How does beta radiation behave in a magnetic field? RE 2.5

How does beta radiation behave in a magnetic field?
Object
To determine if beta radiation is deflected in a magnetic
field.
Materials
Base plate for radioactivity
Counter tube holder on fix. magnet
Source holder on fix. magnet
Plate holder on fix. magnet
Defl. magnets f. plate holder, 2 pcs
Counter tube, type B
Geiger-Müller Counter
Source Ra-226, 3 kBq
09200.00
09201.00
09202.00
09203.00
09203.02
09005.00
13606.99
09041.00
1
1
1
1
1
1
1
1
Set-up and procedure
Fig. 1
— Fix the deflecting magnets to the plate holder with the
milled screws. The distance between the two magnets
should be 2 cm.
— Position the plate holder on the base plate so that the
centre points of the deflecting magnets are immediately above the centre point of the angular scale.
— Insert the source of radiation in the source holder.
Place the source holder in front of the plate holder and
slide the source of radiation until its exit opening is in
front of the deflecting magnets. Now remove the plate
holder from the base plate, without displacing the
source of radiation.
RE
2.5
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— Position the counter tube holder on the base plate so
that the tip of its positioning marker points at the intersection of the 0° angle division and the semi-circle of
radius r = 5 cm.
— Insert the Geiger-Müller counter tube in the counter
tube holder and move it until the counter tube window
is directly above the tip of the positioning marker.
— Connect the counter tube to the counter and select
60 s for the time of measurement.
— Carefully remove the protective cap from the counter
tube, switch the counter on and start the first measurement procedure with the “Start-Stop“ button.
— Enter the first count rate in Table 1.
— Move the counter tube holder to the 10° graduation on
the angular scale; making absolutely sure that the distance of the counting tube from the source of radiation
does not change and that the axis of the counter tube
is exactly aligned along the angle graduation. Start the
next measurement and enter the count rate in Table 1.
— Repeat this measurement with all of the angles from
+ 90° to -90° listed in Table 1.
— Place the plate holder with the deflecting magnets on
the centre point of the angular scale.
— Determine the count rates for all listed angles as
before, but now with the deflecting magnets in position. Enter the count rates in Table 1.
— Repeat the measurement series after having transposed the magnets in the plate holder.
— Repeat the measurement series with the deflecting
magnets at a different distance.
Fig. 1
Phywe Series of publication • Student Experiments Physics • Radioactivity • PHYWE SYSTEME GMBH • D-37070 Göttingen
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2.5
How does beta radiation behave in a magnetic field?
Results
Table 1
Angle in degrees
without magnets
with magnets
magnets transposed
magnets closer together
C
C
C
C
counts/60 s
counts/60 s
counts/60 s
counts/60 s
0
+10
+20
+30
+40
+50
+60
+70
+80
+90
-10
-20
-30
-40
-50
-60
-70
-80
-90
Evaluation
1. Enter all of the measured values in the functional diagram, Fig. 2. Use different coloured pencils or markers for the
values obtained with and without the deflecting magnets. Draw separate connecting lines through the measured values of each of the measurement series.
2. Draw a line in each of the resulting curves to show the direction in which the highest count rates were obtained.
Fig. 2
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Phywe Series of publication • Student Experiments Physics • Radioactivity • PHYWE SYSTEME GMBH • D-37070 Göttingen
How does beta radiation behave in a magnetic field?
RE
2.5
S
3. Which effect do the magnets exert on the movement of the beta radiation?
4. Compare the experimental results with the behaviour of a conductor carrying current in a magnetic field.
5. Which influence does the distance between the magnets have on the deflection of the beta radiation? Explain this
observation.
Phywe Series of publication • Student Experiments Physics • Radioactivity • PHYWE SYSTEME GMBH • D-37070 Göttingen
13056
49
S
RE
2.5
How does beta radiation behave in a magnetic field?
Space for notes
50
13056
Phywe Series of publication • Student Experiments Physics • Radioactivity • PHYWE SYSTEME GMBH • D-37070 Göttingen

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