In March 1992, Dr Johnson published a devastating report ( DJR 218 ) that totally destroyed the case against Megrahi and indeed Libya.
Dr Johnson did a very carefull analysis of the surface of PT/35(b) and a control sample of a Thuring board – DP/347(a) – used in the manufacture of all MST-13 timers supplied to Libya in 1985/1986.
Here are his conclusions:
1) Spectra recorded from the lower surface of sample DP 347 (a) were not significantly different from those recorded from sample PT35. The slight spectral differences observed may well have been resulted from surface contamination during previous experiments. Therefore, the surface chemistries of the two samples were diagnosed as being rather similar.
2) Hence, in the same way that Report DJR92 concluded that ‘Dìtron’ and ‘Sefalam’ showed surface chemical differences to PT35 (suggesting that the boards were different); a similar elimination/conclusion could not be made in this instance (which suggested that the boards were not significantly different). However, although the surface chemistries of the two boards were not significantly different, this is far from concluding that the actual boards were of the same manufacture.
3) Spectra recorded from the upper (track) surface of sample PD 347 (a) showed clear differences in surface chemistry to those recorded from sample PT35. The major difference was that lead [Pb+] was particularly intense on PD 347 (a).
In a previous report, Dr. D. Johnson had established that the circuit tracks of PT/35(b) were covered with pure Tin. The tracks of the Thuring boards (All MST-13 timers supplied to Libya were built on Thuring boards.) are and have always been covered with a mix of Lead and Tin. PT/35(b) appears to be a forgery, probably made with very simple and easily available means at low-cost. Who did that?