Cosmic rays are a type of natural radiation that occurs in space. Some rays travel to Earth, generating small particles upon hitting the Earth's atmosphere.
These particles, called neutrons or muons, are constantly entering the atmosphere. They are said to fall into an area the size of a human palm about once a second. But they are so small that they can pass through most objects, even our bodies. We cannot feel them as they pass.
What happens when cosmic rays hit a semiconductor -- the engine of an electronic device? It sets off a reaction that partially corrupts data stored in the semiconductor.
Since it's an electrical reaction, the device and the circuit itself are left undamaged. But the data is corrupted. And even the slightest corruption can lead to malfunctions because integrated circuits these days are very small and precisely designed.
This is how cosmic rays are believed to cause malfunctions, known as "soft errors."
Soft errors are happneing
The probability of cosmic rays colliding with a semiconductor and causing a malfunction is extremely low. Engineers have theorized about such occurrences but cannot predict when or where they will happen.
Researchers at leading electronics manufacturer Hitachi recently conducted tests to ascertain the frequency of soft errors. The experiments consisted of lining up about 1,000 semiconductors and waiting for the soft errors. They were waiting for the cosmic rays to arrive.
The researchers waited one month before checking the semiconductors' records. 11 malfunctions were detected. Extrapolated to smartphones in use around the world, the results indicate that malfunctions are being caused in 300,000 devices every day.
The researchers say they believe this was the first time soft error frequency had been confirmed.
Senior researcher at Hitachi Tadanobu Toba says, "I used to design and develop devices, so I knew about soft errors. But even I didn't know how they happened. Now that we have the results, everyone will recognize the importance of countermeasures."
Ready to tackle the issue
Smartphones freezing and rebooting is not a big problem, but there have been other more serious incidents believed to be the result of cosmic rays.
In 2008, an Australian aircraft made a sudden steep dive midflight. More than 100 people were injured. The government report that looked into the cause of the accident said investigators could not rule out the possibility that the aircraft's computer system had malfunctioned due to cosmic rays.
Aircrafts now have multiple semiconductors installed onboard to continue operation even if one were to malfunction.
With the ubiquity of computers and smartphones, a functioning society is hard to imagine without semiconductors. And the devices are crucial to technology that are being developed now, such as self-driving cars, drones, and robots. It may not be long before everything we need in our daily lives is linked through the Internet of Things.
With society so reliant on semiconductors, soft errors caused by cosmic rays at crucial moments and places could cause damage of an unprecedented scale. This March, a study group -- a joint venture between industry, government and academia -- held a symposium on soft errors in Osaka prefecture. Researchers warned that it's time to focus on how to deal with the problem.
Some measures have already been put in place to counter soft errors. For instance, countermeasures are in place to protect Japan's "K" supercomputer. And some computer engineers are creating devices that can detect and correct soft errors. But such measures are costly and cannot yet be implemented in every field.
Professor Masanori Hashimoto at Osaka University is a member of the study group. "People who pay attention to soft errors used to be limited to those at semiconductor companies and others involved in social infrastructure systems," he says. "But if we come to rely on the Internet of Things, more people will be mindful of the errors because the shift will require greater manpower and businesses handling electronic devices."
Professor Hashimoto's group is working to develop an easier way to detect soft errors. The group is conducting experiments at Osaka University. Its members are using an accelerator to artificially generate neutrons, the equivalent of cosmic rays, and make them collide against semiconductors.
The group teamed up with a semiconductor maker for the tests. The aim is to determine at what strength cosmic rays can cause soft errors, as well as which part of integrated circuits are vulnerable to errors.
The group hopes the results will lead to the development of semiconductors highly resistant to cosmic rays and be used to draft guidelines to prepare for soft errors.
The study is also drawing attention from businesses. 15 associations from various industries are joining the group. Members say they plan to discuss safety guidelines for self-driving vehicles to protect them from soft errors.
The number of companies and services that provide countermeasures against cosmic rays is believed to be rising. For developers of new technologies, such measures cannot be avoided. With our increasing reliance on electronic devices, soft errors are posing a new, undeniable risk to society.