i have taken spectra of different elements and i have used the equations (wiley 1995). but experimental time does not match with this calculation. how can i fix this problem
see following links
http://www.zess.uni-siegen.de/cms/papers/Lindner2010TimeofFlightSensorCalibration.pdf
http://www.robotic.dlr.de/fileadmin/robotic/fuchs/calibTOFcamera.pdf
In ToF mass spectrometry the relation between mass (m) and time-of-flight (t) is determined by the kinetic energy that is the same for all ions
Ekin = 1/2 m* v^2 (with v=s/t)
as also the flight path s is the same this ultimately leads to : m ~ t^2.
In practice, however, your starting time is not 0, but there is a small shift t0 (can be positive or negative): m=(t-t0)^2 * k
To work out both constants k and t0 you just need two known masses and their time of flight. If this calibration does not give reasonable masses for other substances you should check what you use for calibration, metals could oxidize and you may not see the elemental ion, but oxides...
You can find some clue in
Optics and Lasers in Engineering
Volume 54, March 2014, Pages 187-196
Thank you Elisabetta M Zanetti, and Ghulam Sarwar Shaikh for your suggestions
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