Quick measurement of continuous absorption spectrum in ion beam pulse radiolysis: Application of optical multi-channel detector into transient species observation

• A quick measurement system of a continuous absorption spectrum was constructed and applied in ion beam pulse radiolysis.
• Transient absorption spectra during and after pulsed ion beam irradiation could be obtained within a few minutes.
• High sensitivity of 0.001–0.003 in absorbance was attained in the range from 260 to 660 nm.
• Transient species, (SCN)2
• −(SCN)2
• −, was observed in KSCN aqueous solution.
• Transient species having different absorption bands, Br2
• −Br2
• − at 360 nm and Br3−Br3− at 260 nm, were observed simultaneously in NaBr aqueous solutions.

A quick measurement system of a continuous absorption spectrum covering a wide range from 200 to 950 nm was constructed by employing an optical multi-channel detector. Ion beam pulse radiolysis with 12.5 MeV/u He, 18.3 MeV/u C and 17.5 MeV/u Ne ions were performed with the measurement system. Transient absorption spectrum of (SCN)2
• −(SCN)2
• − was clearly observed in KSCN aqueous solutions within a few minutes in spite of their very small absorbance, demonstrating high sensitivity of 0.001–0.003 in absorbance in the range from 260 to 660 nm as well as short measurement time of a few minutes. Two different absorption peaks attributed to Br2
• −Br2
• − and Br3−Br3− were observed simultaneously in NaBr aqueous solutions, showing powerfulness of the measurement system in overviewing chemical kinetics under ion beam irradiation especially in not well investigated chemical systems.