Delivery of iron plates for the CBM beam dump

FAIR receives a 4,000-tonne brake pad

The hadron calorimeter

Preparing to lift the iron plates: As the sun rises, so do temperatures, creating the feeling of sitting in a large frying pan.

Recutting the rusty screw threads is hard work.

The first plate is lifted…

... and loaded onto a truck.

Then they travel down the motorway to Darmstadt.

Arrival at the FAIR construction site: the truck is carrying 24 tonnes – but it looks almost empty.

The plates are lifted from the lorry using a truck-mounted crane...

... and put into storage on the southern section of the construction site.

After one week, the first 500 plates are stored in Darmstadt.

Last Monday, the first of 900 iron plates weighing a total of 4,000 tonnes started making their way from the Karlsruhe Institute of Technology (KIT) to FAIR and GSI in Darmstadt. The plates will be used in one of the large experiments being set up at the new particle accelerator facility FAIR, where they will slow down and absorb the part of the ion beam that cannot be used for the experiments. The transportation process will involve some eleven semi-trailer trucks travelling every working day for three weeks, making an expected total of 161 journeys. The iron plates will be stored on the southern section of the FAIR construction site until they can be installed in the CMB detector complex.


For 30 years, the former Forschungszentrum Karlsruhe (today KIT) analysed strange showers of cosmic rays that hit the earth. The centrepiece of the facility was a so-called hadron calorimeter, consisting of detectors located between layers of iron plates of varying thickness. Over the past few years, the Karlsruhe KASCADE facility has been dismantled and the leftover iron plates can now be used by FAIR.


In the future, they will function as “beam dumps” (devices designed to absorb energy within an energetic beam) for the CBM (compressed baryonic matter) experiment, with some plates being incorporated into the CBM detector complex. As atomic nuclei are very small in comparison to their electron shell, comparatively few ion beam nuclei end up colliding with the so-called “target” nuclei, which is the point at which they break apart and pass through the CBM detector to reveal information about their composition. A large proportion of the ions simply fly through the target at the speed of light, and are then caught and absorbed by a beam dump located behind the CBM detector.


The plates are 160 x 200 cm long; twelve, 24 or 36 cm thick; and weigh either three, six or nine tonnes. Their total weight of 4,000 tonnes is equal to more than half the iron used to build the Eiffel Tower.


More information on the CBM experiment at FAIR (English)


More information on the Karlsruhe experiment KASCADE (English)

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