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THE FLAGSHIP of Japanese science, a particle collider known as TRISTAN,
is bound for the breaker’s yard after a short career as the world’s leading
machine of its type. This week, officials of the National Laboratory for
High-Energy Physics (KEK), at Tsukuba Science City just outside Tokyo, confirmed
widespread reports that they plan to convert the collider into a synchrotron
radiation source.

TRISTAN cost 87 billion yen (Pounds sterling 350 million). When it was
completed in 1986 it was the world’s most powerful machine for colliding
electrons and positrons. But its career has always been controversial. Some
commentators have argued that TRISTAN’s design owed more to national prestige
than to good science.

One critic, Sukeyasu ‘Steve’ Yamamoto, professor of physics at Tokyo
University, said this week: ‘The machine was far too extravagant. It’s really
appalling how much money was spent on it.’ But Yamamoto added that the collider
served a useful purpose as a morale-booster to Japanese scientists and industry,
as well as generating scientific results.

KEK, an institute belonging to the Ministry of Education, is the country’s
most highly regarded laboratory, according to a survey of Japanese scientists
last week. The institute started building TRISTAN in 1981. It aimed to create
the world’s most powerful collider, as part of the worldwide effort to confirm
the existence of elemen tary particles of matter such as the so-called top
quark.

TRISTAN collides positrons and electrons with an energy of 30 gigaelectronvolts
inside a ring 3 kilometres in circumference. The collider contributed some
valuable data. For example, it established a lower limit of mass for the
elusive top quark. However, its reign as the world’s leading centre for
high-energy physics was short. Europe’s Large Electron Positron machine
overtook it in 1989.

Officials at KEK have now launched a campaign to turn the machine into
another world-beater. They want it to be the world’s most powerful source
of synchrotron radiation (radiation emitted by charged particles circling
in a magnetic field). ‘We are confident that Japan will be number one in
that field,’ said a representative from KEK.

Synchrotron radiation is interesting for its practical applications
as well as for theoretical science. Japan’s large electronics companies,
for example, are working with X-rays from synchrotons to etch microchips
with more intricate patterns than those possible with visible or ultraviolet
light.

But the government may see the conversion plan, which will cost some
10 billion yen (Pounds sterling 40 million) as a quick way to build yet
another white elephant. Work is already under way on another device designed
to be the world’s largest synchrotron, at Harima near Osaka.

Yamamoto said that converting TRISTAN ‘would certainly be a better way
of utilising the machine than to keep on running for a long period – unless
anything unexpected happens in the next few years’. But he added a warning
against shutting TRISTAN down too quickly: ‘It should run a little bit longer
to improve statistics, so we never have to go back to that energy region
²¹²µ²¹¾±²Ô.’

Japan’s high-energy physicists, meanwhile, are looking for still more
powerful particle colliders to take their experiments further. Some pin
their hopes on the US’s Superconducting Super Collider. Others, however,
want to build a gigantic linear collider at KEK. The cost is likely to exceed
100 billion yen.