Improvement of test infrastructures for precision vertexing devices =================================================================== Introduction ------------ High resolution vertex detectors are essential to fully exploit the physics potential of any future collider. At the ILC in particular the precise reconstruction of interaction and decay vertices is necessary to investigate e.g. the coupling of Higgs bosons to the different quarks. Only extremely thin pixel detectors will be precise enough and will not disturb the measurement precision of outer tracking devices. The development of pixel detectors is one of the large ongoing R&D efforts within the International Linear Collider community. Many research groups in the EU are currently investigating different technological approaches. The interest is widespread beyond the HEP community since silicon pixel detectors hold great promise also in fields such as synchrotron radiation physics, astroparticle physics and medical as well as biological applications. For the R&D of silicon pixel detectors regular measurements in test beams are mandatory: Only test beams allow a full investigation of the device precision and behaviour under the relevant conditions. Currently the access to such facilities is difficult and the infrastructure at these facilities is lacking. In Europe facilities exist at DESY and at CERN. DESY provides electron beams up to 6 GeV. CERN has beams with electrons up to 100 GeV and hadrons up to 180 GeV. No dedicated test setup for silicon pixel detectors exists at either laboratory. Groups that presently use these beams have to provide their own dedicated testing equipment. This greatly increases the effort to do these measurements and makes results difficult to compare between groups and competing technologies. The general needs at a test beam facility for silicon pixel detectors is briefly outlined here: o The pixel detectors have to be mounted in a way that allows precise positioning, alignment and transverse as well as angular mouvements relative to the beam. o The pixel detectors have to be operated under different well controlled temperatures typically ranging from room temperature to -20 degrees. o Impinging beam particles have to be precisely tracked using a beam telescope with measurement stations in front and behind the detector under study. For lower energy beams the beam telescope needs to be equipped with very thin detectors in order to avoid multiple scattering. o Pixel detector have to be read out together with a device that provides precision information on where particles from the test beam impinge on the device under test. The objective of this JRA is to provide a standardised test beam setup for silicon pixel detectors that can be easily used by any group developing these detectors. The goal would be to reduce typical testing times from several months to one or two weeks and to make the test results easily comparable between different groups and competing detector technologies. This setup should initially be constructed and installed at DESY but would be transportable and could be used at different test beams as well. The JRA consists of the following subparts: o Environmental Support: Development and construction of a mounting and cooling infrastructure that admits a wide range of different devices to be quickly installed and easily operated. o Pixel Telescope: Development and construction of an ultra high precision beam telescope that allows to fully evaluate the precision properties of new devices. One of the candidate pixel technologies for the ILC vertex detector should be used in this device. o Data Acquisition and Evaluation Software: Development of a general purpose R/O system that can be quickly adopted to individual detector properties and provides concurrent readout of the beam telescope and the detector under study. Detailed description of the JRA =============================== Environmental Support --------------------- A general purpose, mobile mounting and cooling infrastructure for silicon pixel detectors will be constructed. This will accomodate a wide range of different sensors. It will permit transverse positioning of the sensors with a precision of 1 mu and angular positioning with a precision of 0.1 mrad. Devices under test can be operated in a well controlled environment under a nitrogen athmosphere at constant temperatures ranging from room temperature to -20 Centigrade. Mobility of the facility will be ensured by modular construction so that it can be disassembled and reassembled in a different location. Of the requested 2 FTEs, 1.5 are allocated for R&D to reach the requirements with respect to precision and ease of handling. 0.5 FTEs are allocated to the final construction and testing. Similarly, 50 kEUR are requested for the R&D and 100 kEUR for the final acquisition. Pixel Telescope --------------- A beam telescope with three measurement planes will be constructed. Each plane will be equipped with monolithic active pixel detectors constructed in CMOS technology. This particular technology is chosen because it is one of the competing technologies for a vertex detector for the ILC. The members of the consortium are already actively involved in R&D with these devices. It is therefore a natural choice also for the use in the beam telescope. However, in order to use these CMOS chips in the telescope additional R&D on the devices themselves as well as on thinning and on mounting has to be performed. Of the requested funds 250 kEUR are allocated for chip submissions and 50 kEUR for R&D on thinning on mounting of chips. The remaining funds are allocated to the final acquisition of the chips and the construction of the telescope. Two of the FTEs requested will be in electronics design labs of one of the partners specifically dedicated to work on chip design. 0.5 FTEs are allocated to the overall design of the telescope and another 0.5 FTEs are needed for final construction, assembly and testing. Data Acquisition and Evaluation Software ---------------------------------------- A general purpose data acquisition system with state of the art interfaces will be designed and built. This will accomodate a wide range of different pixel sensors that will be studied at test beams. The viability of the system will be demonstrated by supporting two competing pixel sensor technologies, namely DEPFETs and CCDs. The testing and evaluation will be performed by the groups actively involved in these pixel detector technologies. Of the 3 FTEs requested, two are dedicated to the development of the DAQ system and 0.5 FTEs for each of the sensor technologies tested with the facility. Timeline -------- ... tbd ... Resources --------- (Note: 1 FTE is accounted with 75 kEUR) Support and Beam DAQ Total Cooling Telescope SW Manpower(FTE) 2 3 3 8 Cost(kEUR) 150 400 50 600 Total(kEUR) 300 625 275 1200