ING Corp. Senjyumiyamoto-cho 14-1, Adachi-ku, Tokyo, Japan.
Health Phys. 2010 Nov;99(5):680-7. doi: 10.1097/HP.0b013e3181e28be4.
Radioactive materials (sources) are managed by bookkeeping and stocktaking. The radiation protection section staffs should check the sources manually. Annual effective dose concerning stocktaking of them are estimated at some mSv concerning fingers. A radio frequency identification (RFID) tag's absorbed dose is estimated at some dozen Gy. RFID for stocktaking automatically was devised. Radiation effects on the communication performance of RFID tags were investigated by using response times and read ranges as indices. The RFID system was composed of a computer, a detector, and transponders (tag) consisting of an integrated circuit chip and an antenna. The tag is joined to the source for identification. The tags were irradiated at doses between 5 and 5,000 Gy by an x-ray irradiator. The response times and the read ranges were tracked from 40 to 23,200 min after irradiation. Relative read ranges fluctuated between 0.9 and 1.1 in the dose region less than 2,000 Gy, but fluctuated greatly in the dose region beyond 2,000 Gy. Malfunctioning tags appeared from 3,000 Gy, and all tags malfunctioned in the dose region over 4,500 Gy. The threshold dose leading to malfunction was determined to be 2,100 Gy. Time variation of relative read ranges was classified into four patterns. The pattern shifted from pattern 1 to 4 when the dose was increased. The relative read ranges lengthened in pattern 1. The relative read rages were approximately 1.0 in pattern 2. The read ranges tentatively shortened, then recovered in pattern 3. The tags malfunctioned in pattern 4. Once the tags malfunctioned, they never recovered their performance. Radiation enhances or deteriorates communication performance depending on dosage. Tags can spontaneously recover from radiation deterioration. The time variation of the read ranges can be illustrated by enhancement, deterioration, and recovery. The mechanism of four patterns is explained based on the variation of the frequency harmonization strength and activation voltage by irradiation. The annual effective dose of radiation protection section staffs can be reduced considerably.
放射性物质（源）采用账目和盘存管理。辐射防护部门的工作人员应进行手动检查。这些源的盘存的年有效剂量估计为手指的几毫希沃特。射频识别（RFID）标签的吸收剂量估计为十几个戈瑞。为此设计了用于盘存的自动 RFID。使用响应时间和读取范围作为指标，研究了 RFID 标签的辐射对通信性能的影响。RFID 系统由计算机、探测器和由集成电路芯片和天线组成的应答器（标签）组成。标签用于对源进行识别。使用 X 射线辐照器将标签照射在 5 至 5000 戈瑞的剂量下。在辐照后 40 至 23200 分钟内，跟踪了响应时间和读取范围。在小于 2000 戈瑞的剂量区域内，相对读取范围在 0.9 到 1.1 之间波动，但在超过 2000 戈瑞的剂量区域内波动很大。从 3000 戈瑞开始出现故障标签，超过 4500 戈瑞的剂量区域内所有标签都出现故障。确定导致故障的阈值剂量为 2100 戈瑞。相对读取范围的时间变化分为四种模式。当剂量增加时，模式从 1 变为 4。模式 1 中相对读取范围延长。模式 2 中相对读取范围约为 1.0。模式 3 中读取范围暂时缩短，然后恢复。模式 4 中标签出现故障。一旦标签出现故障，它们就永远无法恢复性能。辐射增强或恶化取决于剂量的通信性能。标签可以自发地从辐射劣化中恢复。读取范围的时间变化可以通过增强、恶化和恢复来表示。根据辐照后频率协调强度和激活电压的变化，解释了四种模式的机制。辐射防护部门工作人员的年有效剂量可以大大降低。
