First operation of a 72-k element hybrid silicon micropattern pixel detector array

none57We have constructed and tested silicon pixel detector arrays of 96 × 378 (36 288) sensor elements with 75 μm × 500 μm area. The low-noise signal processing circuit associated with each element occupies an identical area on a bump-bonded readout chip. The pixel cell response for ionizing particles is binary with an adjustable threshold between 4000 e− and 15 000 e−. Single chips, the array of 6 ladders and a double array have been characterized in particle test beams and in the Omega experiment WA97 at CERN. The two arrays together, staggered by ∼ 4 mm cover hermetically a 53 mm × 55 mm area with 72 576 pixels. The proportion of properly functioning pixels was 98% in the first 36 k pixel array and 80% in the second one. The ∼ 1% “always-on” pixels could be masked electronically. After masking the rate of “spurious noise hits” was 99% was measured. Tracks were reconstructed with a precision of 22 μm. The proportion of double hits (∼ 11%) depends only slightly on threshold and detector bias voltage, and for these double hits a precision of 10 μm on the particle position was obtained.E.H.M. HEIJNE; F. ANTINORI; R. ARNOLD; D. BARBERIS; H. BEKER; W. BEUSCH; P. BURGER; M. CAMPBELL; M.G. CATANESI; E. CHESI; G. DARBO; C. DA VIA; D. DI BARI; S. DI LIBERTO; D. ELIA; C.C. ENZ; M. GLASER; J.L. GUYONNET; T. GYS; H. HELSTRUP; J. HEUSER; R. HURST; A. JACHOLKOWSKI; P. JARRON; S. KERSTEN; F. KRUMMENACHER; R. LEITNER; F. LEMEILLEUR; V. LENTI; M. LETHEREN; M. LOKAJICEK; L. LOPEZ; M. LO VETERE; G. MAGGI; P. MARTINENGO; G. MEDDELER; F. MEDDI; A. MENETREY; P. MIDDELKAMP; M. MORANDO; A. MUNNS; P. MUSICO; C. NEYER; M. PALLAVICINI; F. PELLEGRINI; F. PENGG; S. POSPISIL; E. QUERCIGH; J. RIDKY; L. ROSSI; K. SAFARIK; G. SEGATO; S. SIMONE; P. TEMPESTA; H. VERWEIJ; G.M. VIERTEL; V. VRBAE. H. M., Heijne; F., Antinori; R., Arnold; Barberis, Dario; H., Beker; W., Beusch; P., Burger; M., Campbell; M. G., Catanesi; E., Chesi; G., Darbo; C., DA VIA; D., DI BARI; S., DI LIBERTO; D., Elia; C. C., Enz; M., Glaser; J. L., Guyonnet; T., Gys; H., Helstrup; J., Heuser; R., Hurst; A., Jacholkowski; P., Jarron; S., Kersten; F., Krummenacher; R., Leitner; F., Lemeilleur; V., Lenti; M., Letheren; M., Lokajicek; L., Lopez; LO VETERE, Maurizio; G., Maggi; P., Martinengo; G., Meddeler; F., Meddi; A., Menetrey; P., Middelkamp; M., Morando; A., Munns; P., Musico; C., Neyer; Pallavicini, Marco; F., Pellegrini; F., Pengg; S., Pospisil; E., Quercigh; J., Ridky; L., Rossi; K., Safarik; G., Segato; S., Simone; P., Tempesta; H., Verweij; G. M., Viertel; V., Vrb

DEVELOPMENT OF SILICON MICROPATTERN PIXEL DETECTORS

Successive versions of high speed, active silicon pixel detectors with integrated readout electronics have been developed for particle physics experiments using monolithic and hybrid technologies. Various matrices with binary output as well as a linear detector with analog output have been made. The hybrid binary matrix with 1024 cells (dimension 75 mum x 500 mum) can capture events at approximately 5 MHz and a selected event can then be read out in < 10 mus. In different beam tests at CERN a precision of 25 mum has been achieved and the efficiency was better than 99.2%. Detector thicknesses of 300 mum and 150 mum of silicon have been used. In a test with a Cd-109 source a noise level of 170 e- r.m.s. (1.4 keV fwhm) has been measured with a threshold non-uniformity of 750 e- r.m.s. Objectives of the development work are the increase of the size of detecting area without loss of efficiency, the design of an appropriate readout architecture for collider operation, the reduction of material thickness in the detector, understanding of the threshold non-uniformity, study of the sensitivity of the pixel matrices to light and low energy electrons for scintillating fiber detector readout and last but not least, the optimization of cost and yield of the pixel detectors in production