TESLA Brochure - ACFA Joint Linear Collider Physics and Detector ...

A downtown accelerator which has
operated safely since 1992
1 DESY and its accelerators:
The illustration depicts
the underground tunnels
housing the PETRA and
HERA ring accelerators.
Also shown are the sites
of the four large halls
(North,South,East,West)
containing the HERA detectors.The
PETRA ring
encompasses the DESY
site.In addition to running
under residential
and commercial areas,
HERA also tunnels its way
beneath Hamburg’s
Volkspark.
2 On location:Visitors
to DESY’s “Open Day”
inspect a section of
the HERA tunnel.
Safety and the Environment
No other research institute in the world can match DESY’s experience
when it comes to operating a particle accelerator near densely populated
areas. Several accelerators are located on DESY’s main site in the
Hamburg districts of Bahrenfeld and Groß Flottbek. Not only does HERA’s
6.3-kilometer-long, ring-shaped tunnel run beneath Hamburg’s Volkspark; it
also curves its way beneath several residential and
industrial areas. The accelerator, which has been in
24-hour operation since 1992, is absolutely safe and does
not affect the environment.
An accelerator creates neither noise nor noxious fumes. It cannot explode.
When in operation, however, it does generate radiation. For this reason, no one
is allowed in its immediate proximity during operation.As the tunnel is located
sufficiently deep below the ground, the amount of radiation reaching the surface
is negligibly small.
In the case of the TESLA accelerator it amounts to less than one hundredth of
natural background radiation. This figure is based on calculations and experience
gained by DESY scientists. It has been confirmed by two independent
studies carried out by the Öko-Institut in Darmstadt and by TÜV Nord in
Hamburg.
Could problems occur in the event of an incident? The answer to this question
is “No.” This is because an incident of any kind would instantly interrupt
the acceleration of the particles. The electrons and positrons in the tunnel at
the time would be absorbed by a massive block deep below ground. The same
thing actually happens following particle collisions when the accelerator is in
operation. As a result, even should an incident occur, radiation could not be
emitted into the environment. Moreover, unlike a nuclear power plant, the accelerator
does not contain radioactive fuel. A facility such as TESLA can therefore
be built beneath inhabited areas without creating any potential risks or
endangering the environment.
23