EXHIBIT 21.1
 
                           SUBSIDIARIES OF REGISTRANT
 
    Genus Subsidiary Corporation, a California corporation.
 
    General Ionex Corporation, a Massachusetts corporation.
 
    Ionex/HEI Corporation, a Massachusetts corporation.
 
    Genus Europa GmbH, a German company.
 
    Genus Europa Ltd., a British company.
 
    Genus Europa SARL, a French company.
 
    Genus Europa S.r.l., an Italian company.
 
    Genus KK, a Japanese company.
 
    Genus Korea, Ltd., a Korean company.