Development of a portable system for checking radioactive sources using long wave radio frequency identification.
A portable system for automatically checking radioactive sources stored in lead containers at low temperatures was developed in order to prevent the discharging of orphan sources and contaminated materials from a controlled area to the general public. A radio frequency identification (RFID) system using a long wave in a frequency range of 125 kHz was composed of identification tags, a reader, a notebook computer, and software. ID tags without batteries were devised by using integrated circuits with an electrically erasable programmable read-only memory of 250 bytes and antennas. This software consisted of operating and maintenance functions. The read range of the ID tags was adjusted to around 5 cm in order to avoid accidental contamination and for discriminating the multiple sources. A water layer of 6.9 cm had no influence on communication between the ID tags and the reader. The data of the ID tags stored at +4, -20, and -80 degrees C were precisely read 4 mo later. The influence of lead was completely removed by separating the ID tags more than 1.6 cm from the lead. A reader can exactly identify the data of the ID tags within 6.0 cm at a velocity less than 9.0 cm s(-1). Performance of the software was verified using mock data. Nine lists concerning registered, disposed, and missing sources, etc., were displayed on the computer monitor and printed out. An RFID system using long waves proved to be applicable for routinely checking radioactive sources.
Mori
K
K
ING Corp, Tokyo, Japan.
Deji
S
S
Ito
S
S
Saze
T
T
Nishizawa
K
K
D004603:Elements, Radioactive; D004867:Equipment Design; D007854:Lead; D011834:Radiation Monitoring / Q000295:instrumentation*; D011846:Radio Waves; D011868:Radioisotopes; D017751:Safety Management; D012984:Software; D013686:Telemetry; D013696:Temperature; D014867:Water
D004603:Elements, Radioactive; D011868:Radioisotopes; D014867:Water; D007854:Lead