means comparison of fig2 and 4 illustrates the tuned construction of the system where the filter 32 and optionally support rim 34 will flex to intimately contact their respective support structures fig5 shows a cutaway of fig4 illustrating the teflon filter and support ring that comprise the filter collection means before the filter collection means is attached to the filter holding means note the teflon filter is attached on the interior of the support ring so that the teflon will be in intimate contact with the filter holding means after it is installed fig6 shows the filter collector 32 and the filter support ring 34 before assembly as configured per above and assembled these form one independent aspect of the invention fig7 shows filter holding support base 50 it includes an interface region 52 for inertial microbalance attachment and a cupped air vacuum communicating region 54 over which a filter support screen 56 is set fig8 shows a close up of fig7 note the filter support screen locating pins 58 that provide additional strength of the assembly more important is the domed shape of the support screen this shapes forces contact of the filter collection 32 at a stable position when the system is prepared for use the dome shape also provides strength and rigidity to the screen itself as such it is able to stabilly support the filter collector to provide an excellent reference surface alone while still being quite light in weight fig9 shows support screen 56 as an electroformed or chemically etched piece it can also be fabricated out of sintered material that provides for a similar porosity as illustrated underlying the region of the screen is a curved low mass support structure in the form of a plurality of support ribs 60 as.