BELLE/SVD2 status and performance

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Abstract

A new silicon vertex detector for the BELLE experiment was installed and its operation has started successfully at the high-luminosity asymmetric energy e+e- collider KEKB in October 2003. This vertex detector provides a larger polar angle acceptance, a more precise vertex resolution and a better radiation tolerance than the previous one. The obtained performances indicate that the SVD2 works reliably as expected. Moreover, a prospective simulation study shows that the SVD2 should work under the coming higher background conditions.

Section snippets

Introduction: Description and design

The BELLE detector [1] operating at the asymmetric energy e+e- collider KEKB [2] is a large solid angle magnetic spectrometer, with the aim of studying the CP violation in the decays of neutral B mesons. The key point of this experiment is to measure the distance between B meson decay verteces, 200 μm, with good precision. For this purpose, a silicon vertex detector (SVD1) [3] was employed and it has brought us many remarkable results [4], [5], [6]. However, SVD1 covers the polar angle range 23

Performance

During the BELLE shutdown in 2003, the SVD2 was installed in the place of the SVD1 and its operation has started in October 2003 successfully. Now about a couple of months have passed without any trouble.

Reducing the radius of the innermost layer implies that the detector will suffer from a higher radiation and particle background. The expected dose level based on the current radiation is 80kRad/year [9] that is far less than the radiation tolerance of the SVD2. As shown in Fig. 2, the

Summary

For the further precise measurement of the CP violation in the neutral B meson system, the silicon vertex detector was upgraded and its operation has started successfully in October 2003. This upgrade is designed to provide a larger polar angle acceptance, a more precise vertex resolution and a better radiation tolerance than the previous vertex detector.

The observed performances are: gain stability, the S/N ratio of each half-ladder ranges from 16 to 36, the hit efficiency is more than 96%

Acknowledgements

The authors would like to express appreciation to other members in the BELLE Collaboration for many supports and advices. The authors are also deeply indebted to all institutes and universities related to the SVD2.

References (9)

  • G. Alimonti

    Nucl. Instr. and Meth. A

    (2000)
  • T. Kawasaki

    Nucl. Instr. and Meth. A

    (2002)
  • M. Friedl

    Nucl. Instr. and Meth. A

    (2004)
  • S. Mori

    Nucl. Instr. and Meth. A

    (2002)
There are more references available in the full text version of this article.

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1

Present address: KEK.

2

Present address: IHEP Beijing.

3

Visitor from Toronto University.

4

On leave from IFJ Krakow.

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