Spectroscopic determination of magnetic fields in high energy electron beam diodes

The RITS-6 accelerator (5-11MeV, 100-200kA) at SNL is being used to evaluate the Self-Magnetic Pinch (SMP) diode as a flash x-ray radiography source¹. This diode utilizes a small, hollowed, metal cathode and a planar high atomic number anode to produce a focused electron beam (<; 3mm) which generates high energy Bremsstrahlung x-rays. During this process, electrode plasmas form and propagate in an approximately 1cm A-K vacuum gap. These plasmas are measured spectroscopically using high resolution (<;1 Angstrom) Czerny-Turner spectrometers with ICCD and/or streak camera outputs. This paper explores using a novel plasma spectroscopy method to measure the magnetic fields (1-25 Tesla) within the SMP diode. With this technique, the magnetic field effects on line shapes and fine structure features can be measured even when the line shapes are dominated by Stark or Doppler broadening. This provides a great advantage, over other techniques such as Faraday rotation or polarization spectroscopy. Several suitable line species have been identified and experimentally measured. Recent results with inferred B-fields will be presented.