Dosimetry of the neutron beams at Hammersmith and Edinburgh

In 1976 we wrote to report a revision of neutron dosimetry at Hammersmith (Parnell & Bewley, 1976). The effect of this was that the old standard dose of 1440 rad (cGy) was changed by 8% and became 1560 rad (cGy). Dosimetry at Edinburgh was based on the new Hammersmith values. Since 1976, various protocols for neutron dosimetry have been published. It is now customary in Europe to use the European Protocol (Broerse et al, 1981). In this protocol the various factors which are used in neutron dosimetry were assigned rather different values from those previously used at Hammersmith and Edinburgh. When dosimetric measurements were made using the new protocol, the values of neutron dose, DN, turned out to be greater than the value used for clinical work at Edinburgh by 3–4% and at Hammersmith by 5–6%.