Photon detection with n-propanol and C2H6O isomers

We demonstrate that a Geiger-Muller-type bandpass photon detector, suitable for inverse photoemission experiments, can be constructed from a MgF2 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 homega(d)=(10.89+/-0.07) eV and a bandpass of Deltahomega(d)=(0.37+/-0.05) eV. A photon detector can also be constructed from n-propanol/MgF2 with a mean detection energy of homega(d)=(10.76+/-0.07) eV and a bandpass Deltahomega(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/MgF2 detector [Deltahomega(d)=(0.71+/-0.04) eV and homega(d)=10.60 eV]. Since all three detectors utilize a MgF2 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. (C) 2002 American Institute of Physics.