3B Scientific Geiger-Muller Counter Tube User Manual

3B SCIENTIFIC® PHYSICS

Geiger-Müller Counter Tube U8533430

Instruction sheet

07/07 SP/ALF

1 Handling rod 2 BNC socket 3 Supporting clip 4 Housing 5 Protective cap

1. Safety instructions

If too high a voltage is applied, the life of the counter tube will be reduced and its characteristic curve will be altered (the gradient of the plateau will increase).

• Do not apply a voltage higher than 600 V.

The mica window is only 0.03 mm thick and is subjected to the external atmospheric pressure.

• Caution! Do not touch the mica window.

• Replace the protective cap after each use.

The glass seal of the counter tube is not resistant to impacts and pressure.

• Do not subject the tube to knocks.

• Handle the counter tube especially carefully

when it is taken out of its supporting clip.

2. Description

The Geiger-Müller counter tube is a halogen selfquenching trigger counter tube for the detection of

α-, β-, γ- and X-radiation. The counter tube consists of a chromium steel cylin-

der that is filled with an argon-neon mixture together with a halogen gas as a quenching agent. It is closed at one end by a very thin mica window and at the other end by a glass seal, both of which are gas-tight. A thin wire (the counter wire) is arranged axially in the cylinder, which it enters through the insulating glass seal. The counter tube is contained within a metal housing that is fitted with a shielded connecting lead and a BNC socket. A handling rod is attached to the housing by a detachable clamp. The mica window is protected by a removable plastic cap.

3. Technical data

Filling gas: Neon-argon mixture,

with halogen as

quenching agent Cathode dimensions: 39x14 mm² Window: Mica, 9 mm Ø Surface density: 1.5 – 2.0 mg/cm² Operating voltage: 400 – 600 V (recom-

mended voltage: 500

V) Rel. gradient of plateau: 0.04%/V Dead-time: 90 µs

Limiting resistance: 10 MΩ, built into the

housing Overall dimensions: Approx. 85 mm x 25

mm Ø Handling rod dimensions: 100 mm x 10 mm Ø Mass: Approx. 160 g

4. Operation

Note:

The protective cap does not allow α-radiation to pass through, and transmits β-radiation only partially.

Remove the protective cap when appropriate before starting measurement. Replace the cap after each use, taking care not to touch the mica window.

For carrying out experiments the following additional equipment is recommended:

HF cable, 1 m U11255 Digital counter (230 V, 50/60 Hz) U8533341-230

or Digital counter (115 V, 50/60 Hz) U8533341-115

Geiger-Müller box U11391

• Connect the Geiger-Müller counter tube to a

digital counter through an HF cable.

• Set up the counter tube so that the radiation falls

squarely on the mica window.

• If appropriate, remove the plastic protective cap.

• Set the required measurement time on the

counter.

• Switch the audible counting signal on or off as

required.

• Start the measurement.

• After the measurement, replace the protective

cap.

10 M

1 M

220 pF

400 V... 600 V

Fig. 1. Schematic arrangement of the counter tube.

Elwe Didactic GmbH • Steinfelsstr. 6 • 08248 Klingenthal • Germany • www.elwedidactic.com

3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany • www.3bscientific.com

Subject to technical amendments