3B SCIENTIFIC PHYSICS 1023094 빠른 시작 매뉴얼 - 페이지 2

{카테고리_이름} 3B SCIENTIFIC PHYSICS 1023094에 대한 빠른 시작 매뉴얼을 온라인으로 검색하거나 PDF를 다운로드하세요. 3B SCIENTIFIC PHYSICS 1023094 6 페이지. Franck-hertz tube with hg filling and heating chamber

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The Franck-Hertz tube contains mercury.



If the glass breaks and mercury escapes,

make sure to observe safety regulations re-

lating to the handling of mercury.

2. Description

The Franck-Hertz tube with its mercury filling is

used to demonstrate the quantised release of en-

ergy by free electrons colliding with mercury at-

oms and to determine that the excitation energy

for the mercury resonance line (6

eV.

Franck-Hertz tube attached to front plate

The Franck-Hertz tube is a highly evacuated elec-

tron tube containing mercury with its electrodes set

up in parallel planes. The electrodes consist of an

indirectly heated oxide cathode, an anode grid and

a collector electrode. In order to increase the like-

lihood of collisions, the distance between the an-

ode and cathode has been made large (8 mm) in

comparison to the mean free path in a mercury at-

mosphere (for a temperature of approx. 180°C).

By contrast, the distance between anode and col-

lector is small. An earth ring is located level with

the anode grille to prevent disturbance due to

background radiation. The tube is mounted on the

front plate of the heating chamber and can be re-

moved or exchanged. The front plate also has ce-

ramic-insulated sockets and a schematic diagram

of the tube. The Franck-Hertz tube is mounted in

such a way that the whole tube and its connecting

wires can all be maintained at constant tempera-

ture. This is necessary because the density of the

mercury vapour is always determined at the cold-

est point of the tube. Leakage currents resulting

from radiation due to ion conduction in the hot

glass walls are prevented by a protective sintered

alumina ring. A fixed attenuating resistor (10

inserted between the sockets for the accelerating

voltage and for the anode of the tube. This protects

the tube in the event of excessive voltage occur-

ring due to arcing. The voltage drop across this re-

sistor can be neglected when measurements are

being made.

Heating chamber

The heating chamber serves to establish the va-

pour pressure inside the Franck-Hertz tube with its

mercury filling and helps you carry out experiments

with a sodium fluorescence tube (1000913).

It consists of a powder-coated sheet steel casing

with two viewing windows. The front plate is at-

tached via six knurled screws. The chamber is

heated via a tubular heating element in the cham-

ber floor. Temperature measurement and regula-

tion is carried via an integrated micro-controller

and a PT 100 thermocouple. A digital tempera-

– 6

) is 4.9

ture display allows you to read off the tempera-

ture set-point and the actual temperature value.

The "SET" button can be used to toggle the dis-

play between ° Celsius and ° Fahrenheit. The "+/-

" keys allow you to set the set-point for the tem-

perature in steps of 1 K. There is an opening at

the top with a spring clip for holding a thermometer

and a thermally insulated carrying handle.

The apparatus 1023094 is for operation with a

mains voltage of 115 V (±10%), and the unit

1023095 is for operation with a mains voltage of

230 V (±10%).

2.1 Scope of delivery

1 Franck-Hertz tube with mercury filling mounted

on front-plate

1 Heating chamber without front plate

1 Instruction sheet

1 Power switch

3 "SET" button

5 "+/-" buttons

7 Knurled screws

9 Cathode socket

11 Anode socket

13 Heating chamber

15 Handle

2 Operating display

4 Display

6 Thermal insulation

8 Front plate with Franck-

Hertz tube attached (not

shown)

10 Tube filament socket

12 BNC socket for signal

output

14 Spring clip for thermom-

eter