3B SCIENTIFIC U192001, Инструкция

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28 Circuit breaker for mains supply
29 Circuit breaker for high voltage supply
30 Mains voltage selector switch
31 Ventilation grille
32 Mains socket
4. Description
The X-ray apparatus allows you to undertake a wide
variety of experiments on the following topics:
•
Properties of X-rays:
Penetration by X-rays
Straight-line propagation
Ionisation
X-ray photography
•
Fluorescence
•
Shielding from X-rays
•
Absorption experiments
•
Distance law
•
Dosimetry and radiation protection
•
Refraction of X-ray beams:
Laue imaging
Debye-Scherrer imaging
•
Bragg reflections
Duane-Hunt displacement law (determination of
Planck's constant h)
•
Moseley's law
A horizontal counter tube goniometer is built into
the X-ray apparatus that consists of a pivoting meas-
urement arm with a sample holder on its axis of
rotation. The arm takes the form of a magazine for
photographic slides and can also accommodate a
Geiger-Müller counter (U19201), an ionisation cham-
ber (U19208) and various experimental equipment,
either in the shape of slides or mounted on a 50 mm
x 50 mm baseplate (e.g. U19205, U19206, U19207).
The pivoting arm can be turned by hand around the
sample holder or can be coupled to a fixed angle at a
2:1 ratio for experiments on Bragg reflection, for
example. The space where the experiment takes
place is inside a closed housing with a transparent,
radiation-proof cover. The cover has a safety lock
that prevents it from being opened until the high-
voltage ON/OFF button has been switched to OFF and
a delay of 2 seconds has elapsed for the decay of the
high voltage. A timer for a period of up to one hour
allows you to set up long exposures and means that
the equipment does not continue operating for long
periods without supervision. The highly evacuated X-
ray tube with its directly heated tungsten cathode
and copper anode is made of borosilicate glass with
a concave, thin-walled exit window. A leaded glass
cover with a brass collimator allows the X-ray beam
to exit parallel to the top of the apparatus and pre-
vents any scattered radiation from escaping. The
emitted X-ray beam strikes a lead-aluminium screen-
ing plate bearing a radiation symbol of the same
diameter as the uncollimated X-ray beam