ST. PETERSBURG -- A St. Petersburg scientist whose fledgling business developed a device capable of detecting highly sophisticated plastic explosives has found a uniquely Russian market for his product: nervous bankers.


Last week officials at Kredit Petersburg told Yury Olshansky, the director of the 2-year-old joint-stock company Ratek, that they intended to buy one of the bomb detectors in connection with the sharp rise in crime directed at banks in the Russian Federation. In 1993, police registered 27 attacks on Russian banks by the so-called mafia, as well as the murders of 11 bankers.


Olshansky, a nuclear physicist by training who spent 20 years at St. Petersburg's giant Krylov Shipbuilding Research Institute before founding his 20-man business Ratek, said Central Bank officials had also expressed keen interest along with the U.S. Federal Aviation Administration and the Israeli airline El Al.


A prototype of the patented device, an offshoot of underwater mine detection technology developed at the Krylov institute, has been monitoring hand luggage for the past year at St. Petersburg's Pulkovo Airport.


According to Philip Myers, the president of Santa Barbara, a U.S.-Russian joint venture specializing in defense conversion, "It's better than anything in the United States."


Olshansky, 47, said the only other company in the world with a similar device was U.S.-based Science Applications International Corporation, or SAIC, but claimed that "the false alarm rate of my device is lower."


SAIC "has 15,000 employees and huge financial resources," he noted. "I have to use cheaper materials, cheaper electronics. So it's necessary to use more intelligence."


Myers, who is seeking Western investment for the project, said large SAIC-made machines "with all the bells and whistles" had been installed at airports in Washington and San Francisco at a cost of about $1 million each. "They work but have a lot of false alarms. And sometimes things get through."


Olshansky said his smaller version, which uses the same "thermal neutron activation analysis" technology as the SAIC model but has "many secrets," costs about $100,000.


"Some El Al technicians tested it for two days last February and were very surprised because it can detect very skillfully produced bombs -- plastic explosives in different configurations," Olshansky said.


A group of El Al officials in St. Petersburg for talks with Olshansky earlier this month refused comment.


Myers, who noted that private capital had been nearly impossible to obtain for the project, said he was applying to the Pentagon for $1.3 million dollars in defense conversion funds in an effort to start up a commercial venture to manufacture and market the bomb detectors.


"It looks as though we have a good chance at getting the money. The Pentagon wants bright minds from those military institutes doing nice commercial projects," he said.


Olshansky, more than once a spurned suitor in the search for Western investors, was more skeptical. "I'm concentrating on the Russian market now," he said. "It's too hard to get financing from the West."