D. Macina

Radiation hardness of the ABCD chip for the binary readout of silicon strip detectors in the ATLAS semiconductor tracker

The radiation hardness requirements of the ABCD chip are driven by the radiation levels expected in the ATLAS SCT after 10 years of LHC operation, which are 10 Mrad of total ionising dose and 2×10 n/cm of 1 MeV eq neutron fluence for the displacement damages. The ABCD chip, comprising both analogue and digital circuitry and realised in a BiCMOS technology, is sensitive to ionisation effects as well as to displacement damages. The recent prototype of the ABCD chip, which meets all SCT requirements, has been irradiated separately with X-ray, neutrons from a nuclear reactor, and with 24 GeV protons. In the paper we present and discuss the radiation effects observed in the ABCD chip.

Performance of the electrical module prototypes for the ATLAS silicon tracker

Electrical modules for the ATLAS Silicon Tracker (SCT) have been fabricated and tested. The modules consist of 6 ABCD front-end chips connected to silicon strip detectors, with the electronics hybrid and detector geometry as specified for the barrel and forward parts of the tracker. Tests were done with the second batch of the ABCD chip (ABCD2), connected to 6cm or 12cm long strip detectors. The functionality of the modules is demonstrated. The performance of modules depends on the signal gain in ABCD2 chips and on the grounding scheme. The design of the chip has been improved according to these observations. Recent results obtained with the new release of the chip (ABCD2T/NT) mounted on modules with 12cm strip detectors show the expected noise level of less than 1500 el., intrinsic stability and channel matching performance within 5%.

The development of a rad-hard CMOS chip for the binary readout of the ATLAS semiconductor tracker

A new version of the ABC (Atlas Binary Chip) has been submitted to Honeywell. The design contains many enhancements over the original ABC: new DAC circuitry for improved radiation hardness, faster and more robust logic parts and new interface elements to the CAFE chip. Each of these design elements will be described in detail as well as the status of the ongoing test program. Additionally, plans for production testing of ABC’s will be presented.

Performance of the binary readout of silicon strip detectors using the radiation hard SCT128B chip

We present a prototype binary readout module for the ATLAS Silicon Tracker employing a newly developed readout chip, SCT128B, using the DMILL radiation hard technology [1]. The module design and the basic module components including silicon strip sensors, readout chips and a ceramic hybrid are described briefly. The module performance evaluated in the course of lab test and beam test measurements is reported.

The developement of the CAFE-P/CAFE-M bipolar chips for the ATLAS semiconductor tracker

A bipolar chip has been developed to provide the frontend functions of the binary readout architecture used for the silicon strip detectors in the ATLAS Semiconductor Tracker (SCT). This chip consists of 128 channels of low noise amplification and discrimination and provides an interface to a suitable CMOS data processing chip. The chip was successfully fabricated on the Maxim CB-2 process. Preliminary results including channel-to-channel matching, stability, noise, gain, and irradiation tolerence are presented. These results are compared to the previous CAFE-M chip and the ATLAS requirements.