M. S. McAshan

Low Temperature Aspects of a Cryogenic Accelerator

The object of this paper is to identify the many low temperature aspects of a cryogenic accelerator and to indicate how these are related to the operating characteristics which might ultimately be achieved.

The Stanford Superconducting Recyclotron

With four orbits of recirculation, the HEPL superconducting recyclotron is expected to provide a high duty factor (> 70%) electron beam at 300 MeV by 1982. At present the beam has been recirculated twice and extracted. To date, maximum energy has been 156 MeV with best energy resolution (FWHM) 0.018%. The dependence of beam breakup starting currents on orbit optics has been investigated. Installation of the components for the third and fourth orbits will be completed this year.

Demonstration of the superconducting electron accelerator as a high‐intensity high‐resolution device

In recent experiments with the superconducting injector system, beam intensity and beam quality objectives for the superconducting electron accelerator have been achieved and exceeded. At 8.5 MeV and 25 μA, spreads in phase and energy of 1.2° and 9.2 keV fullwidth at half‐maximum, respectively, have been measured, and at 250 μA the spreads in the phase and energy increased by only 10%.

Unique Beam Properties of the Stanford 300 MeV Superconducting Recyclotron

Slightly more than a decade ago construction began on the Stanford University superconducting accelerator. The intention was to build a machine of great versatility with unique beam properties. Today the combination of beam enittance, energy resolution, beam current, duty factor, and beam stability that is achieved in the superconducting accelerator is unmatched in the world. The linac,together with its energy multiplying recirculation system (forming the superconducting recyclotron SCR) now provides beams with energies from 20 MeV to 230 MeV, and in the near future the upper limit will exceed 300 MeV.

Performance of 6‐m 1300‐MHz superconducting niobium accelerator structures

The design, manufacture, and performance of several 6‐m‐long 1300‐MHz superconducting niobium accelerator structures, which are part of the Stanford superconducting accelerator, are briefly described. In these standing‐wave accelerator structures, we have achieved cw energy gradients as high as 3.8 MeV/m and unloaded Qs as high as 6.9×109 measured at 3.0 MeV/m and 1.9 K. In addition, electron‐beam currents up to 5000 μA have been accelerated through the structure without exciting beam‐breakup modes.

Initial Performance of the Stanford Superconducting Recyclotron

Over the past several years the Stanford superconducting linac has been evolving from an experimental accelerator towards an operational facility capable of providing a high duty cycle electron beam for users. The linac has recently been fitted with bending magnets and other transport elements to allow its beam to be accelerated several times by the same linac sections (recirculated1). At present, with one orbit of recirculation, an 84 MeV beam has been extracted. By the end of this year we expect to have a 170 MeV beam and by the end of 1978, with the completion of four orbits, the beam energy will be 280 MeV. The beam duty cycle will be between 20% and 100%, and the maximum beam current will be between 20 ¿A and 100 ¿A.

Report on the Performance of the Superconducting Injector for the Stanford Linear Accelerator

This report describes some recent experiments performed with a prototype of the injector section eventually to be used in conjunction with the superconducting linear accelerator at Stanford University.

Status of the Stanford gravitational wave experiment

Abstract The low temperature gravitational radiation antenna under development at Stanford has now been operating for about 1 year. During this time the system has been completely evaluated and 1250 hours has been spent taking data. The antenna noise temperature has been measured at 10 mK and the sensitivity in 10−1 GPU.