3B Scientific Teltron Dual Beam Tube D - Manual

3B SCIENTIFIC® PHYSICS
1
Dual Beam Tube D 1000654
Instruction sheet
12/12 ALF
1 2 5 6 9 7 3 4 8 8
1,2 4-mm sockets for filament
and cathode
3 4-mm plug for connecting
anode
4 4-mm plug for connecting
plate
5 Axial electron gun
6 Perpendicular electron gun
7 Deflector plate
8 Boss
9 Fluorescent
screen
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
D (1008507).
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 parameters.
When the tube is in operation, the terminals of
the tube may be at high voltages with which it is
dangerous to come into contact.
• Only change circuits with power supply
switched off.
• Only exchange tubes with power supply
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 dual beam tube can be used to determine
the specific charge e/m from the diameter of the
path followed by electrons fired into the tube
from a perpendicularly mounted gun with a ver-
tically aligned magnetic field and observation of
the spiral path followed by electrons fired axially
into a co-axial magnetic field.
The dual beam tube is a partly evacuated elec-
tron tube, filled with helium at low pressure and
equipped with both axial and perpendicular elec-
tron guns. The electron beams are perpendicu-
lar to one another and a common deflector plate
is provided for both guns. The electron beam
source is an oxide cathode heated indirectly via
a heating coil. The electron paths show up as a
fine, slightly greenish beam due to impact exci-
tation of the helium atoms.