[en] Although new work has generally reinforced the previous conclusions (1985), recent sheets of commercial grade CR-39 have exhibited both good neutron sensitivity, and low backgrounds, which, unlike those of earlier batches, have not increased with time. This improvement is believed to be associated with changes in the manufacturing process. In addition, this work has confirmed that a revised and simplified processing schedule produces equivalent results to the original processing schedule, and there are indications that further changes may improve the low-energy neutron response without increasing the backgrounds. Some studies of the effect of time and environment on the neutron sensitivity and background in the plastic have been undertaken. These have shown that, although slow changes take place in the plastic with time and environment, simple precautions minimise these effects, and they are not a serious obstacle to the introduction of an operational dosimeter. The most important remaining problem is that of the acceptability of the poor angular response of a single planar detector, and the possible need for an operational dosimeter to use multiple detectors with different orientations. (author)

[en] A trial operational personal neutron dosemeter based on the electrochemical etching of CR-39 is described. Experimental studies to determine the effects of time and environment on the neutron sensitivity of the plastic detector, the fading of latent tracks, and on the background observed after processing, are summarised. It is shown that environmental effects are generally not serious and can be minimised by simple precautions. The most significant remaining problem for an operational dosemeter is that of the poor angular response of a single planar detector. In addition, further reduction in the background uncertainty is very desirable, and will be essential if the recent ICRU recommendation to increase the Quality Factor to 25 is endorsed. (author)

[en] Chalk River Nuclear Laboratories are developing a new, direct reading, neutron detector called the bubble-damage detector. This paper reports on experiments to evaluate it for neutron dosimetry. The neutron energy responses, for detectors irradiated in free air and for detectors attached to phantoms, were measured using a variety of neutron sources. The results indicate that the detectors have an acceptable dose equivalent response to neutrons with energies in the range 2 keV - 14 MeV. The bubble-damage detector has a very high neutron sensitivity (up to 1.0 ± 0.2 bubbles μSv^-1) zero background and negligible sensitivity to gamma rays. However, the detectors suffered a substantial loss in neutron sensitivity with storage time before irradiation, a large variation in sensitivity with temperature during irradiation, and poor stability of the bubbles after irradiation. If these problems can be overcome with production detectors, this type of detector will have considerable potential for applications in neutron dosimetry where rapid readout of the dose equivalent is required. (author)