Mass Spectrometry



Mass Spectrometry Graph 4.3k gif

I.M.H.O. the Mass Spectrometer is the most useful instrument ever invented for anyone involved with vacuum systems. The graph at the head of this page was made with an ancient,much modified VG Micromass partial pressure analyzer that also has seen service as a leak detector.

Sharp eyed readers have also noted that there is a leak in the system indicated by the mass 32 peak. It was due to a bad weld and didn't show up until after bake-out.

Recent Developments:

Dr. Steve Taylor, of Liverpool University, recently recently gave a talk here about his work building a quadropole vacuum gas analyzer with MEMS technology.

Some hastily scribbled notes:

  1. A quad built entirely on silicon chips-

  2. Disposable due to low costs and the ability to make in batches.

  3. Filters can easily be paralleled.

  4. Small physical size (2 cm quad rods, rods are low cost fiber)

  5. 6 Mhz. instead of 2 Mhz. Working on 10 Mhz.

  6. Usable at high pressure, the limit is around 20mm. Hg due to mean free path limitations.

  7. Filters have been built and developed. Resolution and peak shape is being improved but already approaching that of currently available units.

  8. A cold cathode source that can be produced on a substrate is under development, i.e. a totally integrated MFS Mass Spec..

February 20, 2000

"...We are still very active on this project and have a paper in JVST B coming out in March/April 2001 and a further talk at the IVC in San Francisco later this year....." e-mail from Dr. Steve Taylor"

An MS Word document on "The World's Smallest Mass Spectrometer" may be downloaded from this link.

Links:

  1. The University of Liverpool Department of Electrical Engineering and Electronics
    Look for 'Si & Si/SiGe MOS Devices Utilising Low Temperature SiO2 Insulators' under 'Solid State Electronics Research Group'

  2. Micropower Impulse Radar developed at Lawrence Livermore National Laboratory (LLNL). The MIR is a similar concept to the 'Mass spectrometer on a Chip' mentioned above but is at a higher state of development. A portable, very low cost mine detector is under development in addition to some existing applications.

  3. Micromass

  4. The Secondary Ion Mass Spectrometry (SIMS) Home Page is a new, interactive site with a growing number of user's tips and techniques.

  5. Spettrometria di Massa di Ioni Secondari || University of Padova Physics Department (In Italian)
    (Secondary Ion Mass Spectrometry)
    Copy and paste http://www.padova.infm.it/sims/simsp1 and try the Altavista Translation Service if you don't speak Italian.

  6. Stanford Research Systems RGA page includes a free downloadable demo. We bought an RGA100 some time ago and had the unit up and running in a very short time.

    A typical RGA100 analog scan from a small, lightly baked vacuum systm in our lab is here (38 kb jpeg)



  7. Wiley's Base Peak "The Web's Most Comprehensive Mass Spectrometry Resource" , edited by Kemit Murray.
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