Two types of capsules used in neutron activation analysis (NAA) systems with the WR-1 reactor at the Whiteshell Nuclear Research Establishment. The metal one, which is 38 mm long by 14 mm in diameter with a 10 mm central bore, is called the Iron Rabblt — it is made of very pure iron, to minimize its radioactivity after irradiation. The Iron Rabbit NAA facility delivered the irradiated capsules to either the Hot Cells or to a shielded receiver in an active lab, a few hundred metres away from WR-1. There the capsule had to be opened manually and the sample transferred manually to a measurement station. Capsules were expensive and not usually re-useable.
A new facility, designated the “Super-Rabbit”, used plastic capsules made of very pure polyethylene. The gamma activity of the samples could be measured without removing the samples from the capsules. The polyethylene cover was thermally welded to the container before usage and trimmed to size. Various-sized smaller capsules, also made of polyethylene, were used to contain the samples in both types of carriers.
