Photon detection with n-propanol and C 2 H 6 O isomers

We demonstrate that a Geiger–Müller-type bandpass photon detector, suitable for inverse photoemission experiments, can be constructed from a MgF 2 entrance window that has a high-energy transmission threshold of 10.97 eV, and ethanol, a detection gas with an ionization potential of 10.48 eV. The photon detector has a mean detection energy of ℏω d =(10.89±0.07) eV and a bandpass of Δℏω d =(0.37±0.05) eV . A photon detector can also be constructed from n- propanol/MgF 2 with a mean detection energy of ℏω d =(10.76±0.07) eV and a bandpass Δℏω d =(0.41±0.05) eV . These two new detection gas/window combinations have a higher detection energy and a narrower bandpass than the dimethylether/MgF 2 detector [Δℏω d =(0.71±0.04) eV and ℏω d =10.60 eV ]. Since all three detectors utilize a MgF 2 entrance window, the photon bandpass can be changed straightforwardly by changing the detection gas. For systems that can be easily damaged by electron beams, having the freedom to open up the detector bandpass is an advantage because it can reduce the total electron exposure time.