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.
Fermilab, Batavia
A linear accelerator test facility called HINS has been operating at Fermilab. The goal of this program is to test new technology for the front end of an intensity frontier linac. Some of the new technologies that will be tested include: operation of multiple cavities from a single RF source using high-power vector modulators, round beam transport using superconducting solenoidal focusing, accelerating beam with spoke cavities, and a transition to superconducting RF cavities at 10 MeV. The testing has been split into four different stages: 2.5 MeV beam out of the RFQ only, acceleration through 6 room temperature cavities with quadrupole focusing, acceleration through 18 room temperature cavities with solenoidal focusing, and acceleration through the room temperature section plus one cryomodule of superconducting spoke cavities. Each stage focuses on testing the beam quality with a particular new technology. This paper describes the instrumentation necessary to verify the specified beam quality for each stage of the program.