Thick Polypropylene Window Proportional Counters For Cosmic Soft X-Ray Observation

For rocket studies of cosmic soft X-rays, thin polypropylene window proportional counters are being developed. Nearly all wavelengths less than 100 nm are now visible, and film thicknesses as thin as 50 nm have been achieved. This method may also be used to find electrons over a few keV, which have recently been shown to exist at rocket heights. The creation of thin polypropylene films, their use in proportional counters, and related gas management systems are all covered in this article. Testing and discussion of an electrostatic shutter that can distinguish between soft X-rays and low energy electrons are included.