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Патент USA US2406276

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All@b 20,1946.v
2,406,276
G. M._wHlTE
_ELECTRIC DISCHARGE DEVICE
'F'uedùom 13, 1942 '
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George M
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H is Attorney.
l2,4116,,276
Patented Aug. zo, 1946
George M. White, Schenectady, N. Yi, assignor' to
General Electric' Company, a corporation of
New York .
Application November 13, 1942, Serial No. 465,401 ' Y
s claims. »f (o1. 25o-27.5) _ `
,Y
1
My invention relates to electric discharge de
vices, and more particularly to the construction.
of space resonant electric discharge devices of the
of metalfor material thereonfandan appropri- ' ’
magnetron type.
reduce the probability of an arc-over between the
ately `positioned and designedY insulator having a
long leakage path is employed to eliminate’or
In the widespread use of electric discharge
electrode structure and the associated magnetic
devices of the magnetron type, it is important
pole pieces.`
that there be a desired symmetry of elements,
' For a better understanding of‘my invention,
Y.
Y
.
_
Y
or‘ electrodes, in order to obtain uniform _ener
reference may be had to the followingy descrip
' gization of associated space resonant regions, or
cavities, Without sacrificing the power output of
tion takenin connection with the accompanying
draw-ing, and its scope will be pointed out in the
the device »by a construction which lcauses the
appended claims. Fig. 1 Ídiagrammaticallyl illus
establishment of inordinately high voltage gradi
ents across insulating parts of thestructure which
trates` an embodiment of my invention as applied
would require a reduction in the nominal power
type employing a metallic envelope or vcontaining
to: an ultra high frequency magnetron >of, the '
` output, or cause damage to the elements, or elec
member and >which includes a pair of permanent- Y
trodes, of the discharge device, thereby necessi
tating its withdrawal from use.
View of the~anode structure, *andFigB is a de- ,
It
new
It
vide
vice
ly magnetized ñeld members.V Fig.,2 is a detailed
tailed view ofthe suspendingand vcentering in
is an object of my invention «to provide a
and improved electric discharge device;
is another object of my invention to _pro
a new and improved electric discharge de'
of the magnetron type.
sulatorand‘cathode construction._
.
_
Y
_
Fig. 1 of the accompanyingdrawing _diagram
matically illustrates anfembodirnent- of my inven
tion as applied to an eleotric‘discharge device
o'f _the magnetron type employing a pair of mag
I_t is another object of my invention to provide
-netic field pieces oppositely disposed relative to a ,
new and improved structure for supporting the
elements of a magnetron of the space resonant
centrally located anode structure including a
space _resonant cavity, orcavities; andFig.' 2 'is
type which permits operation of the device at rel
atively high voltages, and which does not disturb
the desired symmetry ofthe electrostatic and mag
netic fields required> for-satisfactory operation.
a detailed view of the anode structure.
Referringparticularly to
_ _ _
1, there is shown
an- elongated cylindrical containerthelateral wall '
It is >a still further object of my invention to 30 structure of which is'provided `by a single metal
provide new and improved cathode supporting
structure for ultra high frequency magnetrons
wherein shielding means are provided to prevent
envelope or containing member` I, preferably Ao_f
the deposition of conductive material on associ
The ends Voff-the containerare _enclosed by’fl'anged
_ated insulating structure, »
-~
tubular form, constructedjof a ferro-magnetic
material such as cold rolled steel,` or,the_1_ike,_
35
Briefly stated, in the illustrated embodiment of
my invention, I provide a new and improved ultra
members 2 and 3 which are welded or otherwise
herrmeticallyy joined to the containing member II.
The outerîsurface ofthe envelope orf-member l_
high frequency electric discharge device-of the
may be'providewith. a plurality of heat dissi
magnetron type comprising a space resonant re
gion, orregions, energized in accordance with l
pating‘m’eans such as fins (not shown),
the oscillations, or motion, of the electrons con
stituting the space charge between an anode and
a cathode, and in which the cathode is main
-tained in spaced relation with respect to the
anode structure by means of an improved rigid
The anodestructure comprises a circular mem
ber`which has a relatively large central opening
5 Vand a series of smaller openings r6 Varranged
symmetrically about the central opening 5. The
cableconstruction, which affords rigid position
central opening ris joined tothe openingsjs Aby
means of, a plurality ,of radially-_extendingslots 1.
ing of the cathode without entailing the estab
lishment of excessively high voltage gradients
across the insulating parts and which, by virtue
of its symmetry, does not materially disturb the
magnetic or electrostatic ñelds required for the
- , The anode structure 4, which preferably con
50 sists of copper, >issupported by being brazed to
the interior Wall surface of member I. To facili
tate thebrazingl operation,- small `channels 8 are
cut into the outer periphery of the structure 4,
most effective operation of the device, or system.
In addition, shielding means are positioned rela
tive to the cathode and the insulating structure
to prevent the establishmentof aconductive layer
_
Within the containing member l and approx
imately at its central region there is provided an
anode structure 4 `shown in plan view in Fig. 2.
55
and. these areoused to receive rings of Ybrazing
material applied before the anode _structure is `
energy factor. One of the materials which may
y ,K inserted within the containing member I. A rela
tively-large circumferentially extending channel-Y
VI) serves to reduce .the overall weight of the struc
ture.>
`*
'
.'
f beY used for this purpose is that class of 'alloys
including aluminum, nickel and'cobalt.> Alloys
of this type are described, for example,Y in thev
'
Within the central opening '5 of the anode
structure, I employ an indirectly heated cathode
Mishima Patents No. 2,027,994 to No. 2,028,060.
As a means for providing a low reluctance con
comprising a sleeve Iû, of nickel or other suitable
' nection between the base endsof the `magnetic
pole pieces I6 and I'I, the pole pieces may be re
material, havingfñan'gesj I and l2 at the ends,`
spectively seated upon relatively 'thick disc-like’
thereof. This sleeve, >which may be coated ex
ternally with a suitable »activating material such _
members I8Y and I9 constructed of ferro-mag
as barium oxide, contains a ñlamentary heating Y
netic material, such as steel. For the purpose of
element I3 by which the sleeve Il] may be» main-tained at an electron emissive temperature. One
ïsecuringthe pole pieces rigidly to the discs I8
and I9, I may employ clamping rings 2i? and ZI
end of the cathode sleeve lil is closed by a/ínetal
slippedfover the pole pieces and welded to the
disc I4 and the'other end of the sleeve is closed
discVV members. „
by an apertured disc I5.
'
_
'
The desired precise placement of pole pieces I6
’
I VThe discs I4 and I5.have diameters Vof sußicient
‘ and Il with V,reference to the anode structure 4
may AIce_obtained by the use of spacing rings 22
` and 23'.v As will be observed from Fig.,1, each of
these rings is interposed between one surface of
the anode 'structure ZI and ytheV surface ofthe ap
> dimension to substantially shield insulating struc'- _,
ture, to be Ydescribed presently, to prevent. the
deposition of an appreciable conductive layer on
ythe ' surf ace of the , insulators; which , would`V tend
to reduce the operating voltage` of the discharge
ertured discs'24, 25, each disc in Vturn being in
abutment with a properly positioned and formed
du'ctive layer would-tend to` establish relatively
shoulder on the adjacent pole piece as indicated
low resistance leakage paths between elements at 255 at 2S and Z'I. The spacing 'rings 22.»and 23 may
substantially great .differences of potential. ' >In
be welded in place before vthe pole pieces are in
ther operation "of the .electric discharge device a
se'rted within the containing member I.» ’
spacecharge is developed inïthe space between
Pole pieces I6 and I I, inasmuch asethese ele,
the cathode sleeve II) and 'the surrounding anode, Y ` ments are positioned within the containing'mem
device, or the ‘systemes a whole, since the _con
structure ¿I by the'application'of a lsuitable po 30 'ber I,‘ may be employed eis-supporting means for
tentialimpressed between'the cathode structure
the cathode structure. This may-'be done, 'for `
andthe containing member I. The containing
example, by constructing `the pole pieces I6 and
member I, to which the anode structured is di- j
I'I to have alined central openings `cr-centering
rectly connected, may have-impressed> thereon a
channels 28 and 29,Y respectively, preferably` Yof
unidirectional potential, such as'apositive poten
circular cross-section and which extend along
the axial or'longitudinal dimension of the pole
tial„ and the other terminal for the unidirectional
circuit' is connected to the cathode structure .by
apparatus tol be described presently. '
'
and
' pieces
afford
communicating -' channels
through which elements to be described-presently
I
' The electrons which constitute the space ch’arg
extend or are positioned, and which presentV
are given a spiralï'or orbital motion by a magnetic 40 alined openings 36 and 3l in the respective pole
field which is providedby electromagnetic struc
ture, or by permanently‘magnetized ñeld pieces
faces.
'
y
to be describedv presently. >The resultant gyra
Referring to magnetic pole piece I 5f in particu
lar, I provide a relatively rigid concentric-con
„tionsor oscillations of the‘electrons constituting
i ductor construction for supporting the cathode
the space charge produce excitation of the anode
centrally within the enlarged opening 5 .of the
structureV at a Vfrequency which is correlated to
anode structure-4, and which also is employed-,as
the natura-l> frequency'ofthe >space resonant re
gions which is determined by the physical dimen
sions of the openings 6 considered in conjunction
with the slots '1. The function of the anode
a means or conduit for supplying energizing cur
rent to cathode heating element I3. Of course,
structure in this respect may be explained from
one point of View by considering that' it is made
up of a plurality of space resonant regions in’each
50
, one conductor of the cathode is also employed in
connection with an externalcircuit'by virtue'of
which Ya unidirectional potential isvapplied be
Considering
j tween vthe anode and theY cathode.
more specifically the concentric cable-‘construc
of which inductance is provided by a wall surface
bounding one of the circular openings v6 >>vand
tion, I provide-a cable having an inner "conductor
32 and >an vouter conductor, 33, preferablycon
capacitance is provided by the opposing surfaces
structed of a metal such asY nickel or molybdenum,
~ of Yone of theV slots 1. »Assuming this point of view,
it will be seen that the operating frequency is in
and which are'maintained'in spaced relation with
respect to'each other by vacontinuous insulator,
a large measure determined by the dimensions of
the openings 6. -
'
In order to provide a magnetic field of sufñcient
intensity to permit the apparatus to function in `
60
such as a tubular insulator 34.' ` Conductors@
and 33 are connected ,to externallyaccessible
lead-in wires 35 andA 36 which are sealed in yal
its intendedrmanner, there are provided Within
the‘containing member I tapered magnetic pole
suitable insulator, suchV asa vitreous insulator 31.
In order «to facilitate the attachment of the insu
lator 37 to the body of the dischargedevice, and
pieces I6 and I‘I which are directedaxiallyrof the 65 more particularly to the flange member 2, I may Y
containing memberl andmay extend in 'close
employ a cylindrical metallic member 38 which is
proximity to the upper and lower surfaces Yof the
welded or soldered to member 2’ and sealed to
anode structure 4. For presentl purposes, Ythese
conductor 31.
v,
'
_
`
‘_
pole pieces maybe assumed to be permanently Í
I provide within the channelV 23, an insulator
magnetized in such a sense that the north pole 70 39, the details of which are shownïin Fig„3. In-`
of one faces the south pole of the other.
To assure Ythe existence of the magnetic Vfield
o-f the required intensity, the pole pieces I6 and
I__1 should be constructed of a magnetizable sub
sulator 39 Vserves as a supporting and centering
means for the concentric Acable comprising con
ductors 32 and V3.", andv closelylñts- _thefchann’el
wavllrby virtue of the `part 39a thereof ,which
stance >having a high coercive force and a high 75 closely vengages and is fitted to the 'channel wall.
2,406,276
5
6
Insulator 39 is located near the end of channel
28 in the vicinity of the cathode and is provided
with a section 39h of restricted diameter and
which extends beyond the pole face 40 of mag
netic pole piece I6. In order to place and main
tain the insulator 39 in the desired axial posi
tion, I provide a tubular spacing member> 4I in
abutment with the insulator 39 and extending
therefrom to the base of magnetic pole piece I6
where it engages or abuts the disc I8. The mem
.
which may be connected to the concentric trans'
mission line comprising conductors 5I and 52.
'I'he various space resonant regions, or cavities,
are excited or energized in accordance with the
oscillations or motions of the electrons constitut
ing the space charge within the region defined
by the cathode sleeve I0 and anode structure 4.
The period of oscillation .of the electrons con
stituting the space charge, or a portion thereof,
is correlated with respect4 to the natural-reso
ber 4I is closely fitted to the surface of the chan
nance frequency ‘of the various space resonant
`nel wall and serves as a means for preventing
regions comprising openings Ii and slots ‘I to`
undesired axial movement of the insulator 39
maintain the regions in oscillation, and energy
may be derived from all the regions through the
and the associated cathode construction.
Y The
concentric
conductor
also serves
L
as
a
loop 50 and conductors 5I and 52. '
Discs I4 and I5 shield insulators 45 and 39, re
spectively, from the cathode and thereby pre
serves as a means for impressing a potential,
vent the electrons from striking the insulators,
such as a negative potential, on the cathode.
which would otherwise be the case due to the
Conductor 33 may have a flanged part ’42 at 20 axial movement of those electrons which pass
beyond the boundaries defined by the top and
its lower end to engage firmly disc I5, and the
means for supplying current to the cathode heat
ingr element I3, and the outer conductor 33 also
inner conductor 32 may be bent over, as shown
at 43, to prevent undesired axial movement or
stress of the inner conductor relative to the in
sulating member 34 which is interposed between
part 43 and the fianged part 42 of outer con
ductor 33. A spacing ring 44, preferably con
structed of nickel, is placed between insulator 39
and the upper surface of disc I 5, Vall of these
members being in close contact and engagement 30
so that the heat transfer from the cathode to
the insulators 39 and 45 is minimized.
It will be noted that therestri'cted part 39D
of insulator> 39 aiiords an appreciable annular
space between its surface and the wall of chan
nel 28, thereby providing a long leakage path
between the cathode structure and the pole piece
bottom surfaces of anode structure 4. Even
though the sides of the insulators collect any
conductive coating incident to the relatively high
temperature of the cathode”, the increased length
of leakage path will prevent breakdown which
would otherwise result from creepage along the
surface of an improperly positioned and designed
insulator.
'
Another advantage ofthe construction which
I provide is that the insulating paths, particu
larly that of insulator 39, with respect to ground'
>are many times greater than that afforded by
the prior arrangements, and consequentlyfor a
given applied voltage it is possible to use mate
rials having a somewhat smaller dielectric
strength, Furthermore, by virtue of the above
described construction, the tendency to produce
I6. In this manner, even though the conductive
layer tends to be deposited on part 39h of insu
short circuits in the cathode assembly,` is ma- .
lator 39, there is nevertheless afforded a suñi 40 terially decreased since the two terminals or
ciently long leakage path to reduce or minimize’
conductors for the cathode heating element I3
the probability of arc-over between pole piece I6
are well insulate'd from each other and are of
strong mechanical construction.
and the cathode structure.
Some of the other advantages incident to
Within the channel 29 of magnetic pole piece
my above described construction for »the electric
I'I, I provide an insulator 45 which centers the
discharge device include ease of mechanical as
lower end, and particularly disc I 4,'of cathode
sembly made possible by the simplicity of con
construction and supports a metallic pin 43
struction, particularly the single upper insulator
which is turned over at its upper end and to
and the rigid concentric cable. In addition, the `
which the lower terminal 41 of cathode heating
element I3 is welded or soldered.
The upper 50 generally symmetrical configuration ofthe ele- ,
terminal 48 of the cathode heating element is
welded or soldered to the inner conductor 32.
ments, or electrodes, of the discharge device and
the associated conductors and insulators reduces
the possibility of establishing excessively high or
dangerous voltage gradients which would ordi
firmly maintaining the cathode construction and 55 narily tend to be present at the ends of chan
I also employ between disc I4 and insulator 45
a metallic ring, such as a nickel ring 49, for
nels 28 and 29 facing the -anode structure 4.
the insulator 45 in the desired íixed spaced rela
tion and for minimizing heat transfer. Inasmuch
Certain features of the electric discharge de
as insulator 45 is iirmly positioned against the
vice shown in Fig. l, including the metallic con
taining member and the permanently magnetized
wall of channel 29, it will be appreciated that
axialv as well as radial movement of the cathode 60 magnetic iield members, are disclosed and broad
ly claimed in a Ycopending patent application of
construction is prevented.
As a means for Vextracting energy from the
Elmer D. McArthur, Serial No. 447,903, filed June ,
discharge device, I may employ an output elec
22, 1942, and which is assigned to, the assignee
of the present application.` Other features re
trode means, such as a loop 50, extending into
one of the openings 6 and which may constitute 65 lating to> certain aspects of the rigid cable con
an extension of a center conductor 5I of a con
struction are disclosed and broadly claimed in
centric transmission line comprising conductor
5I and an outerconductor 52 which aresealed Y
by means of a glass or vitreous seal 53.
copending patent application Serial No. 465,424
of Ralph J. Bondley, filed concurrently herewith
and'which is also assigned to the assignee of this
Upon the application of a unidirectional volt 70 application.
While I have shown and described my inven
age between the anode structure and the cath
> tion as' applied to a device embodying various
ode, the electric discharge device effects vener
gization of the various space resonant regions,
elements diagrammatically shown, it will be obvi
comprising openings 6 >and slots l, to supply ultra
ous to those skilled in the art; that changes and
high frequency energy to a> utilization circuit 75 modifications may be made without departing
2,406,276
7
.
8.
from my invention,'and I', therefore,- aiminthe
positioned within 'the channel Vof the other pole
appended claims to-fcover all such changesV and
modiñcations as fall Within the true spirit and
tallic pin positionedv by‘said insulator and con
scope of my invention.
nected to the other terminal of said cathode heat
'
~
‘
' What I claim as new and desire to secure by '
piece near'the region of the pole face, and a me- ~
ing'element and said cathode. .
Letters Patent of the United States is:
l. An electric discharge device comprising a
5. An electric discharge device of the magne
tron type comprising o, plurality of enclosed co
pluralityvoi enclosed co-operating electrodes in
operating electrodes including a thermionicicath- .
ode including a cylindrical sleeve coatedowith an
cluding an anode structure having a centrally lo
cated opening therein and -a cathode, a pair of 10 electron emissive material and a cathode heat
magnetic pole pieces positioned on opposite sides
lof said anode structure and each including a
channel lying longitudinally of the pole'piece and v
being alined With respect to each other vand with
respect to said opening', a pair of insulating
means each pcsitioned'in one of said channels
ing element Within said sleeve, an anode> struc
ture of general circular coniiguration provided
with a circularY center opening Within which said
cathode is positioned and including a space reso'
nator to be energized in accordance with the
motion of the electrons constituting the space
charge between said cathode and said anode.
structure', a pair of magnetic pole pieces respec
andv each having a portion engaging 'the walls of
the channel at a regionspaced from the pole
tively positioned on opposite sides of said anode
face anda second portion extending from the
channel beyond the pole face, Vsaid last men 20 structure for establishing a magnetic ñeld Within
the space deñned by said cathode and said anode
tioned portion having a smaller cross section
than the channel, and means extending through
structure and each having therein a channel po
sitioned longitudinally of the pole piece, means
said insulating means supporting and centering
supporting said cathode comprising a concentric`
said cathode.
2. An electric discharge device comprising a 25 cable extending through th‘e channel of one of
said pole pieces and including an inner conduc
plurality of enclosed (zo-operating electrodes in
cluding a, thermionic cathode including a heating
tor, an' outer concentric tubular conductor and
an insulating material therebetween, an insulator
element andan anode structure surrounding said
cathode, a pair of magnetic pole pieces spaced on
positioned in the channel of one of saidpole
pieces and inl close engagement' therewith sup
opposite sides of said. anode structure and each
having therein a channel of circular cross section
porting and centering said cathode', means con
necting one terminal of said cathode >heating‘ele
positioned longitudinally of the pole piece, means
supporting said cathode and for supplying cur-`
ment to said outertubular conductor, means com- .
prising a pin connecting the other terminal of
>rent to said heating element comprising a con
centric -cable construction including an inner and 35 said cathode heating element to said cathode
structure and constituting a part- of an energiz
outer conductor extending through the channel
of one of said pole pieces, an insulator fitted in
ing circuit for said cath'ode heating element, a'
second insulator positioned Within the channel of
the channeloi- said one pole piece centering and
the other pole piece and centering said pin, and
1 ` supporting said cable, and aY tubular spacing
member extending from the vicinity of said in 40 a pair of shielding members closing the ends of
the cathode sleeve and of dimensions suiîicient
sulator toward the base of said one pole piece.
3. An electric discharge device comprising a
to shield said insulators Yto prevent the deposition
plurality of co-operating electrodes including 'a
of conductive material thereon incident to the
vaporization of electrons from the emissive sur
cylindrical cathode and an anode structure of
`
annular form having ltherein a central opening 45 faceof said cathode.
6. An electric discharge device comprising a
within which said cathode is positioned, a pair
of magnetic pole pieces spaced on opposite sides ’
plurality of enclosed co-operating electrodesV in
cluding a cathode and an anode structure sur
of said anode structure, said pole pieces each h'av
rounding said cathode, a pairof magnetic pole
ing therein a channel positioned; longitudinally
of the pole piece, a rigid cable construction lying 50 pieces spaced on opposite sides of said anode
within the channel of one of said pole’ pieces sup
structure', said pole pieces each having therein
a channel positioned longitudinally of the pole
porting said cathode, an insulator in said channel
piece, means positioning said cathode compris
near the end -thereof facing said anode structure
supporting and centering said cable, a second in
ing a'fconce'ntric cable construction attached to
sulator in the channel of the other pole piece and 55 said cathode and‘extending through the channel
of one of said pole pieces, an insulator support
including- a member centering said cathode, and
ing and centering said cable and' close-ly'v engaging
a pair of shielding members at the ends» of the
cylindrical-cathode to prevent the deposition of
the channel Wall of said pole piece, and a copper
conductiveY material on said insulators.
sleevein abutment with said insulator andl close
4. An electric discharge device comprising a 60 ly ñtted tothe channelwall and extending from
plurality of co-operating electrodes including a
said insulator to .the baseof- said one polev piece.
^ 7. An electric discharge device comprising a
cathode having a cylindrical sleeve provided with
plurality of co-operating'electrodes including a
an electron-v emissive surface and Y an annular
anode, structure havingy therein a centrallopening
cathodel and „an anode structure surrounding said
within which said sleeve is positioned'. a pair of 65 cathode, a pair of magnetic pole pieces'> spaced
magnetic pole’pieces spaced on opposite sides of
onopposite sides of said yanode structure'and each
said anode structure, said polepieces each-having
therein a channel vextending longitudinally- ofthe
pole piece, a rigid cable construction ¿lying within
having therein a channel of vcircular cross sec
tion positioned longitudinally of the pole piece',
anda concentric tubulan outer member, afrcath
ode- heating> element'substantially» surrounded byv
means positioning said cathode comprising a`
concentric cable- construction attached to said
cathode for supplying current-to» a cathode heat
ì ing element and extending throughV the channel
of one of- said pole pieces; an insulator centering
said sleeve- and having `one lterminal conductively`
and supporting said cable located Withinv the
' the channel of one or" said pole pieces supporting
said» cathode and’comprising an inner member
@soneries tof Said-„inner Conductor, „aniinsnlator 7:5 challlieiwithin.; the; vicinity cisaidA cathode ,- and
2,406,276
10
in close engagement with the channel wall, and
a, metallic tube in abutment with said insulator
and extending therefrom to the base of said one
pole piece.
~
8. An ultra high frequency electric discharge
device comprising a plurality of enclosed co
operating electrodes designed to have electrical
in alinement with each other, means supporting’
said cathode comprising a rigid concentric cable
construction including spaced inner and outer
conductors and extending through the channel
of one of said pole pieces, an insulator in close
engagement with the channel wall of said one
pole piece and extending beyond the pole face
and geometrical symmetry about a longitudinal
thereof in the direction of said cathode,V a cen
axis and 4comprising a cylindrical thermionic
tering insulator in the channel of the other pole
cathode and an annular anode structure provided 10 piece and supporting a metallic pin in electrical
with a circular central opening within which
contact with said cathode, and a pair of shield
said cathode is positioned, a pair of magnetic
ing discs positioned between said cathode and
pole pieces spaced on opposite sides of said anode
said pole faces to prevent the deposition of con
_structure and having pole faces of substantially
ductive material on said insulators incident to
circular cross section, said pole pieces each hav 15 the vaporization of electrons from the emissive
ing therein a channel of circular cross section
surface of said cathode.
positioned longitudinally of the pole pieces and
GEORGE M. WHITE.
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