Thomson scattering measurement system and euv light generation system

An EUV light generation system comprising:

• a chamber;
• a target supply device configured to supply a target into the chamber;
• a drive laser device configured to generate plasma by irradiating the target with a drive pulse laser beam and generate EUV light from the plasma;
• a probe laser device configured to output a probe pulse laser beam;
• a slit array including a plurality of first slits, provided on an optical path of Thomson scattering light generated by irradiation of a plasma region with the probe pulse laser beam, and configured to selectively allow the Thomson scattering light to pass through the first slits to divide the Thomson scattering light into a plurality of slit light beams each having a sectional longitudinal direction along a first direction of the plasma region and generate a slit light beam group of the slit light beams arrayed in a second direction intersecting the first direction;
• a transfer optical system provided on an optical path of the slit light beam group generated by division through the slit array and configured to transfer the slit light beam group to a plurality of transfer image groups separated from each other;
• a second slit provided on an optical path of light from the transfer image groups and configured to selectively allow light from a plurality of transfer images positioned on a straight line extending in a direction corresponding to the first direction to pass through the second slit, the transfer images corresponding to slit light beams at positions different from each other in the second direction in the slit light beam group among transfer images included in the transfer image groups;
• and
• a spectrometer configured to measure the spectrum waveform of the Thomson scattering light corresponding to an ion term based on the light having passed through the second slit from the transfer images.