Packaging samples for irradiation

Overview Care must be taken while packaging groundmass and mineral separates to prevent loss of sample and cross-contamination of adjacent samples. Because the geometric position of samples and standards is critical, labelling throughout the process is important. Sample packets are created, loaded with sample, put into disks, that are assembled together to be sent to the 1MW reactor at Oregon State University.

Making aluminum packets Irradiation packets are made at the time of packaging out of aluminum foil. Packet size can be easily adjusted to different amounts of sample. The bottom is sealed and the top is left open for loading.

Loading aluminum packets Purified groundmass (shown) or mineral separates are carefully weighed and delivered into open end of packet. Excess aluminum foil is removed, packet is then sealed and labelled.

Loading aluminum disks Sealed packets are loaded into wells on 2.5 cm diameter aluminum disks. Well location (1-9) in disk is recorded. Irradiation # (UW###) and disk # (A,B,C…) is marked with a sharpie pen on the side of each disk. Large grains (>1 mm) can be loaded without packets. Neutron fluence monitor crystals (standards) are placed on top of packets in several of the wells.

Loading aluminum disks For studies that require measurements of single crystals, different irradiation disks are used. Sample # for each individual crystal must be carefully recorded on a disk map sheet. Neutron fluence monitor crystals (standards) are loaded into every other well.

Assembling aluminum disks Filled, labelled disks are stacked, secured with threaded aluminum studs and nuts. Stacked disk assembly is placed into 2.54 cm diameter aluminum Triga tube (supplied by Oregon State Univ. Radiation Center). Triga tube is sent to the 1MW reactor at Oregon State University.