Summary: Test results of VA1 fabricated by sub­micron
technology
Masashi Yokoyama
University of Tokyo, Department of Physics
Hongo 7­3­1, Bunkyo­ku, Tokyo
Abstract
We have developed VA1 VLSI chip with AMS 0.35 µm process. DC current com­
pensation circuit is integrated. Preliminary measurement results indicate DC com­
pensation circuit works well up to 300 nA. Radiation hardness of the new chip is
measured and confirmed to be better than 20 Mrad.
1 Introduction
Due to a late­stage change of plans, the current BELLE SVD (SVD 1.0) was
constructed in a very short time (roughly one year from design to commission­
ing). Although its basic performance is satisfactory, its design[1] leaves room
for improvement. The most important limitation of SVD 1.0 is its limited radi­
ation tolerance. Although the frontend IC, the VA1, remains functional to 200
kRad, it exhibits a significant increase in noise at lower levels. Moreover, the
200­kRad level a#ords almost no margin for error in accelerator and detector
operations.
Failure of the integrated AC­coupling capacitors in the DSSDs is another

Source: Aihara, Hiroaki - Department of Physics, University of Tokyo

Collections: Physics