1 Introduction

The HETE-2 mission is designed to determine many gamma-ray burst (GRB) positions at high accuracy (10$^\prime$ for WXM, 10$^{\prime\prime}$ for SXC) and broadcast them rapidly (within 10 seconds) to the follow-up observers. The HETE-2 satellite has three scientific instruments: the Wide-field X-ray Monitor (WXM), Soft X-ray Camera (SXC) and French Gamma Telescope (FREGATE). The SXC is a 1-D coded mask system using MIT-LL CCID-20's as the detecting elements, and has energy coverage of 500 eV to 14 keV with 2% resolution at 6 keV and position resolution of 10$^{\prime\prime}$ for bright bursts (1 Crab; 10 s). The WXM has larger effective area and thus is more sensitive to weaker bursts than SXC, whereas SXC has superior spatial resolution. Thus the two X-ray instruments play an complemental role each other.