I have a GMC-600 which has the mica window for alpha detection, and I learned that there is risk that these windows can rupture if you go too high. Does anyone have an idea of what is “too high”? Would a trip to the mountains (less than 7000 ft over sea level) be ok?
The pressure inside such a tube is usually a few tenths of an atmosphere, making it about equal at 30,000 feet. It's possible that it may bulge out above that, depending on how flexible the mica window is. Shipping it in an unpressurized airplane compartment may be risky. Mountaintops would be fine.