.
EXPERIMENT (10—1)
7
237
'
EXPERIMENT 10—1
’
POSITWE RAY PARABOLAS
Âppamtus.—Figure 10—12 shows one form of apparatus which
may be used to study positive ray pàrabolas. It is drawn to_scale.
The
(Æ) consists of a hollow cone made of molybdenum or
tungsten to withstand the heat developed by electron bombard—
ment at this point. The pyreX discharge tube (8) is 5 centimeters
in diameter and about 50 centimeters long._ The cathode (Q) is
'
made of steel and has a circular groove into which the discharge
-
tube is waxed.
The edges of this groove must be rounded‘ to =
,
'
P
'
*
.
A
Î
-
C
Î
Î
Î
\
…
{0
‘
‘
=
_
+
\
_
,,
_
_
‘
FIG. 10—12.
ï
Pre—vent electricalbreakdownof’theglassWatercqong î‘s PfO—
"
vide—byi'arsmgleturnofcoppertubmg00œldeœd af°üd
the
.
‘
’
’The canal(K) con51sts ofahole14mrlhmeteïsln diameter
,
and-' 5 ‘to' 74
to a brass
_
Ïî
wh1chlsdnlledaXlaÿf0fthePassage ‘Of
PdSÏ-_
latefr0mthebrasscrhnderbycmularhardmbb€fwaShelsand
.
"
arewaxedmplaœAsheetOfmlcamthemagnetlcarcmtseweS ‘
-‘
tomsulatethepdepæœsfr@meachtherelecmœuyThenthe
Ÿ
_
11@veltdchnevarwdw1thasheWlreP0tentlometerïsused?°
‘
.