束流发射度的测量

在束流输运系统中,快速而精确地测定束流的发射度,对于提高束流传输效率、调节并保证束流达到预期的场所,是十分重要的。通常在测定束流发射度时采用移动缝隙法或电磁偏转方法。这些方法不仅需要附加一些较复杂的装置,而且测量时费时费力。特别是这些方法都必须采用缝隙装置,在测量时截留了大部分束流流强,因而必须强迫冷却,而在测量后,这些缝隙装置又带有很强的放射性。除了以上这些问题以外,由于束流在缝隙上的散射,又使测量结果的误差增大。Fermi实验室的E.R.Gray、CERN的G.Baribaud和C.Metzger曾用测量束流剖面的方法来测定束流的发射度。他们测量一段漂移空间内三点的

Determination of beam emittance using SEM multiwire devices

The three gradient method for determination of beam emittance was described. The SEM multiwire devices set behind quadrupole or a pair of quadrupole magnets have been applied to measure the beam emittance. For obtaining better results the measured data were disposed mathematically with least square method. A computer program was written to obtain and display the beam emittance, related parameters as well as the beam ellipse. The beam emittance in both horizontal and vertical plane can be determined at same time by this method. The factors affecting the precision of measured results were discussed briefly in the paper.