Introduction
At the DESY II testbeam, where electron and positron beams from 1 to 6GeV are available, a TPC test stand (see Figure 1) has been build up inside the EUDET project. This setup is now being improved besides other support inside the AIDA project. It is operated and being used by the LCTPC collaboration.
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Figure 1: The test setup in the DESYS T24/1 test beam area
(click on picture to see larger version).
The area hosts a sophisticated infrastructure consisting of equipment that is necessary in order to operate a gaseous detector according to the scientific program of the LCTPC collaboration. The setup comprises the 1T magnet PCMAG. The PCMAG, including a cosmic trigger setup using scintillator slabs, is mounted on a movable lifting stage.
Further, the setup includes a high voltage and a gas system including a slow control setup. In addition, a photo electron calibration system for the Large Prototype TPC is available. This consists of a pattern on the cathode plate, from which electrons are liberated when being illuminated by pulses from a UV laser. For the future, the inclusion of silicon detector layers from the former Zeus vertex detector is planned to be capable of doing reference measureme
The anode side end plate of the Large Prototype has been supplied by the University of Cornell. It is designed to house seven read-out modules of a shape and size comparable to one that could be used in the ILD TPC. They are arranged in three rows in the end plate, which have a curvature that corresponds to the radius of the outermost ring of readout modules in the ILD TPC end plates. More information about the end plate can be found on the web page at Cornell.
Several measurements with various read-out modules using different kinds of gas amplification and read-out techniques have been performed and more are planned. The results will be a crucial input to the design of the final ILD TPC.
