Streaked optical pyrometer for proton-driven isochoric heating experiments of solid and foam targets

Abstract

We have designed, built, and calibrated an ultrafast streaked optical pyrometer (SOP) with ∼5 ps resolution for measuring the time-resolved surface blackbody temperature of an isochorically heated plasma. The pyrometer is calibrated to measure temperatures from 0.5 eV to 25 eV, with the option of adding calibrated neutral density filters to observe hotter plasmas. We demonstrated the use of this pyrometer on isochoric heating experiments using laser-accelerated proton beams as an energy source at the f/40 beamline of the Texas Petawatt Laser. We used the large focal spot size (∼80 μm radius) of the f/40 pulses to accelerate high numbers of ∼MeV protons off 5 μm thick solid gold targets. During our experimental campaign, we heated 10 µm thick aluminum foil targets to 1–10 eV over a duration of 50 ps and also observed heating to ∼2 eV in 100 µm thick 60 mg/cm3 carbon foams using the SOP to measure both the temperature and heating timescale.