40 likes | 69 Views
Characterization Update. Slade J. Jokela. Repairs/Upgrade still underway. Ar + Gun is still out of commission Should receive part by Monday Borrowed another power supply from Bob Will give finer precision control over electron beam current Will see if lower beam currents are possible
E N D
Characterization Update Slade J. Jokela
Repairs/Upgrade still underway • Ar+ Gun is still out of commission • Should receive part by Monday • Borrowed another power supply from Bob • Will give finer precision control over electron beam current • Will see if lower beam currents are possible • Scan of parameter-space for beam current is currently under way. • Necessary to determine constant-current parameters
Malter Effect • Field Emission • When electron beam is removed from sample, “secondary emission” continues • Sample is negatively biased (~200V, though this is still seen at lower potentials) • See video on blog for observation of emission (sorry if you can’t view video) or http://www.youtube.com/watch?v=jf7BBp1TP1I • Sample was placed in front of LEED screen • Will determine if this is indeed Malter Effect and how much it affects my secondary electron yield results
Continued Work • Expect to be able to measure 1nA with new setup • Will know by the end of the week • Chamber still needs to be opened, but am waiting for repair parts to arrive • Will retrieve ‘lost’ samples at that time