Assuring the Quality of Impulse Voltage Calibration Results Issued by a Calibration Laboratory
This paper describes high-voltage impulse measurements made under the controlled conditions of a calibration or national measurement laboratory to establish the best agreement that could be achieved in comparison measurements on small reference dividers. This comparison to establish mutual international traceability between NRC and National Grid has shown that the peak voltage of a smooth lightning impulse was measured by both laboratories to within 0.2% with an estimated uncertainty of ±0.2% at a level of confidence not less than 95%. The authors make recommendations on how calibrations of reference measuring systems should be performed.
The measurement of short-duration impulse voltages
A description is given of a very-small-impulse voltage divider which is insulated by compressed gas. The divider was designed for the measurement of steep-front impulse waves, and its errors have been evaluated by the step-response method, using a pressurized sphere gap. It was then used for measuring the volt-time curve of a sphere gap, and the results have been compared with those obtained by others.
Magnetic plasma confinement for laser ion source.
A laser ion source (LIS) can easily provide a high current beam. However, it has been difficult to obtain a longer beam pulse while keeping a high current. On occasion, longer beam pulses are required by certain applications. For example, more than 10 micros of beam pulse is required for injecting highly charged beams to a large sized synchrotron. To extend beam pulse width, a solenoid field was applied at the drift space of the LIS at Brookhaven National Laboratory. The solenoid field suppressed the diverging angle of the expanding plasma and the beam pulse was widened. Also, it was observed that the plasma state was conserved after passing through a few hundred gauss of the 480 mm length solenoid field.