4. Discussions

At first we discuss the accuracy of the LPV method. As stated in §3, the value of α (and of k) was obtained by averaging the two values, each of which corresponds to the symmetrical irradiation position. The difference between the two values is 8% for α and 12% for k (these differences were averaged over the samples). On the other hand, as shown in Fig. 14, the error in α obtained from each of the curves is less than 4%. Thus the asymetrical properties of the sample will determine the accuracy of α and k, these properties being thought to arise from the nonuniformity of the sample itself and of the implantation.