Results 1 - 10 of 1563
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[en] Both primary and secondary alcoholic moieties are very sensitive to oxidation reactions. But sometimes it is necessary to oxidized only the primary alcoholic moiety. Such cases are usually found in Food Industries. In this situation, TEMPO (1, 1, 6, 6-Tetramethyl-1-Piperidine Oxoammonium) was used as an oxidizing agent. In this paper, Alpha starch was successfully oxidized using TEMPO as the oxidizing agent in combination with sodium hypochlorite with and without sodium bromide. The oxidation of primary alcoholic moiety only and the remaining untouched secondary alcoholic moiety were proved by infrared spectroscopy method.
[en] The invention is aimed at the increase of secondary particle yield regularity. To achieve the aim in the suggested method of gradual radiation obtaining in cyclic accelerators with a rigid focusing at the end of each acceleration cycle, after exposure time of the object irradiated using the method of resonance excitation of circulating beam ends, the amplitude of vertical betatron oscillations is increased. On reaching the set degree of discordance between emittance of secondary beam and acceptance of its transport systems its accelerating voltage is switched off. Application of the method suggested facilitates regime selection of primary beam guidance to the internal target, increases the degree of secondary particle yield regularity during exposition of experimental device, simplifies processing of counting statistics during event recording in the experiments with counting technique, prevents from premature degradation of detecting equipment and thus increases operational efficiency of cyclic accelerators with rigid focusing and the quality of physical studies conducted using them
[en] The technology of the magnetic colloid preparation is described for use in fine adjustment operations involved in output of secondary particle channels on accelerators. A modified Elmore colloid preparation method is proposed eliminating magnetic deposit peptization with hydrochloric acid that is liable to cause more free Cl- ions to be formed promoting coagulation. The most suitable colloid preparation inhibitor has been found to be dodecylamine-(1-aminododecane) CH3(CH2)10CH2xNH2. The magnetic deposit composition for the novel colloid is prepared in the same manner as that for Elmore colloid
[en] During operation, the internal walls of modern particle accelerators are subjected to synchrotron radiation irradiation and/or electron bombardment. Such phenomena do affect surface properties such as the secondary electron yield, (SEY). A low SEY is a key parameter to control and overcome any detrimental effect on the accelerator performance eventually induced by the build-up of an Electron Cloud (E C). In laboratory experiments SEY reduction (called scrubbing) has been studied as a function of dose but the actual kinetic energy dependence has never been considered as an important parameter. For this reason and given the peculiar behavior observed for low-energy electrons, we decided to study this dependence accurately. Here we report results of SEY measurements performed bombarding Cu samples obtained from the Large Hadron Collider (Lhc) with different doses of electron beam with energy in the range 10-500 eV. Our results demonstrate that the potentiality of an electron beam to reduce the SEY does not only depend on its dose, but also on its energy. Furthermore, since E C build-up was predicted and observed also the DAΦNE ring, we report some preliminary measurements on the conditioning of Al samples. An overview of future experiments which we will perform in LNF is then given.
[en] The application of image processing in secondary ion mass spectrometry is discussed. The Cameca 4f SIMS uses a single microchannel plate and a highly sensitive camera in combination with an image processor with real time capabilities (Kontron IBAS). An automation procedure with image integration, extended dynamic range image acquisition and retro depth profiling is presented and illustrated with practical applications. (author)
[en] Without major improvements of the characteristics of ALS, the domain of research available to experiments will be large enough for many years. A few particular experiments can be done with the pion-muon channels despite the competition of the meson factories. But the two main directions of research will use the electrons and photons as tools. The large magnetic spectrometers of the electron scattering area used in combination with the flexible beam handling system allow to perform experiments of elastic and inelastic scattering at large momentum transfer with a good energy resolution and quasi elastic scattering with coincidences. The two experimental areas at ALS devoted to photonuclear reactions with their annihilation photon beams and tagged photon beams will allow the study of inclusive and exclusive photonuclear reactions from the collective nuclear resonances to the (3.3) baryonic resonance
[en] Scanning devices have been developed for measuring the intensity distribution of secondary particle beams. The monitors are used for rapid beam optimization in the SIN scattered proton beam. (orig.)