Comparison of activity among fluorescent lamps and light emitting diodes lamps exposed to secondary particles in accelerator rooms

Abstract

Normal-type fluorescent lamps, three-wavelength-type fluorescent lamps, and LED lamps were exposed to secondary particles during machine operation in the four different high-energy accelerator rooms at the Fermi National Accelerator Laboratory (FNAL), USA, and Dokkyo Medical University, Japan. After the exposure of the lamps, we determined the activity produced in the lamps and examined the lighting characteristics of the lamps. In order to compare activity production among the same types of the lamps, total fourteen kinds of the lamps were used for the exposure experiments. The least activity after 25 days of the exposure was exhibited by the LED lamps. In examining the lighting characteristics of the lamps, however, it was found that the LED lamps could not be used at thermal and epithermal neutron fluence exceeding 9.7 × 10 10 cm -2. It was found that normal-type fluorescent lamps are superior to the three-wavelength-type fluorescent lamps from the point of view of activity production. We concluded that normal-type fluorescent lamps are the most suitable for lighting in high-energy accelerator rooms.