CONCLUSIONS: UHDR has a lower G(H(2)O(2)) than the conventional irradiation for both high LET carbon and low LET electron and x-ray beams. Both scavengers for e aq - ${\mathrm{e}}{{\mathrm{aq}}}^ - $ , N(2)O and NaNO(3), eliminate the dose-rate dependency of G(H(2)O(2)), which suggests e aq - ${\mathrm{e}}{{\mathrm{aq}}}^ - $ is the reason for decreased G(H(2)O(2)) for UHDR. Three-spilled UHDR versus one-spilled UHDR indicates that the assumption of residual radicals reducing …