RFID tag system for sample tracking at structural biology beamlines

We have developed and operated a sample exchange system on the macromolecular crystallography beamlines at the Photon Factory for high-throughput experiments, remote operations, and automated experiments. Automated data collection experiments are carried out according to the sample data description files. To prevent human error when preparing the samples and the files, each cassette and cryo-pin is assigned an ID. We implemented a barcode reader on the sample exchanger to identify a commercially available pin with a 2-D barcode. The barcode can be read after the robot picks up the pin from a liquid nitrogen dewar. However, several pins could not be identified due to frost growth on the barcode. To achieve 100% identification, herein we report the development of a sample tracking system with an RFID tag. The small RFID tag is fixed on the base of the cryo-pin and a reader is fixed on the tip of sample rotation axis. Preliminary tests reveal a 100% success rate when the tag-reader distance is less than 0.6 mm.