** Shares of nanotechnology tools maker Oxford Instruments OXIG.L up 8.7% at 1948 p, top gainer on London's mid-caps index .FTMC
** OXIG plans to increase current share buyback programme to 100 million pounds ($134.21 million)
** Co says second-quarter order momentum improved to levels in line with last year, after significant macroeconomic disruption in the first quarter
** Co says HY order momentum for Imaging & Analysis segment is in line with expectations
** Co expects Advanced Technologies segment to deliver strong growth and improved margins for the year
** Up to Monday's close, stock had fallen 16.84%
($1 = 0.7451 pounds)
(Reporting by Simone Lobo)
((Simone.Lobo@thomsonreuters.com, +919920570373))