Novel epoxy-free construction method for fabricating dipole magnets and test results

Three model superconducting dipole magnets, lm length and having a bore diameter of 76mm, fabricated without epoxy resins or other adhesives, have been built and the first two have been tested in He I and He II. The conductor is the 23-strand Rutherford-type cable used in the Fermilab Doubler/Saver magnets, and is insulated with Mylar and Kapton. The two-layer winding is highly compessed by a system of structural support rings and tapered collets. Little training was required. Quench currents greater than 95% of short sample were obtained in He I with rise-times of 15 to 20 seconds to a central field of 4.6 T; 6.0 T in Helium II

Experiments on Forming,Compressing and Extracting Electron Rings for the Collective Acceleration of Ions

In experiments related to the development of the electron-ring accelerator, electrons were injected into a pulsed magnetic field to form rings that were then compressed radially to a small size. The injected beam had a current of about 150 A at an energy of 3.3 MeV with an energy spread of {+-} 0.1% and a pulse length duration of 20 nsec. At low intensity, an increase in the minor radius of the ring and a large loss of electrons was observed to occur during the compression cycle. At high intensity, cooperative phenomena that caused a large increase in the energy spread accompanied by particle loss were observed. Theoretical interpretation of these observations suggests that the primary source of electron loss and enlargement of the axial dimension was the crossing of single-particle resonances during compression in the presence of large magnetic field nonlinearities and perturbations. The cooperative phenomena are interpreted as resulting from a negative mass instability. Despite the large minor radius and small number of electrons, experiments on extracting the ring were performed; under acceleration the ring failed to retain its integrity because of inadequate self-focusing

Experiments on Forming Intense Rings of Electrons Suitable for the Acceleration of Ions

Electrons were injected from a 3.3-MeV 300-A accelerator into a circular orbit in a pulsed magnetic field. Trapped ring currents of 150 A (4 x 10{sup 12} electrons) were magnetically compressed from 19 cm to 3.5 cm radii and simultaneously accelerated from 3.3 MeV to 18 MeV in energy. The rms dimensions of the cross section of the ring after compression were a = 2.3 {+-} 0.2 mm radially and b = 1.6 {+-} 0.2 mm axially. The lifetime of the ring was typically 5.5 msec, and was determined by the decay of the magnetic field after compression. This lifetime could be decreased by the addition of hydrogen gas, indicating the focusing effect of the trapped positive ions