Further studies of the stability of LiF:Mg,Cu,P (GR-200) at maximum readout temperatures between 240°C and 280°C

It has recently been shown that LiF:Mg,Cu,P (GR-200) can be read out to temperatures as high as 270°C for 12 s with negligible loss in sensitivity. In the present work the long-term sensitivity of GR-200 was studied at readout temperatures between 240°C and 280°C. The idea was that the readout at temperatures above 240°C might initiate reaction processes which influence the sensitivity only after long-term storage. No difference was found in the behaviour of GR-200 chips with 80 accumulated readouts to 240°C or 270°C and after storage of up to four months. Slight losses in sensitivity of 4% for 240°C and 10% for 270°C are observed after 80 readouts during four months storage. However, at a maximum readout temperature of 280°C, a 33% loss in sensitivity after 80 cycles is observed. In conclusion it is found that GR-200 can be read out at temperatures as high as 270°C with negligible loss in sensitivity (less than 0.1% per readout following an initialisation procedure of 1 readout) and acceptable residual signal (0.6%).