Development of Impact Ionization Dust Counter for the Space

PLANET-B是ISAS的一艘宇宙飞船，将在1999年至2001年间调查火星的高层大气和周围环境。为了弄清火星尘埃环/环面的存在和特征，将在行星b上安装一个撞击电离尘埃探测器。该探测器（PLANET-B火星尘埃计数器）是由德国慕尼黑工业大学和日本德国集团共同开发的，是HITEN和BREMSAT的慕尼黑尘埃计数器的改进型。MDC重量仅为690g，孔径面积为140cm^2。可探测的质量范围将在10^<-16>g到10^<-6>g之间，速度范围将从1km/s到70km/s以上。由于行星b的逆行椭圆轨道靠近黄道面，我们的探测器可以研究来自火卫一和火卫二的前进尘埃粒子的空间分布，相对相遇速度大于或高于1km/s。PLANET-B MDC还将测量地球周围的尘埃环境以及行星际和可能的星际尘埃颗粒。1994-1996年间，我们的成员（Sasaki, Ohashi， Nogami和Ishimoto）访问德国，讨论MDC原型和飞行模型的基本设计，模型的制造，使用超高速粉尘加速器进行校准测试。与HITEN-MDC相比，新MDC有几个优点：更大的光圈、更少的太阳能照明和三个通道。

PLANET-B is an ISAS spacecraft which will investigate the upper atmosphere and the surroundings of Mars between 1999 and 2001. To clarify the presence and characteristics of the Martian dust ring/torus, an impact ionization dust detector will be on board PLANET-B.The detector (PLANET-B Mars Dust Counter), which is an improved version of the Munich Dust Counters of HITEN and BREMSAT,is developed at Technology University of Munchen under the corporation between Japanese and Germany group.MDC weighs only 690g with an aperture area 140cm^2. The detectable mass range will be between 10^<-16>g and more than 10^<-6>g and the velocity range will be from 1km/s to more than 70km/s. Since PLANET-B executes retrograde elliptic orbits close to the zodiacal plane, our detector can investigate the spatial distribution of prograde dust particles from Phobos and Deimos with relative encounter velocity as large as or higher than 1km/s. PLANET-B MDC shall also measure the dust environment around the Earth and interplanetary and possibly interstellar dust particles.Between 1994-1996, our members (Sasaki, Ohashi, Nogami, and Ishimoto) visit Germany for discussion of basic design of proto-and flight models of MDC,manufacturing of models, calibration tests using the ultra-high velocity dust accelerator. New MDC has several advantages over HITEN-MDC : larger aperture, cut of solar illumination, and three channels.