Nuclear Instruments and Methods in Physics Research A 518 (2004) 482–485 RAPS: an innovative active pixel for particle detection integrated in CMOS technology Daniele Passeri a,b, *, Pisana Placidi a,b , Leonardo Verducci a,b , Paolo Ciampolini a,c , Guido Matrella a,c , Alessandro Marras b , Gian Mario Bilei c a Dipartimento di Ingegneria Elettronica e dell’Informazione, via Duranti 93, Perugia 06125, Italy b Dipartimento di Ingegneria dell’Informazione, Parco Area delle Scienze 181/A, Parma 43100, Italy c I.N.F.N. - Sez. di Perugia, Via Pascoli 1, Perugia 06100, Italy Abstract In this paper we discuss some design, implementation and test issues, with respect to the development of the RAPS01 chip in the framework of the Radiation Active Pixel Sensors (RAPS) INFN project. The project aimed at verifying feasibility of smart, high-resolution pixel arrays with a fully standard, submicron CMOS technology for particle detection purposes. Layout optimization of the pixel, including sensitive element and local read and amplification circuits has been carried out. Different basic pixel schemes and read-out options have been proposed and devised. Chip fabrication has been completed and test phase is now under way: to this purpose a suitable test environment has been devised and test strategies have been planned. r 2003 Elsevier B.V. All rights reserved. PACS: 85.40.e; 29.40.Wk Keywords: Active pixel; Silicon detectors; CMOS sensors 1. Introduction Solid-state, semiconductor sensors are widely used for detection of heavy-particle radiation in High Energy Physics (HEP) experiments. Re- cently, the adoption of standard CMOS technol- ogy has been suggested as a viable option for the fabrication of particle detectors, integrating sensi- tive element and related read-out circuitry on the same substrate. The inherently lower detection efficiency of standard CMOS substrates can be compensated by the possibility of integrating on- chip circuitry, taking care of signal conditioning and elaboration. Additional benefits of such a choice include: higher spatial resolution, low power consumption and radiation hardness. A few prototypes of CMOS radiation sensors have been presented in the technical literature [1,2]. In this paper, we discuss some design, implementa- tion and test issues with respect to the develop- ment of the RAPS01 chip, in the framework of Radiation Active Pixel Sensors (RAPS) INFN project. The project aimed at verifying feasibility of smart, high-resolution pixel arrays with a fully standard, submicron CMOS technology; to achieve this goal, main tasks include: physical ARTICLE IN PRESS *Corresponding author. Tel.: +39-075-585-3743; fax: +39- 075-585-3654. E-mail address: passeri@diei.unipg.it (D. Passeri). 0168-9002/$ - see front matter r 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.nima.2003.11.063