LBNL, Berkeley, California
Laboratory high energy density experiments using ion beam drivers rely upon the delivery of high-current, high-brightness ion beams with high peak intensity onto planar targets. Solid-state optical scintillators are typically used to measure the ion beam spatial profile but they display dose-dependent degradation and aging effects. These effects produce uncertainties and limit the accuracy of measuring peak beam intensities delivered to the target. For beam tuning and benchmarking the incident beam intensity, we have developed a cross-calibrating diagnostic suite that both places a lower limit on intensity and extends the upper limit of measurable peak intensity dynamic range. Absolute intensity calibration is obtained with a 3 um thick tungsten foil calorimeter. We present experimental evidence for peak intensity measures in excess of 200 kW/cm2 using a 300 kV, 25 mA, 5-20 usec K+ beam driver. Radiative models and thermal diffusion effects are discussed as they affect temporal and spatial resolution of beam intensity profiles.
