Similar approach (looking for slow electrons > 0.25 sec traverse times) for seeing what positrons from a picocurie of positron emitter like Na-22 do in a meter long vertical evacuated tube do?
> [Original Message] > From: Frederick Sparber <[EMAIL PROTECTED]> > To: <[email protected]> > Date: 4/14/2006 5:28:36 AM > Subject: Re: Electrogravity & Proton Repulsion of Electrons > > Michel wrote. > > > > > Measuring the time-of-flight of the electrons from flash to detection > > > at the top/electrometer to determine/prove gravity repulsion might be a > > > chore > > > > You're right Fred, what would be needed is not an electrometer maybe > > (mechanical stuff with inertia isn't it?) > > > > What would you think of the following setup: > > > > - Grounded photo-cathode at the bottom of the tube > > > The S1 (Cs-CsO- on Ag) Photoemissive surface is the one with the > photon peaks at ~ 330 and ~ 800 nanometers with a threshold of about 1254 > nm (1.0 eV IR) > Cr YAG Laser? > > http://ssd-rd.web.cern.ch/ssd-rd/Pad_HPD/Principle/photocathodes.htm > > 0.1 eV electrons have a velocity v = (0.1* 2*1.6e-19/9.1e-31)^1/2 = > 1.875e5 meters/sec! > Electron space charge will act as a "velocity filter" that allows the > higher energy electrons > out, but if there is a repulsive gravity force F(gr) = m*g = = 9.1e-31*9.8 > = 8.9e-30 newtons on an electron > and the restraining electric field (E volts/meter) > force F(e) = E*q = 1.6e-19 newtons at E = 1.0 volt/meter, there is a > problem. :-) > > > > - Grounded grid at the top of the tube (so tube is fieldless) > > > Sounds like a Faraday cup approach, Michel. > > > > - Plate above the grid connected to positive terminal of a low voltage > power > > supply whose negative terminal is grounded. > > > > Time of flight would be time between laser flash and power supply current > > pulse wouldn't it? > > > Yes. But the ~ 5 microseconds/meter 0.1 eV electrons get there ahead of > the S - 0.5 * a* t^2 ~ = 3.0e-10 meters gravity repelled electrons > traveled. > OTOH. if you light pulse it and wait for the "slowpokes" ? > > Fred > > Michel > > > > P.S. Nice applet indeed! > > P.P.S. No I know nothing about vacuum tubes (was born in 57) > > > > > > ----- Original Message ----- > > From: "Frederick Sparber" <[EMAIL PROTECTED]> > > To: <[email protected]> > > Sent: Friday, April 14, 2006 3:56 AM > > Subject: Re: Electrogravity & Proton Repulsion of Electrons > > > > > > > Michel Jullian writes. > > >> > > >> Ingenious! (Faraday cup and saucer, indeed ;) > > >> > > > Very British for tea, what? :-) > > >> > > >> For electrons slow enough not to produce secondary emission I would > have > > >> thought a simpler collecting device, not a hollow one, would work: a > grid > > >> surrounding a solid conductor, the latter positive wrt the former. > > >> > > > In vacuum tubes (if you are old enough to remember them) > > > they call that the suppressor grid, usually tied > > > internally to the cathode. > > >> > > >> For the ultra-low energy emitter photo-emission should work better than > > >> thermo-emission as it will give more homogeneous energies (precisely > > >> controlled by incident light wavelength aren't they?) > > >> > > > I think an LED/or laser could cause low energy-low velocity electron > > > emission from a low work function photo-emissive material. > > > > > > One of Walter Fendt's applets for materials: > > > > > > http://www.walter-fendt.de/ph14e/photoeffect.htm > > > > > > Measuring the time-of-flight of the electrons from flash to detection > > > at the top/electrometer to determine/prove gravity repulsion might be a > > > chore > > > > > > Fred > > >> > > >> Michel > > >> > > > > > > > > > > >
