抄録
Particulate contamination control is one of the most important processes to maintain the performance of an optical sensor through its assembly, test and storage phases. The quantitative evaluation of surface cleanliness level of a satellite is the most essential for the contamination control. There are two kinds of ways to measure the surface cleanliness level. One is the way to set up collector plates as close to a satellite as possible to make accumulate suspended particulates on their surfaces, the other is to make contaminated particulates adhere to tapes and count them with a microscope. Both methods are complementary and it is necessary to compare their accuracies for the same sample to evaluate the availability of each method. In this study, six kinds of adhesive tapes were selected and their particulate collection efficiencies were compared with the method with collector plates. It was found that the collection efficiency depended not only on adhesive force but other characteristics of tapes, such as its backing materials and thickness. The cleanroom-tape with moderate adhesion had ability to strip out particles larger than 10, um, but significant amount of particles smaller than l0, um were left on objective surfaces. From the observed particle size distributions at Tanegashima Space Center, it was found that the particles with their size of 10, um had the largest contribution to area coverage and particles larger than 10/um accounted for 80% of total area coverage. The axial ratio distribution of stripped particles was almost the same as that before measured stripping though apparent axial shape of large particles stripped from objective surfaces rounded slightly due to the deformation of adhesive. Although there is a problem of remains adhesive, it was found that the tape method is effective for collecting large particles. Its handiness allows us to use for the periodical check method of the contamination control as a complementary method to the collector plates.
