Additional thought, the protective film itself could also be made of CR-39 (which could be of the same batch, milled down to a few microns thickness), this would guarantee that the cathode lies on exactly the same substrate as in a non-PACA experiment.
Michel 2009/9/10 Michel Jullian <[email protected]>: > 2009/9/10 Abd ul-Rahman Lomax <[email protected]>: >> At 03:45 PM 9/9/2009, you [Jed] wrote: > >>> Ah. CR-39 is opaque. You mean looking around it, from another angle. >> >> No. There are different kinds of CR-39. It's true, I've never seen a CR-39 >> chip as used in this field, personally, > > See in top photograph here > http://www.earthtech.org/CR39/A_B/reportAB.html the cathode wire > bearing part with a "1" and an "A" scratched in it. Doesn't look very > opaque to me, at least not in the visible spectrum (Jed, can you > provide refs showing opaque CR-39 used in this field?) > > Suggestion, if you want to video the cathode, better look at it from > the side, I gather deposits can form on the bottom. Videoing through > the CR-39 seems a good idea to me, if nothing else it will show how > the plating, dendritic or spongy, forms vs time (hard dendritic > plating is a requirement for pit forming it seems). > > You could drill a round window through the flat side wall of the cell, > and press the cathode bearing CR-39 against the wall via e.g. a PTFE > gasket around the hole to prevent leaks. Note such an arrangement also > allows "PACA" experiments by interposing a few microns mylar film, > plus, I suggest, a thin layer of air guaranteeing no electrolyte vs > CR-39 chemical interaction whatsoever while only negligibly slowing > down energetic particles. > > Michel >
