I am planning to perform a laser ablation experiment on Ar diffused quartz in different depths, creating free Ar molecules which I need to capture instantaneously using a vaccum pump. But cant understand how should I design the experiment, and how much power the vaccum pump should have. Would really appreciate if I can get some suggestion.
Hi,
Based on the info provided in the question, it seems that you will be probably characterizing the collected Ar molecules. Even if that is not the case, for this entire experiment to carry out, you would need to produce initial vacuum for laser ablation of quartz target. If there is no budget constrain, you can go for some medium power turbo molecular pump (TMP) with a small rotary pump as the backing to TMP. Now even if you could ablate the target, you cannot simply capture the Ar molecules by using a vacuum pump alone. At the time of ablation process, the Ar atoms will get ionized due to interaction of laser light energy with them. If possible try to use electric and magnetic fields (engineer a design for your vacuum system) to channel the ionized Ar atoms to a desired location inside the vacuum chamber and then collect them when they get neutralized in it. It is similar to that of separation and collection of Uranium isotopes U235 from U236 by mass spectrometry type of process.
Regards
Hi Amit Morarka,
Thanks a lot for your suggestion. Actually we have started a new project for which I am planning to inspect a quartz sample to measure Diffused Argon (Ar) concentration at depths as small as 100 angstrom (depth profiling). Can you suggest whether it is possible to measure atomic concentrations of gases (i.e., Ar) as small as 107 or 108 atoms/cm3 (ppb) using Mass spectrometer? If so, which specific Mass Spec (i.e., SIMS) would be suitable? If not, what are the other options for such small measurements??
You can consider some kind of residual gas analysers for detecting very small amounts of argon. It may be on the base of the built-in quadrupole mass-spectrometer technology. Please see the following link for exhample: https://www.hidenanalytical.com/wp-content/uploads/2016/06/RGA_Series_Widescreen.pdf
Please also take in account that all atoms including Ar may form clasters being ablated under very high vacuum conditions. So your mass spectrometer residual gas analyser should have adequate mass range to detect the majority of clasters of various mass formed.
In the light of above discussion important fact is that detection system should be much sensitive as to detect a very small amount of Ar gas as a result of laser induced ablation.
- Badges
- Science topic
- Similar topics
- Social Psychology
- Attitude