Motion of a Robot Mower with Directional Control

Russian Engineering Research - The stability of robot-mower motion in a specific direction is considered. The direction is regulated by means of an angular sensor and a programmable controller...     

A wide-range reactimeter for research reactors and critical assemblies

Translated from Atomnaya Énergiya, Vol. 69, No. 3, pp. 150–153, September, 1990.     

Vacuum performance of a carbon fibre cryosorber for the LHC LSS beam screen

A new carbon fibre material was developed at the Institute of Solid State Chemistry and Mechanochemistry at the Siberian Branch of the Russian Academy of Science (SB RAS) to meet the requirements of a cryosorber for the large hadron collider (LHC) vacuum chamber. The material must have a large sorbing capacity, a certain pumping speed, a working temperature range between 5 and 20 K, a low activation temperature (below room temperature), a certain size in order to fit into the limited space available and it should be easy to mount. The vacuum parameters of the LHC vacuum chamber prototype with a carbon fibre cryosorber mounted onto the beam screen were studied in the beam screen temperature range from 14 to 25 K at the Budker Institute of Nuclear Physics SB RAS. This carbon fibre material has shown sufficient sorption capacity for hydrogen at operational temperatures of the beam screen in the LHC long straight sections. It is also very important that this material does not crumble and makes a convenient fixation onto the beam screen in comparison to the widely used granulated charcoal. The problem of fluff and ways of reducing the quantity of fluff in the beam channel were studied. The results of these studies show that the carbon fibre material is a possible cryosorber-candidate for use in the LHC and other long vacuum system at cryogenic temperatures. The experimental set-up and results of measurements of the H₂ cryosorption capacity of this carbon fibre material are presented in this paper.     

An installation for magnetron deposition of getter coatings in narrow-aperture chambers

An installation for magnetron sputtering of thin-film coatings has been designed to deposit getter films in extended vacuum structures with a complex aperture. A solenoid used in the installation (diameter, 600 mm; length, 6000 mm; and maximum field, 800 G) makes it possible to deposit materials by sputtering onto internal walls in any type of vacuum chambers employed in modern accelerators. Results of deposition of a TiZrV getter coating in narrow-aperture aluminum vacuum chambers that will be mounted in the damping sections of a PETRA III synchrotron radiation source by DESY (Hamburg, Germany) are presented. The atomic composition and the homogeneity of the film along its length have been investigated on a channel for SR-XRF analysis at the Budker Institute of Nuclear Physics.     

The bending magnets for the LHC injection transfer lines

Two injection transfer lines, each about 2.8 km long, with 51 and 107 degree horizontal deflection, are being built to transfer protons at 450 GeV from the Super Proton Synchrotron (SPS) to the Large Hadron Collider (LHC). A total of 360 dipole magnets are required; they have been produced in the framework of the contribution of the Russian Federation to the construction of the LHC. The classical dipoles, built from laminated steel cores and copper coils, have a core length of 6.3 m, 25 mm gap height and a nominal field of 1.81 T at a current of 5270 A. The magnet design was made in collaboration between CERN and BINP. An unusual design has been chosen for the coils to cope with the limited voltage from the available power supplies. All magnets in each of the two lines will be powered in series. The coil is composed of overlapping, but electrically insulated, half coils of 3 1/2 turns each. Thus, the power connections for IN and OUT are placed on opposite magnet ends. Short copper braids are used to connect all upper or lower half coils in series and the whole string can be powered without power consuming cable links running alongside the magnets. Precautions are taken to avoid transmission line effects and hazards from differences in voltage between upper and lower half coil. Advantages and drawbacks of this concept are discussed as well as results of the acceptance test including mechanical, electrical and magnetic field measurements. Fabrication and measurement of the magnets at BINP, with the half core production subcontracted to EFREMOV, have been finished in June 2001.     

Vacuum performance of a beam screen with charcoal for the LHC long straight sections

The vacuum chamber inside the cryogenic magnets in the LHC Long Straight Sections will have a beam screen at a temperature between 5 and 20 K to protect the cold bore against the synchrotron radiation, electron and ion exposure. The desorbed molecules of H₂ will leave the inner part of the beam screen through the pumping slots on the beam screen and eventually condense on the cryosorber, which is mounted on the shadowed (outer) part of the beam screen for magnets operating at 4.5 K. The design of the experimental set-up, the results of the adsorption capacity measurements for charcoal, the pumping speed and the capture factor of the beam screen with charcoal for a proposed LHC vacuum chamber configuration are described in this paper.     

Performance of the vacuum system for the PETRA III damping wiggler section

A record low horizontal emittance of 1 nm-rad was successfully obtained in PETRA III third generation synchrotron light source. A key system that allowed reaching such value includes 20 permanent magnet damping wigglers installed in two long straight sections. The wigglers radiate almost 1 MW at maximum current of hard X-ray radiation which issues a challenge for the design of SR absorbers and vacuum system components for the damping wiggler section. The paper describes in detail the design consideration, manufacturing and experimental performance of absorbers and vacuum system. The first experimental results of PETRA III damping wiggler section operation are presented.     

Molecular cryosorption properties of porous copper, anodised aluminium and charcoal at temperatures between 10 and 20 K

New types of anodised aluminium, porous copper and charcoal-based materials are being developed as cryosorbing materials and have been studied in collaboration with a number of research institutes. The major aim was to find a suitable cryosorber with a working temperature in the range between 5 and 20 K that could be used in the LHC vacuum chamber inside the superconducting magnets at a temperature of 4.5 K and higher. The design of the experimental set-up, the results of cryosorption capacity measurements for porous copper, anodised aluminium and charcoal-based materials are described in this paper.