On 29 July 2011, two days after TULA’s arrival at the DESY-Bahrenfeld site, the tunnel builders opened the travel-out panel so that the cutterhead showed again after seven months of underground work.
On 27 July 2011 at around 22:00, the tunnel boring machine TULA (TUnnel for LAser) was outside the wall of its reception shaft. It then just had to slowly drill through the 1.50-metre-thick diaphragm wall of the construction pit and pass through the round “TULA window” in the adjoining wall of the injector building. With a “landing precision” of one millimetre, TULA arrived in its travel-out panel on the western wall of the injector building on the DESY-Bahrenfeld site.
The construction of the 2010-metre-long tunnel was not yet finished, however. Six reinforced concrete rings—the last of which connects the tunnel with the hall—were still missing. While TULA inched its way onto the large steel jack (the “shield cradle”) that was installed in the hall especially for this purpose, the tunnel builders assembled the last concrete rings. On Saturday, 6 August 2011, the boring of the tunnel tube for the superconducting accelerator of the European XFEL was finally completed!
(from joint news of the European XFEL GmbH and DESY)
