New role for the Warm Electron Beam Ion Trap
In late October 2018, the Warm Electron Beam Ion Trap (WEBIT) was delivered to the NASA/Goddard Space Flight Center (GSFC), where it is being used as a calibration source for the Resolve quantum microcalorimeter x-ray spectrometer. Resolve will be launched on the X-ray Imaging and Spectroscopy Mission (XRISM) in around 2022, and once in orbit, will measure x-ray emission from a variety of celestial sources across the 0.3 to 12 keV x-ray band, with a near constant energy resolution of ~5 electronvolts.
X-ray emission from highly charged ions produced in WEBIT, such as He-like oxygen and He-like neon, provides a significant improvement in accuracy over characteristic lines produced by standard x-ray tubes typically used for calibration purposes. WEBIT will be used as a calibration instrument for Resolve at different stages of assembly over the coming year.
WEBIT was originally designed and built by Ross Marrs and Ed Magee in the 1990s as a test stand for electron guns for use in the LLNL electron beam ion traps EBIT-I and SuperEBIT. Over the last 8 months, Ed Magee, now the LLNL EBIT facility’s lead technician, along with PLS division postdocs Tom Lockard and Natalie Hell and technicians Angelique Mangoba, Harrison Flores-Alimboyoguen, and David Layne, refurbished and tested WEBIT.
LLNL is a co-investigator institution for the XRISM satellite and is funded by NASA/GSFC not only to provide the WEBIT for calibration, but also to support calibration measurements of the infrared blocking filter employed by Resolve and to provide laboratory astrophysics measurements using LLNL’s EBIT-I and SuperEBIT between now and 2024 (two years after launch). In addition, LLNL’s Megan Eckart is the calibration lead for the XRISM/Resolve instrument and Gregory Brown and Natalie Hell are members of the XRISM science working group and Resolve instrument team.
