3B Scientific Teltron Critical Potentials Tube S with He-Filling - Manual

3B SCIENTIFIC ® PHYSICS
1
Critical Potentials Tube S with He-Filling 1000620
Instruction sheet
08/13 ALF
1 BNC
jack
2 Glass coating at the
anode voltage
3 Collector ring
4 Anode
5 Electron
gun
6 Heater filament
7 Connection pin anode
8 Connection pin filament
9 Guide
pin
10 Connection pin cathode
1. Safety instructions
Hot cathode tubes are thin-walled, highly
evacuated glass tubes. Treat them carefully as
there is a risk of implosion.
• Do not subject the tube to mechanical
stresses.
• Do not subject the connection leads to any
tension.
• The tube may only be used with tube holder
S (1014525).
If voltage or current is too high or the cathode is
at the wrong temperature, it can lead to the tube
becoming destroyed.
• Do not exceed the stated operating parame-
ters.
• Only change circuits with power supply
equipment switched off.
• Only exchange tubes with power supply
equipment switched off.
When the tube is in operation, the stock of the
tube may get hot.
• Allow the tube to cool before dismantling.
The compliance with the EC directive on elec-
tromagnetic compatibility is only guaranteed
when using the recommended power supplies.
2. Description
The critical potentials tube S with helium filling is
for quantitative analysis of inelastic collisions
between electrons and helium atoms and serves
to determine ionisation energy and excitation
energies of helium, to solve primary and spin
momentum quantum numbers and to demon-
strate metastable states.
The critical potential tube features an electron
gun with a directly heated tungsten cathode and
a cylindrical anode in a glass bulb, evacuated
and then filled with helium. The inner wall of the
bulb is covered with a conductive coating con-
nected to the anode. The collector ring is situ-
ated inside the bulb in such a way that diverging
electron beams cannot directly collide with it.
The battery unit provides a (decelerating) collec-
tor voltage V
R
between the anode and the col-
lector.