Dernière mise à jour : vendredi 12 novembre 2010, par
The telescope used for beam tests is made of 8 planes of silicon strips providing 4 (x,y) pairs of coordinates for each beam particle. The sensors are mounted between the 4th and 5th planes. The track impact extrapolated in the sensor plane is known with an accuracy of about 1 micron. The telescope is equipped with small scintillation counters providing the trigger signal.
The data acquisition system is based on an OS9 processor. Individual pixels are addressed in consecutive clock cycles and an external 12-bit ADC unit is used to digitise the raw analogue signals. Data from two consecutive frames are kept in a circular buffer memory to allow off-line Correlated Double Sampling signal processing.
A general purpose beam telescope of new generation has been constructed and tested.
Four reference planes of the telescope are based on CMOS Monolithic Active Pixel Sensors (MAPS), thinned down to less than 100 microns. Noise optimized, high precision tracking pixel sensors have been designed and fabricated for this application using AMS 0.35 OPTO process. Single sensor consists of 512x512 pixel array with a pitch of 10 µm, providing an active area of 5x5 mm2.
Measured signal-to-noise ratio for minimum ionizing particle (MIP) is more than 25 at room temperature and extrapolated single point (2D) resolution is below 1 µm. Use of such sensors for beam telescope provide an attractive solution for high precision tracking of minimum ionizing particles even in case of their relatively low energy.