Varian Associates

About: Varian Associates is a based out in . It is known for research contribution in the topics: Beam (structure) & Amplifier. The organization has 2160 authors who have published 2591 publications receiving 46002 citations.

High-efficiency velocity modulation tube employing harmonic prebunching

Abstract: A velocity modulation tube is disclosed. The tube includes beam field interaction circuits arranged along the beam path in the following order: prebuncher, floating buncher resonator, and output circuit. The prebuncher, buncher and output circuits are all tuned for a fundamental mode of resonance in the vicinity of the pass band of the tube. An abnormally long drift space, i.e., greater than 90* and preferably about 120* of reduced plasma angle is provided between interaction gaps of the prebuncher and next succeeding floating buncher, whereby the second harmonic space charge component of the resultant current density modulation of the beam produces favorable bunching of the electrons at the entrance of the buncher cavity to obtain enhanced conversion efficiency for the tube.

Retarding field electron diffraction spectrometer having improved resolution

Abstract: A retarded field electron diffraction spectrometer is disclosed which includes an electron gun for directing substantially monoenergetic electrons onto the surface to be examined of a target to produce scattered electrons from such surface. A spherical retarding grid structure is concentrically disposed of the target in the space between the target electrode and a concentric spherical fluorescent screen. A retarding potential applied to the retarding grid permits only those target scattered electrons having a potential greater than the potential of the retarding electrode to reach the fluorescent screen. The retarding grid electrode has grid openings defining electron passageways having a characteristic diameter less than three times the characteristic length thereof to improve the uniformity of the retarding field. A spherical shield grid electrode is concentrically disposed of and has a radius within the range of 0.3 to 0.8 of that of the retarding grid to enhance the resolution of the spectrometer.

Gyrotron oscillators for fusion heating

Abstract: Recent experiments have been performed to determine the ultimate power capability of a 28 GHz 200 kW CW gyrotron design A power output of 342 kW CW was measured in these tests with an efficiency of 37% Progress in the development of 60 GHz 200 kW pulsed and CW gyrotrons is discussed An output of 200 kW with 100 msec pulse length has been achieved with the pulsed design