Intercomparisons of absorbed doses and dose distributions for X-rays with effective energies 80-1 30 keV, using mailed LiF thermohminescent dosemeters, have been carried out as a part of a co-operative programme of research in Europe on late effects of radiation. The studies have demonstrated a number of discrepancies in the absolute dosimetry. In only six out of fourteen institutes, did the absorbed dose agree t o 5% relative to the standard value; with regard t o the dose distribution, in o d y five out of thirteen institutes were mice irradiations performed in conditions of uniform irradiation. The results of the intercomparisons demonstrate the need for standardization of the X-ray dosimetry if a meaningful comparison of bioIogicaI results is to be achieved.

A mouse-sized test phantom containing TL dosemeters was exposed to X-rays having a HVL value of 1.4-2.8 mm Cu. Dependence of the response of 7LiF dosemeters on the HVL of the incident beam resulted in an increase of TL response per rad in muscle for dosemeters positioned at the central axis of the phantom compared with the response of similar dosemeters exposed free-in-air. An increase of 7.3% in TL response per rad in muscle was found over the HVL range. The spread in effective energy inside the phantom was small and the dose distribution may be estimated directly from the TL response of 7LiF dosemeters at the entrance, central and exit position in the phantom.

The lyoluminescence (LL) technique using mannose, a monosaccharide, is described. Dose-response curves for 60Co-gamma-rays (5 rad to 120 krad), fission neutrons, 5.3 MeV and 15 MeV neutrons (100 rad to 20 krad) have been measured. The close tissue-equivalence of mannose makes this material well suited for dosimetric use in low energy X-ray fields for radiotherapy and radiobiology. It also provides a cheap, simple and reproducible dosemeter in industrial applications of radiation (sprouting inhibition of onions and potatoes; control of insect infestation). After correction for the gamma contamination of the neutron beam the LL signal per rad in ICRU muscle tissue from the neutron irradiations has been derived and the relative effectiveness of the LL signal for fast neutrons in mannose has been calculated as 0.34 +/- 0.03 (fission neutrons), 0.63 +/- 0.07 (5.3 MeV neutrons) and 0.74 +/- 0.05 (15 MeV neutrons). These results are compared with data from other systems. It is concluded that mannose can be used as a transfer system in neutron dosimetry, if its variation in sensitivity with neutron energy is taken into account.