FINAL PROJECT: Abstract and Reader's Reponse > Experimental approach to space-charge shift in mono-energetic electron beams
J, can you address this response by acknowledging the good data over the years, even with this calibration-type of error? And, any data set changes over time can be footnoted in some way, if this analysis results in a technical change within this field?
Looking forward to seeing this. Will you use Chicago style formatting/citation or IEEE?
Looking forward to seeing this. Will you use Chicago style formatting/citation or IEEE?
May 8, 2016 |
Marybeth Shea
Marybeth Shea
Electron Beam Ion Traps (EBITS) and other monoenergetic electron beams provide a crucial tool for experimental atomic physics. These devices have been used for a variety of studies, such as in the field of spectroscopy with highly charged ions. However, a recent EBIT study found a small but noticeable time dependence on the energy of the electron beam. One potential explanation is in space-charge shift: a reduction in the nominal beam energy due to repulsion between electrons in the beam. The space-charge shift is neutralized by ions in the beam path (such as in a trap). However, over time, the ions may escape, resulting in a reduction in beam energy as fewer ions neutralize the beam. As experimental studies into the stability of ion traps are scarce, an experiment to study the escape rate and subsequent effects on beam energy is proposed. Experimental and theoretical approaches are used to provide evidence to warrant an experimental investigation. Findings in this experiment should provide new information on common experimental apparatus and crucial information on the time-dependent energy shift. This shift in energy may imply the existence of unaccounted error or suggest a potential avenue for improving the accuracy of such devices.
Reader profile:
A member of a review board. This person is considering if the evidence is valid and warrants the cost of an experiment.
Reader response:
This type of device physics is very important to us as it seems to suggest wide-spread flaws in experiments. However, many high-precision experiments have been performed in the past with excellent results. In fact the EBIT device you are focusing on has been a major experimental device for over 25 years, and older devices, such as the Electron Beam Ion Source (EBIS) have been used for even longer. We imagine that any effects that you saw must be negligibly small to be overlooked for so long.