Response of 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si TLD pairs to the neutrons and photon mixtures

Abstract

Replacement of dopant P by Si in LiF:Mg,Cu,P has provided an improved LiF:Mg,Cu,Si TLD material. Responses of indigenously developed Korean NaturalLiF:Mg,Cu,Si. 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si TLDs to gamma rays and neutrons were evaluated and compared with the commercially available LiF based TLDs. The intrinsic gamma ray sensitivity of NaturalLiF:Mg,Cu,Si was found to be the highest among the studied TLDs. The gamma ray sensitivities of 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si were about 27 and 32 times higher than that of Harshaw LiF:Mg,Ti. The relative neutron sensitivities (ratio of TL/mGy to neutron and gamma rays) of 6LiF TLDs doped with Mg,Cu,P and Mg,Cu,Si were about the same but lower than that of Harshaw 6LiF:Mg,Ti (TLD-600) due to the difference in their LET dependences. The high intrinsic TL sensitivity of 6LiF:Mg,Cu,Si outweighs the higher relative neutron sensitivity of TLD-600. In the testing following ANSI criteria, the performance quotient of the pairs of 6LiF:Mg,Cu,Si / 7LiF:Mg,Cu,Si held in Harshaw neutron TLD badge holders for the dosimetry in the mixed field of neutron and gamma rays was found to be less than 0.1 as against the maximum permitted value of 0.4.