Fluorescence efficiency of electrons in the atmosphere above oceans

为了探测超高能宇宙射线（UHECR），来自广泛的空气簇射的轨迹的大气荧光可以通过反射镜光电传感器系统来测量。在这类实验中，电子激发不同密度和温度的空气产生的光子产额是估算UHECR初级能量的最基本依据。用~（13<90>）Sr β源研究了在氮气和干燥空气中辐射的光子产额和激发态寿命与压力的关系。在1000 hPa、20℃下，0.85MeV电子激发空气中300 ~ 406 nm的光子产额为3.734±0.148光子/米。这一结果已提交给天体粒子物理出版。空气中的水蒸气对荧光效率的影响正在研究中。

In order to detect ultrahigh-energy cosmic rays (UHECR), atmospheric fluorescence light from the trajectory of the extensive air shower may be measured by mirror-photosensor systems. In this type of experiment the photon yield from electrons exciting air of various densities and temperatures is most fundamental to estimate the primary energy of UHECR. An experiment has been undertaken using a ^<90>Sr β source to study the pressure dependence of photon yields, and the life times of the excited states, for radiation in nitrogen and dry air. The photon yield between 300nm and 406nm in air excited by 0.85 MeV electrons is 3.734±0.148 photons per meter at 1000 hPa and 20℃. This result has been submitted to Astroparticle Physics for publication. Effects to the fluorescence efficiency by water vapour in air is now under investigation.