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{\bf The New Radiation-hard Readout for the Forward\\
     and Backward Silicon Detectors of H1}

\vspace{7mm}
{\bf I.Tsurin}\\
University of Antwerpen, on behalf of DESY

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The long-term operation of the silicon detectors in H1
led to ageing effects in the detector's front-end \cite{aging}.
The readout chip for the forward and backward silicon strip
detectors \cite{strip} therefore has been redesigned in deep
submicron process. Besides an increased lifetime of the analog
circuitry of this chip by two orders of magnitude, the new
technology provides a better signal linearity. The radiation
effects could be predicted by a thorough simulation of the chip
in the design package with a parametrized bulk leakage current.

The second part of the redesign task was an optimization of the
trigger front-end with respect to radiation induced event upsets.
The silicon pad detectors for triggering \cite{pad} are controlled
and read out by dedicated firmware running on a high-density ALTERA
chip. Since the built-in memory cells turned out to be weak against
high radiation load, the predefined trigger patterns were encoded as
binary logic rather than storing them in memory blocks. A self-latching
circuit for the signal synchronization was implemented to prevent the
trigger provoking. An online counting of hits all over the pad detector
area for every bunch crossing makes possible to control the background
rate for HERA and the H1 experiment.

\vspace{1cm}
\begin{thebibliography}{9}
\bibitem{aging} M.Hilgers, R. Horisberger, "Development
                of a radiation hard version of the Analog
		Pipeline Chip APC128" Nucl. Instr. and
		Meth. A481 (2002) 556-565.
\bibitem{strip} M. No{\v z}i{\v c}ka, "The forward and
                backward silicon trackers of H1" Nucl.
		Instr. and Meth. A 501/1 (2003) 54-59.
\bibitem{pad}   I. Tsourine, "Development of a Fast H1
                Trigger using Silicon Pad\\Detectors"
		Nucl. Instr. and Meth. A 501/1 (2003)
		219-221.
\end{thebibliography}

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