Instruction Sheet - 3B SCIENTIFIC PHYSICS 1000651 Mode D'emploi

3B SCIENTIFIC ® PHYSICS
Electron-Beam Deflection Tube D 1000651

Instruction sheet

10/15 ALF
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10 9 8 7 6 5 4 3 2
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1. Safety instructions
Hot cathode tubes are thin-walled, highly evacu-
ated 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 cath-
ode is at the wrong temperature, it can lead
to the tube becoming destroyed.

Do not exceed the stated operating parameters.

Only change circuit with power supply equip-
ment 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.

If necessary, allow the tube to cool before
dismantling.
7 6
3 4 5
The compliance with the EC directive on electro-
magnetic compatibility is only guaranteed when
using the recommended power supplies.
2. Description
The electron-beam deflection tube is intended for
investigating the deflection of electron beams in
electrical and magnetic fields. It can be used to
estimate the specific charge of an electron e/m
and to determine the electron velocity v.
The electron-beam deflection tube comprises an
electron gun which emits a narrow, focussed rib-
bon of cathode rays within an evacuated, clear
glass bulb. A tungsten 'hairpin' filament hot cath-
ode is heated directly and the anode takes the
form of a cylinder. The deflection of rays can be
achieved electrostatically by means of a built-in
plate capacitor formed by the pair of deflection
plates or magnetically with the help of the Helm-
holtz coils D (1000644) magnetically. The cath-
ode rays are intercepted by a flat mica sheet, one
side of which is coated with a fluorescent screen
and the other side of which is printed with a cen-
timetre graticule so that the path of the electrons
can be easily traced. The mica sheet is held at
1
1 Fluorescent screen
2 Lower deflection plate
3 Boss with 4-mm plug for
connecting deflection plates
4 Electron gun
5 4-mm sockets for connecting
heater supply and cathode
6 4-mm plug for connecting
anode
7 Upper deflection plate