metallurgist, joined the program and pushed for the feasibility of highly enriched uranium (HEU) fissile material and collaborated under Bashiruddin Mahmood at the PAEC– a moved that irked Khan. Preliminary studies on gaseous centrifuge were already studied by PAEC in 1967 but yielded few results. Khan advanced uranium enrichment from the expertise he had from the Urenco Group in the Netherlands. Under Khan's supervision, the Kahuta Research Laboratories (KRL) was set-up and engaged in clandestine efforts to obtain the necessary materials technology and electronic components for its developing uranium enrichment capabilities. The TPG succeeded in the earlier implosion-type weapon design in 1977–78, with the first cold test conducted in 1983 by Ishfaq Ahmad. The program evolved towards the boosted fission weapon designs that were eventually used in the Chagai-I tests in 1998. Enormous production was undertaken by the Pakistan Atomic Energy Commission for feasibility of weapons grade plutonium but parallel efforts were mounted toward weapons-grade uranium after India's test, the Smiling Buddha, in 1974. In 1983, Khan was convicted in absentia by the Court of Amsterdam for stealing centrifuge blueprints, though the conviction was overturned on a legal technicality. A nuclear proliferation ring was established by Khan through Dubai to smuggle URENCO nuclear technology to KRL after founding the Zippe method for the gas centrifuge On 11 March 1983, PAEC, led by Munir Ahmad Khan, carried out its first subcritical testing of a working nuclear device. This is also called a cold test, and was codenamed Kirana-I. There were 24 more cold tests from 1983 to 1994. Coordination between each site was overseen by the Directorate of Technical Development (DTD) under Dr. Zaman Sheikh (a chemical engineer) and Hafeez Qureshi, a mechanical engineer. The DTD was established by Munir Ahmad Khan in 1974 at the Metallurgical Laboratory and was tasked with development of tampers, reflective and explosive lenses, optics, and triggering mechanisms that are crucial in atomic weapons. First implosion design was built by TPG in 1977 and the DTD eventually conducted the cold-test on 11 March 1983, codename Kirana-I. Between 1983 and 1990, PAEC carried out 24 more cold tests of various nuclear weapon designs and shifted its focused towards tactical designs in 1987 that could be delivered by all Pakistan Air Force fighter aircraft. Dr. Ishrat Hussain Usmani's contribution to the nuclear energy programme is also fundamental to the development of atomic energy for civilian purposes as he,