_
“
EXPERIMENT 11—2
-
.
255
thoron, in turn becomes thorium A5 a solid, whose particles are
positively charged and may be collected’on a negatively charged
_
metal plate P.
110 volts may be used.
Precautiom.——(1) The active material should not be left in
the cup for extended periods of time (weeks_or months), as it
,
is usually prepared in slightly acid form… Store the material in a
‘
Il…”…
_
:
a
a
-
-
°
?
?
'
f
f
‘
l
l
-
/ŒWŒÊ
Illjlll
_
.
“?
;////////1æW///AIËI@ _ .
-
…
,
FIG. 11—7.
Thorium C apparatus.
glass tube. (2) It is impemz‘ive that the instrument be kept away
from électroscopes, electrometers, etc., since the thoron Will dis—
tribute itself throughout ‘the room and addgreatly to theirhatural
leak.
Do not store the active material With these instruments
and do not use. it in thesame room.
‘
_
’
'
‘
Experiment—1. Prepare an alpha ray electroscope and meaSure
its natural leak.
…2. Thoreughlÿ clean the
of the apparatus of
gure 11—,7;
ne grade of
_
sandpaper on the post, the Clips -andgthe‘under side of the lid.
Clean With*alcohol
clean cloth. This is
to prevent ContaminationgoftheplatePand fis Very“ important.
3; Plaée a freshly sandpaperedcopper plaçè1;(P) lfllth€ ;electroscope
and observé that 1t 1s freefromradmactwe contaminations.
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