The Z refurbishment project (ZR) at Sandia National Laboratories

Sandia's Z accelerator completed original construction in 1985 as PBFA II. The center portion was modified in 1996, converting from a high voltage to a high current configuration to drive z-pinch loads. The environments created have enabled critical experiments that address many Stockpile Stewardship Program (SSP) and High Energy Density Physics (HEDP) program needs. Z has since grown into a multifaceted workhorse facility. At more than 1000 shots after what was to be a provisional modification to assess scaling of z-pinch current, users are asking that Z be a stable, precision platform for a large number and variety of reliable, reproducible experiments. Much of Z was not optimized for z-pinch applications nor designed for the rigors of daily use at today's 18+ MA output level. This paper provides an overview of the Z Refurbishment (ZR) project, including performance criteria, timeline, test and integration strategies, and current status of the project.

I. INTRODUCTION

The Z Accelerator at Sandia National Laboratories began service as Particle Beam Fusion Accelerator II (PBFA II), achieving first shot on December 11, 1985. PBPA II was designed as a high voltage ion beam driver (10. 30 MV in a single-gap diode) for inertial confinement fusion (ICF) research (Figure 1) [1]. The vacuum power flow and output transmission line sections were subsequently modified in 1996 to a high current drive configuration (18–20 MA into a wire array load) for what was originally intended to be a six-month set of scaling experiments studying z. pinch loads (Figure 2) [2]. Because of the resultant success, the machine was never converted back to an ion driver; and was renamed “Z” in July 1997. Figure 1. PBFA II construction completed in 1985