120851342
A long electromagnetic wiggler for the PALADIN free-electron laser experiments
A report is presented of the design, fabrication, and testing of a 25.6-m-long wiggler for a free-electron-laser (FEL) experiment. It is a DC iron-core electromagnetic wiggler that incorporates a number of important and unique features: permanent magnets are used to suppress saturation in the iron and extend the linear operating range; steering-free excitation allows real-time adjustment of the field taper without causing beam steering; and wiggle-plane focusing is produced by curved pole tips. The magnitude of random pole-to-pole field errors is minimized by a mechanical design concept that reduces tolerance stackup in critical locations. Three five-meter sections of this wiggler design were tested individually, and when connected together the measurements show exceptionally low levels of random errors. Detailed analysis of the error distribution has shown that the errors are not truly random, and the net effect on steering is much less than would be expected from random errors of the same magnitude. Analysis is still in progress to identify the cause of this beneficial effect. >
118956013
Beam-dump/diagnostics box for a 10-kA 50-MeV, 50-ns electron beam
We have developed a dump for the ATA beam that consists of a series of carbon plates whose collective thickness totals approximately 1.5 ranges at 50 MeV. The energy dissipated in the plates is radiated to a water-cooled wall. The dump is designed to dissipate up to 175 kW of average power. A small hole along the axis of the plates forms a beamlet that passes through an energy analyzer. The analyzer consists of a 60/sup 0/ bending magnet and two high-sensitivity beam-current/position monitors. The ratio of the beamlet current to full current is used to estimate the beam emittance.
113304388
The PEP-II-Factory septum quadrupole magnets
The PEP-II B-Factory is presently engaged design and fabrication of several unique magnets referred to as septum quadrupoles. This family of magnets is required to contain a low energy beam of positrons (3.1 GeV) and a high energy electron beam (9.0 GeV) in adjacent beam pipes housed within a common magnet. One beam will be focused while the other passes through an almost field free region. To do this, an asymmetric magnet must be designed having a pure, high quality quadrupole field in the magnet aperture and an adjacent low field bypass channel. A current sheet or ``septum`` coil must be placed between these two regions to produce the desired magnetic results. Design of this high current density septum coil presents many challenges since space between the two vacuum beam pipes where the coil must reside is very limited. This paper will describe the overall design of the septum quadrupoles and the solutions employed to achieve the required magnetic performance.
114809658
Magnet coil electrical gaskets of high compliance and ampacity
Coils employed in the magnets of the PHENIX Detector, presently under construction for RHIC (Relativistic Heavy Ion Collider) at the Brookhaven National Laboratory, are massive (weight {approximately} 8000 kG each). For that reason we subdivided them into a series of manageable subcoils that we will subsequent bolt together. Electrical terminals attached to the subcoils conductors are rigidly embedded and precisely located during vacuum impregnation. However; we anticipate some misalignment and nonuniform gaping to occur between terminals at assembly. We have elected to use electrical gaskets of compliance and ampacity between the bolted terminals to enhance the current carrying capability of the electrical joints. This paper describes the material candidates selected, the tests performed, and the relative ranking of the materials tested.
123501567
Bianchi IV metric with electromagnetic field
An exact solution of the Einstein equations with an electromagnetic field source and Bianchi IV symmetry is described. This solution possesses, in the limiting case of vanishing source tensor, a previously discovered vacuum metric.
118868035
Redshifts and Killing vectors
Current approaches to physics stress the importance of conservation laws due to spacetime and internal symmetries. In special and general relativity the generators of these symmetries are known as Killing vectors. We use them for the rigorous determination of gravitational and cosmological redshifts.
122505813
Comment on Coleman's theory of gravitation
The similarity of Coleman's theory (see abstr. A66860 of 1971) to a special case of a class of theories presented by Papapetrou (1954) is discussed.