Initial performance and characteristics of the PBX-M 80 kV neutral probe beam

The Princeton Beta Experiment-Modified (PBX-M) neutral probe beam (NPB) was installed to perform q-profile measurements using two different methods. The NPB has met design specifications and has operated very reliably. Ion-source conditioning is accomplished at a rate suitable for the PBX-M experimental schedule. Operation of a conditioned ion source requires little operator attention. This performance has supported the diversity and complexity of the associated experiments. The mechanical, vacuum, and magnetic performance of the NPB are described, and ion-source conditioning, timing, perveance, and modulation are discussed. Species measurements and ratios are given, and recent applications are described