditions for a random integral manifold of a certain class of differential systems with unbounded sectorial operator and random right-hand side in a Banach space. Translated from Ukrainskii Matematicheskii Zhumal, Vol. 50, No. 12, pp. 1609–1614, December, 1998.     

Increasing the destructiveness of pulsating jets by the application of hydrodynamically active substances

We give the results of experimental studies of the destruction of plaster and coal-cement blocks by pulsating jets of water and water solutions of water-soluble solid polymer compounds on a base of polyethylene oxide. It is shown that the use of water-soluble solid polymer solutions as the working fluid in the generator of the pulsating jet leads to an increase in the depth of the holes and grooves by a factor of 1.5–3.5. Three figures. One table. Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 25, 1995, pp. 126–130.     

Influence of alcohols on the crystallization of supercooled water

T. G. Shevchenko Kiev State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 3, pp. 141–143, May–June, 1990.