Dust extinction versus X-ray absorption NH N(H)/y =1.9x 1021 atoms cm-2 mag-1
Dust extinction versus X-ray absorption NH Galactic ISM
·空气分子数密度2.45x1019cm3 ·空气中氧氮元素丰度~100% ·太阳中金属元素丰度~0.2% ·10cm空气中对应太阳金属丰度大气柱密度 ~2.5X1023cm-2 6/4/2022
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ninety percent of the photons in a beam of 3 keV X-rays are absorbed by traveling through just 10 cm of air! Three methods doing X-ray astronomy ·Rocket flights 。Balloons ·Satellites 6/4/2022
• ninety percent of the photons in a beam of 3 keV X-rays are absorbed by traveling through just 10 cm of air! • Three methods doing X-ray astronomy • Rocket flights • Balloons • Satellites 6/4/2022
(0.1ke0 (200ke0 1m 1mm 7000A 100A 0.05A Radio and Microwave IR UV X-Rays Gamma Rays 800 SATELLITES 400 200 ROCKETS 100 BALLOONS 50 25 AIRCRAFT 12 6 MOUNTAINTOP OBSERVATORIES 3 6/4/202 Sea Level
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X-ray detectors ·气体正比计数器 ·微通道板 。 闪烁计 ·CCD Single photon Calorimeter 6/4/2022
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