Geiger counter manufacturers and retailers are offering more affordable models to cash in on continued consumer radiation fears six months into the Fukushima triple meltdown crisis.
Consumers are snapping up the devices, which range in price from ¥10,000 to ¥1 million, to check radiation in their backyards and parks where they take their children. The cheaper models are proving the most popular.
Although the cheaper devices are generally of lower quality, they can still be effective if users have a good understanding of how they work, experts said.
“Devices that detect only gamma rays are probably good enough for individuals,” said Masahiro Fukushi, a radiation professor at Tokyo Metropolitan University.
In general, cheap devices detect only gamma rays, which are released by various isotopes of iodine and cesium.
The more expensive models can detect alpha and beta rays as well, Fukushi said. Uranium and plutonium emit alpha rays. Strontium releases beta rays. All are present in nuclear fuel rods along with cesium and iodine.
The more expensive devices also have radiation sensors for use in wider areas, allowing them to take more accurate readings, Fukushi said.
Certain portable Geiger counter models are even more expensive because they use advanced computer chips and other components that give them a wider sensor range in a compact size.
Experts typically buy devices in the ¥500,000 range that can detect alpha, beta and gamma rays and display radiation levels in a few seconds, said Genichiro Wakabayashi, a professor of radiology at Kinki University. He said it takes about 10 minutes with a cheap device to get meaningful results.
One example of an adequate Geiger counter is S.T. Corp.’s Air Counter, Fukushi said.
S.T., a Tokyo-based maker of air fresheners and other chemical goods for household use, announced July 26 that it plans to sell the Air Counter for an unusually low ¥15,750 on Oct. 20. The device measures 82 by 62 by 34 mm.
It detects only gamma rays and needs to be held still for about 10 minutes. The company managed to “set the price low by mass production,” S.T. spokeswoman Ikue Takahashi said.
S.T. plans to ship 10,000 Air Counters on Oct. 20 and is hoping to sell 50,000 units this year.
Fukushi said the Air Counter has a 20 percent margin of error, which he says is pretty good for the price because even expensive Geiger counters have a 10 to 20 percent margin of error.
“It’s very important that users understand the features of the devices they use. Otherwise, they’re not useful,” he said.
Fukushi and Wakabayashi warned against buying cheap Geiger counters sold on the Internet that do not offer detailed explanations or thorough operating manuals.
World Musen Inc., which has a contact number in Hong Kong but not in Japan, sells one such device called the Audible Radiometer for ¥11,800. The model does not have a display but beeps when it detects a certain amount of radiation. It is 95 by 55 by 20 mm.
Yamani Co., an Osaka-based stuffed animal and accessory maker, imports from the U.S. and sells cards with a radiation measuring sticker.
Together with a shoulder strap, the price tag of RADSticker is ¥2,100.
The colored portion of the sticker changes when it is exposed to radiation. But the minimum level detectable by the sticker is 250 millisieverts, the present maximum acceptable dose for nuclear plant workers, thus the device may not prove useful for most people.
The RADSticker is also available as a prize in the mechanical UFO Catcher machines at game centers. The sticker alone, however, can be ordered for ¥550 from Amazon.co.jp.
Sato Shouji, a trading company based in Kawasaki, normally sells about 300 Geiger counters priced from ¥50,000 to ¥1.2 million.
It sold about 1,600 units from March to July, a spokeswoman said. The company would have sold more if it had not run out of stock, she added.
Most of the Geiger counters sold at Sato Shouji are priced between ¥50,000 and ¥60,000, she said.