A physics marriage ceremony: DESY technician Heiko Hintz turns the big wheel that make string and cold mass a union.

A familiar view

Under the watchful eyes of industry, colleagues from Fermilab and colleagues from KEK, Module 6 is entering maturity – and matrimony. After the cavities had been assembled into a string (see NewsLine 11 May 2006), they left the pure air of the cleanroom and joined the hum of DESY's TESLA Test Facility hall. Amongst many other things, couplers have to be attached, which is not a trivial thing: to avoid impurities this has to be done under a cloud of nitrogen in less than 30 minutes. The DESY team also fitted temperature sensors to the helium tanks, tuning systems to the string and completed more than 100 other workpackages before the string was ready to meet its counterpart: the cold mass, the bit where pipes and tubes full of liquid helium get the machine down to near-absolute zero.

All experts in the test hall watched as Heiko Hintz attached an oversized steering wheel to the support structure that held both string and cold mass and slowly and very carefully turned the wheel to move the two parts closer together. "We have to be exact down to a tenth of a millimetre," said DESY team leader Kay Jensch. The two parts have to be fitted together without any trace of tension between them, otherwise the module's alignment would be in danger and its performance would go down – a catastrophe not only for FLASH, in which Module 6 will be installed, but also for the ILC, which will use the same technology.

"We're learning a lot," said Norihito Ohuchi from KEK who, like two scientists from Fermilab, are at DESY to follow the whole module process from beginning to end. When the ILC becomes a reality, cavities have to be mass-produced and experts are needed in all regions to make sure that the modules are top-quality particle runways. Bernd Griep from Accel, a German company who builds superconducting magnet systems, beam guidance systems and facilities for medicinal uses, agrees: "We want to watch every single step in the process so that we know what we need if we want to go into cavity mass production one day. Of course we don't know yet who will get the contract."

After cold mass and the string have been successfully married, the whole assembly is inserted into the characteristic yellow vacuum vessel and then takes its first test in the brand-new module test hall. Module 6 is the first complete module to go under test there – NewsLine will keep you updated about the results!

A DESY technician fixes last screws on the string.

Norihito Ohuchi from KEK is at DESY to learn all about module production.

Big muscles for small particles

-- Barbara Warmbein