Design of improved electric potential fluctuation detector for 2 MeV heavy ion beam probe on TEXT (abstract)

The present detector system used for the TEXT heavy ion beam probe (HIBP) is not sensitive to potential fluctuations of magnitude below 10−5×Vacc where Vacc is the accelerator voltage. With the upgrade of the TEXT HIBP to 2 MeV, the minimum detectable fluctuation is on the order of 10 V under optimum conditions. A new detector system has been proposed, and a proof‐of‐concept experiment has indicated that it should be sensitive to fluctuations on the order of 1 V. The new system separates the ion beam entering the energy analyzer into ten smaller beams. The fluctuations in each smaller beam are measured individually, effectively increasing the signal by a factor of 10 without increasing detector noise. A version of the new detector system is presented that is designed specifically for the high‐energy analyzer of the 2 MeV TEXT HIBP. In addition to the improved detector set, this design includes a standard detector set for side‐by‐side comparison, as well as for measuring other plasma parameters.