The SIMPLE Collaboration has reported results from their superheated C2ClF5 droplet detectors, including a description of acoustic discrimination between \alpha decays and nuclear recoils. Our concern is that the events in the neutron calibration data and the events identified as neutrons in the physics data are not drawn from the same parent distribution. This fact calls into question the identification of the background events as neutrons, the use of the calibration data to define the acceptance of WIMP-induced nuclear recoils, and the observation of discrimination against \alpha's.
@article{arxiv.1111.6192,
title = {Comments on "First Results of the Phase II SIMPLE Dark Matter Search"},
author = {C. E. Dahl and J. Hall and W. H. Lippincott},
journal= {arXiv preprint arXiv:1111.6192},
year = {2012}
}