The Institute for High Energy Physics (IHEP) in Protvino, Russia, is producing some of the largest and most challenging chambers for the muon spectrometer of the ATLAS detector at CERN. Monitored drift-tube (MDT) chambers come in a variety of sizes, but the 192 chambers now being produced at IHEP include 16 with a length of 6.3 m and between them incorporate 60,000 precision MDT tubes.
MDTs have been constructed in many institutes in Europe, the US, Russia and China, but this is the first time that chambers of this size have been successfully produced. Despite the huge size of the chambers, the 50 μm thick anode wires are positioned to better than 20 μm. Production in Protvino is expected to finish by mid-April.
