J.S.C. McKee

Axial injection of H− ions into the University of Manitoba variable energy cyclotron

Abstract Axial injection of H − ions into the University of Manitoba spiral ridge cyclotron has resulted in the production of 5 μA of extracted proton beam at 30 MeV, with a total transmission efficiency in excess of 10%. H + beams of energy up to and including 50 MeV are now available from this system.

The acceleration of deuterons by the university of Manitoba variable energy cyclotron

Abstract Deuteron beams of energies up to 21 MeV have been successfully extracted from the University of Manitoba cyclotron, and 24 MeV will shortly become available.

Design and performance of a liquid helium scintillation polarimeter

A new and improved liquid helium polarimeter has been built and tested. A uniform pulse height response has been achieved over the entire volume of the scintillator. This response depends on the uniformity of the wavelength shifter and the geometry of light collection. An experimental energy resolution of 13% for liquid helium with a 210Po alpha source has been achieved. Details of construction and operation are described.

A microcomputer-controlled, magnetic field measurement and analysis system

Abstract Current accelerator projects will involve the construction and field measurement of up to 10 000 magnets. A statistical has shown that in order to optimize the performance of an accelerator it will be necessary to measure the parameters of field strength, field uniformity and harmonic content of every magnet. If the measurements are performed at the construction site, the magnets which do not meet the required specifications can be repaired immediately. This paper describes a self-contained field measurement and analysis system, based on an IBM microcomputer, which performs all the remote control, data acquisition and data analysis functions automically. The system is of low cost such that each manufacturer can provide field parameters for each magnet as it is completed thus avoiding a logistical problem at the accelerator site.

Survey measurements of the magnetic field of the University of Manitoba spiral ridge cyclotron

Abstract A magnetic field mapping system having 52 flipping coils has been developed at the University of Manitoba. Measurements were made in vacuo with an estimated relative error of ±0.04%.

The preparation and use of liquid argon as a scintillating target for fast neutrons

Abstract An existing liquid helium neutron polarimeter has been used as a scintillating liquid argon target. The scintillations induced in liquid argon by fast neutrons are of lower intensity than those induced in liquid helium but are adequate to permit the use of an “associated particle” system for reducing background and with a moderate amount of shielding a clean scattering experiment can be performed. It is found that small impurities in the liquid argon result in strong absorption of the primary ultraviolet scintillation light. Data obtained using 36 MeV neutrons are presented.

A K X-ray fluorescent multi-strip probe for accelerator beam studies

Abstract A foil composed of a number of horizontal strips of different elemental composition is used to deduce the intensity distribution and position of H − beam inside the University of Manitoba Cyclotron, through studies of induced K X-ray fluorescence.

Polarised beam from the University of Manitoba Spiral Ridge Cyclotron

Abstract Polarised beam from a Sona source has been accelerated succesfully in the University of Manitoba Spiral Ridge Cyclotron, and the polarisation of the extracted beam measured.

The Proposed University of Manitoba Polarised and Unpolarised Light Ion Facility

A variable energy cyclotron with six separated sectors is proposed for the acceleration of polarized and unpolarized light positive and negative charge state ions. The energy range within which these ions are accelerated and extracted is given. The requirements for beam current and quality are that the accelerator should deliver high level beams with good energy resolution; the specifics of these requirements are included. The depolarization of polarized beams during acceleration should be negligible for all particles. It is proposed that the beam be injected from an external ion source at a low energy of ca. 200 KeV rather than from a pre-accelerator. The acceleration of H/sup -/ and D/sup -/ particles entails losses through collisional electron detachment and electromagnetic stripping inside the cyclotron. The loss from the former is expected to be ca. 10% for D/sup -/ at 10/sup -7/ Torr while the loss from the latter is estimated at ca. 0.04% for H/sup -/. The design parameters are presented and justified in this paper.

An isoangular scintillation volume for the study of the polarization of fast neutrons

Abstract An “isoangular” scintillation volume is described for which the light collection efficiency is practically independent of the position of the light source with the isoangular volume.