The GSI Helmholtz Center for Heavy Ion Research in Darmstadt operates a large accelerator facility for ions that is unique in the world. Researchers from all over the world use the facility for experiments to gain new insights into the structure of matter and the evolution of the universe. They are also developing novel applications in medicine and technology. Currently under construction in Darmstadt is the new international accelerator center FAIR, one of the largest research projects worldwide. With FAIR, matter is to be created and researched in the laboratory in a way that otherwise only occurs in the universe.


The core of the future FAIR accelerator center is the ring accelerator SIS100, which is equipped with superconducting magnets. This will have a circumference of 1.1 kilometers, while the existing GSI facility with the heavy ion synchrotron SIS18 will serve as a pre-accelerator for the new accelerator complex. Industrial shock absorbers from ACE's Magnum family will be used in one of the planned accelerator rings of the FAIR facility, the collector ring, which will be used to store and cool the ions. They serve as end position safety devices for drive units equipped with powerful linear motors. Industrial shock absorbers with the type designations MA3325EUM-14xxx with special stop sleeve and MA3325EUM-PP with PU head are mounted on the mechanical end stop of the moving linear unit. Their main task is to effectively absorb the inertia forces in the event of possible faulty controls of the linear motor drive unit and thus protect the structure. As a rule, the linear motor drive units ensure that the drive slides are moved in two directions over the course of a specified distance. This normally takes place without contact at the end of the respective distance at the stops. For reasons of mechanical protection of the drives, the engineers in Darmstadt decided to use the adjustable ACE industrial shock absorbers with thread sizes M33. These were designed in such a way that they can safely intercept the moving carriage in case it should move outside the specified range due to a malfunction of the motor's relay units.

Well equipped for the worst case scenario

The hydraulic machine elements from ACE, which can be precisely adjusted at both the front and rear, are capable of absorbing 170 Newton meters of energy per cycle with a stroke of 23.2 millimeters and can safely absorb effective mass forces of between 9 kilograms and 1.700 kilograms to a standstill safely, without rebound and without damage. If the components are used exclusively in an emergency, because deceleration is otherwise also taken over by the linear drive, additional energy overrides are permissible.

ACE's Magnum family, considered the reference class in medium-size industrial shock absorbers, is equipped with high-quality sealing technology proven in many thousands of applications. In addition, thanks to hardened guide bearings and integrated fixed stops, they prove to be extremely robust and durable under many operating conditions in continuous operation. They are used in all areas of mechanical engineering. Typical fields of application are automation and handling, for example in machine tools and machining centers, as in the case described as a mechanical safety element integrated in linear slides or at the end of the travel of swivel units to increase cycle times. Designers also use the dampers, which are infinitely adjustable thanks to the easily accessible adjustment segments, in the end positions to protect gantries or in heavy industry to cushion masses on impact plates.

In Darmstadt, the engineers opted for special stop sleeves on the one hand and polyurethane heads on the other. While the former reinforces the already standard above-average solid construction of the ACE industrial shock absorbers, the use of the special impact heads enables a noise reduction of 3 to 7 dB. With this chosen combination, everything has been done in the FAIR plant, from a purely shock-absorbing point of view, to ensure peace and quiet even in the worst case scenario.