A 258 m deep ice core was drilled using a 20 cm diameter thermal drill near to the Law Dome summit in November 2005 (Burn-Nunes et al., 2011). The core, designated DSS0506, was subsampled in October 2006 in a cold laboratory in a storage freezer in Hobart. For each ~1 metre long section of ice, a 35 mm x 35 mm stick was collected for chemical analysis, and subsequently decontaminated by chiselling with a microtome blade in an HEPA-filtered5 laminar flow bench in a freezer. All equipment used for the decontamination was repeatedly cleaned and stored in deionised water (Millipore MQ system, 18.2 MW/cm). The decontaminated samples were collected in polystyrene "Coulter counter" accuvettes and then melted for analysis by ion chromatograph. The remaining melted sample, usually 3 to 8 mL, was then refrozen and stored. In 2014 the remaining samples were sent to the University Ca' Foscari of Venice for bromine determination. The depth range of DSS0506 samples reported here is from 19.7 m (1991 C.E.) to 72.5 m (1929 C.E.). The 10 sampling resolution increased with depth, from 5 cm near the surface to 3 cm at depth, ensuring higher than monthly resolution at approximately 25 and 15 samples per year, respectively.