Construction of the Advanced Detectors for KEK B-factory.

国家高能物理实验室（KEK）正在建造一个不对称的B工厂。研究B介子衰变CP破坏的贝儿探测器正在建设中。预计贝儿实验将通过测量CKM三角形的三个角和三条边来提供B介子系统CP破坏的确定性测试。为了实现这一目标，一个很好的测量B衰变顶点和一个优秀的p/K识别高达4 GeV/c是必要的。在这个项目中，我们研究了B工厂的硅微顶点探测器（SVD）的优化设计，现在构建了一个由双面硅条探测器（DSSD）和双金属层（DML）制成的z带读出。我们成功地设计和测试了一个具有宽n条间距DML的大容量固态硬盘、一个具有8单元模拟存储器的128通道低噪声存储器芯片（SMAASH芯片）、一种新的探测器单元和DAQ触发模块的凸点键合组装方法。为了使SMAASH芯片抗辐射，我们测试了快速热氮化（RTN）工艺，这是一种具有低温氧化的更精细（0.6-0.8微米）工艺。我们还计划尝试一种已建立的抗辐射工艺（DMILL工艺）。至于在贝儿实验的p/K分离，我们以前进行了密集的R&D研究的快速环图像切伦科夫（RICH）计数器与CsI的光阴极。不幸的是，大CsI光电阴极的量子效率不够高。在这个项目中，我们进行了混合光电管的研发研究，并作为切伦科夫光的辐射器，我们开发了一种新的低折射率，高透明的二氧化硅气凝胶瓦。这种新的气凝胶也是高度疏水的，易于处理。我们目前正在准备一个由HPT和二氧化硅气凝胶组成的原型RICH计数器的测试。

National Laboratory for High Energy Physics, KEK,is building an asymmetric B-factory. The BELLE detector to study CP violation in B meson decays is under construction. It is expected that the BELLE experiment will provide a definitive test of CP violation in the B-meson system by measuring the three angles and the three sides of the CKM triangles. To realize this goal, a good measurement of B decay vertices and an excellent p/K identification up to 4 GeV/c are necessary. In this project, we studied the optimized design of a Silicon micro-Vertex Detector (SVD) at the B-factory and now build one made of Double-sided Silicon Strip Detectors (DSSD) with a Double-Metal Layr (DML) for the z-strip readout. We designed and tested successfully a large DSSD with DML of wide n-strip pitches, a new 128ch low-noise preamplifier chip (SMAASH chip) with 8 cell analog memory, a new bump-bonding assembly method of detector unit and DAQ-trigger modules. To make the SMAASH chip rediation-hard we test the Rapid Thermal Nitridation (RTN) process, a finer (0.6-0.8 micron) process with a low temperature oxidation. We also plan to try one of established radiation-hard processes DMILL process). As for the p/K separation at the BELLE experiment, we previously performed an intensive R&D study of the fast Ring Image Cherenkov (RICH) counter with a CsI hotocathode. It turned out unfortunately that the quantum efficiency of large CsI photocathodes was not high enough. In this project we made a R&D study of a hybrid phototube and, as a radiator of the Cherenkov light, we developed a new low-index, highly-transparent Silica Aerogel tile. This new aerogel is also higly hydrophobic and easy to handle. We currently prepare a test of a prototype RICH counter consists of the HPT ant the silica aerogel.