.
.
.
.
1
| OF T
ORNL P
2640
•
the
"
.
.
1
i
man har
a
#
:
.
-
.
-
,'
.
.
'.
.
.
-
:
:.
.
21:131333
11
.
11:25 114 115
1
.
MICROCOPY RESOLUTION TEST CHART
NATIONAL BUREAU OF STANDARDS - 1963
ORNnf 2640
.....anan
...................
Conf-661016-23.
H.C. $ 7:00. 2008:50
RELEASED FOR ANNOUNCEMENT
NOV 29 1966

** TRON-CORE MINIMUM "B" MAGNET*
W. Helchin and I. Alexeff
MACIE
IN NUCLEAR SCIENCE ABSTRACTS
Oak Ridge National Laboratory
Oak Ridge, Tennessee
...................
vor................ noen weer....
The iron-core minimum B magnet that I will discuss is much larger
but similar to the one described by I. Alexeff in the October, 1965 ORNL
Thermonuclear Division Semiannual Progress Report. In these minimum B
magnets the field is spherical, and it has a "magnetic well" in which the
absolute value of the magnetic field increases in every direction from
the non-zero center. The ircn core is used to concentrate and direct the
magnetic field into the desired spherical configuration.
Fig. I shows the general arrangement used for this larger iron-core:
inagnet. The magnetomotive force is external to the iron core. An existing
isotope separation tank, Fig. 2, provided ideal facilities for the iron
.core magnet. The magnetomotive force is provided by large coils on either
side of the tank. This facility also has a complete vacuum system. The
port openings to the diffusion pumps are at the rear of the tank. The front
of the tank has a flange where the cover plate can be mounted and realed.
To shape and concentrate the field this iron-core magnet has two symetric
po.le pieces bolted together with non-magnetic braces. Thė field is directed
toward the center by the triangular shape of the pole pieces. Fourteen 1/2-
inch thick Arnco iron plates were used to form each pole piece. The base of
each pole piece is 40 inches by 7 inches thick, except in the center region
where they were 3 inches thick.
In this next view, Fig. 3, is tij cavity for the minimum B region. This
center spherical cavity is 10 inches in diameter. The 1/2-inch thick plates
were staggered so as to conform to the desired spherical shape.
*Research sponsored by the U. S. Atomic Energy Commission under contract with
the Union Carbide Corporation.
H
d
po
...
T
:""
"
!
9.7
"
!..
.
.
:
:
:
...
D
:.
'..
717
.
A
....
4
..
TT
..
-
....
M
..
.
.
...
....
.....
.
.
---
ren o
..
----
.....
-
F OT
To measure the field intensity, an aluminum plate, Fig. 4, with hoies
spaced one-hall inch on centers in the X and Y directions was used. For
the z direction varying lengths of rods were used. By the use of this
plate, the rods and magnetic probe, the field in one quandrant of the sphere
could be measured. An axial Hall probe was used to measure the field at
each point. This probe was held by hand at the tip of the pins and for each
· reading the probe was oriented to determine maximum value. . .
Typical data are shown in Table 5. These data were taken at the central
horizontal plane, 1/2 and 1-1/2 in. above the central plane. With the center
set åt 3 kilogauss, this shows an axial mirror ratio of 1.5 to 1 and a radial
ratio of 1.2 to 1. The next data, Table 6, were taken in the horizontal plane
2-1/2, 3-1/2, and 4-1/2 inches above center. At full power of the facility
the center of the magnet was at 6.25 kilogauss with an axial mirror ratio
of 1.3 to 1 and a negative radial ratio. Obviously, the mirror ratios fell
short of the original hopes of having a minimum ratio of at least 1.5 to 1.
in any direction away from the center. Further, it was evidenced that the
field values next to the midsection of each pole piece was lower than in
other regions. At this point it was decided to disassemble and reassemble the
pole piece laminations so that the inner surface would diverge from the
spherical center cavity. This change resulted in an axial ratio of 1.4 to 1
and a radial ratio of 1.8 to 1 when the center was set at 3 kilogauss. . .
These ratios were still too low and unbalanced, so it was decided to
add a maximum amount of iron laminations to the pole pieces. The pole pieces,
Fig. 7, after modification were in the form of pyramids with base dimensions
23 inches hy 48 inches. This change increased the base area of each pole
piece by a factor of more than 4. The weight of the assembled magnet, Fig. 8,
was 5500 pounds. Fig. 9 shows this iron-core magnet installed in the isotope
separation facility.
With the center set at 3 kilogauss, the axial ratio was 1.6 to 1 and
the radial ratio 2 to 1. At full power of the facility, there was 9 kilo-
gauss in the center with an axial ratio of 1.2 to l and a radial. ratio of
1.1 to 1.
Some shiming was tried by placing 1-1/8" x 1" crescents in the throat
of each pole piece. At full power there was 10.7 kilogauss at the center,
17.2 kilogauss at the throat, 14.5 kilogauss at the side, and between poles
11.4 kiloguuss. This gives a minimum mirror ratio of about 1.06 to 1.
Since the region between pole pieces was low, a 1/2 inch diameter steel rod
was formed and placed in this mid-region as shown in Fig. 10. This gave a
minimum mirror ratio of about 1.3 to 1. From these results it appears that
at these higher fields further shimming and pole piece shaping will be
necessary to get a closed sphere with a minimum mirror ratio of 1.5 to 1.
Along with the continued improvement of this iron-core magnet, future plans,
are to start some plasma experiments with this minimum B magnet.
Also, for the future, plans have been completed to assemble another
iron-core magnet with an oblong cavity 16 inches by 10 inches with the 16
inches along the axis of the magnet. This oblong configuration was chosen
to obtain a minimum B field with higher mirror ratios. This minimum B magnet
also is to be used for further plasma experiments.
LEGAL NOTICE
This report was prepared as an account of Government sponsored work, Nelther the United
States, nor the Commission, nor any person acting on behalf of the Commission:
A. Makes any warranty or representation, expressed or implied, with respect to the accu-
ricy, completenego, or usefulness of the information contained in this report, or that the use
of any information, apparatus, method, or process disclosed in this report may not infringe
privately owned righto; or
use of any information, apparatus, method, or process disclosed in this report,
As used in the above, "person acting on behalf of the Commission" includes any em-
ployee or contractor of the Commission, or employeo of such contractor, to the extent that
such employce or contractor of the Commission, or employee of such contractor prepares,
disseminates, or provides access to any ina vrmation pursuant to his employment or contract
with the Commission, or als employment with such contractor.
: "
:
. "
" -- --
-- -- --
-- trụH TẾ - Trang
FIGURES
Fig. 1 - ORNL Dwg. 66-6617
Fig. 2 - ORNL Photo 73288
Fig. 3 - ORNL Photo 73289
Fig. 4 - ORNL Photo 84991
Table 5 - Tables 8.2, 8.3, 8.4, ORNL - 3989 Thermonuclear Div. Seniann.
Prog. Rept., April 30, 1966.
Table 6 - Tables 8.5, 8.6, 8.7, ORNL-3989 Thermonuclear Div. Semiann.
Prog. Rept., April 30, 1966.
Fig. 7 - ORNL Photo 84995
Fig. 8 - ORNL Photo 84993
Fig. 9 - ORNL Photo 84992
Fig.10 - ORNL Photo 84994
..
.
..
.
.
#2
....!
:::
#
1
ORAL- DWG 65-EC17
"...Hmmetr..
PROTON

MINHAUM-
A.AGNET
.
.
.
.
NiAGNET
AXIS

..
•
1
RON
CORE
BETA TANK
IL
DONDUPUUUUU
Fig. 8.9. Arrongemunt of Minimum.3 Mognct in Beta
Tonk rocility
rominenciasniemowland e ondoriais normalcom
Fig. 8.10. Mininiurr-B Magnet in Beto Tank.
...............
...
..
.
..
...
.
-... :
-
.
.......... *::.....
........................


1P 10 MET
....
.
5:
nning
DO
',
.
..
sediminowaniem
d
o
some
inside towanithandicciario.
.
·
Fig. 8.11. Alinimum-8 Magnet. The center spherical opening is 10 in. in diameter.
.
1.
و
۰۰۰ي ، ه و
ی ... ايه . لا
،
ايه 1،
1-
مے
1
.
2
، اپي، .
- . ه .
.
..
....:::
.. ..
. . . . ..
.
.
.
.
:::
...
.. ...
.............
. ... ..
. .
.. ..
.
..
...
.
النمنم نمیشمدلماضشانسش
ندمنننبممننلنلننننه شد
.

مجب
• .. ما هو
'
. . .
.
مهند
منم مسنن منمنننمعنسیمسن
.., .
Toble 8.2. Field Measurements (kg) Token at the Central Horizontal Plane
Radial
(in.)
Axial (in.)
ļa ay hin 33
-
0
3
3.15
·
3.3
4.35
4.6
4.75
4.35
4.3
4.6
·
4.75
4.75
4.35
4.25
4.65
3.15
3.15
3.25
3.25
3.55
i
..?
. 2
.22
4.5
3.35
: 3.3
3.35
3.55
3.8
2.85
3.15
3.15
3.45
3.55
4.7
4.35
4.35
.4.55
...
3
3.05
3
3.2
3.35
3.45
3.65
3.65
3.65
3.2
3.7
3.7
3.65
4.0
4.65
3.95
4.0
4.0
· 3.8
4.35
4.5
4.4
4.15
4.8
4.4
3.8
:
4.5
4.55 ..
3.6
..
4.2
4.1
4.
3.6
3.65
3.0
3.6
3.95
3.9
3.35
3,15
......
.
****. ;.
:.:.:.:)
..
:::::............
.
.....................
.
.....-.-.:.:.
Toble 8.3. Field Measurements (kG) Token of the Horizontal Plane , in. Aborc Center
4.75
3.1
3.45
3.05
3.2
Radial
. Axial (in.)
(in.) Oil Taha 23. 3 A 4
3.05 3.15 3.35 3.6 3.95 4.35 4.7 4.95
4.6
3.05 3.2 3.4 *3.65
3.95
4.4 4.7.
4.55
3.1 3.2
3.75 . 4.0 C 4.4 . 4.75 4.8. 4.4
. 3.85 4.75 -4.5 4.
8 0 4.85
3 .4 3.45 3.5 3.7 4.0 : 4.35 4.7 5.0
2 3.3 3.45 3.55 3.8 4.15 .4.4 4.9 5.15
3.2 3.45 3.25 3.5 3.95 .4.5 . 4.85 5.15
3 3.4 3.35 3.5 3.65 4.35 4.6 4.95
4 3.6 3.55 3.65 3.95 4.20 4.55
3.2
3.5
3.55
1.3.4
2
4.85
.
4.4
5.0
.
.
.
3.1
Above Center
Toble 8.4. Fic!d Measurements (kg) Tuken of the Horizontal P
Radial
(in.)
3
4
Axial (in.)
2 2
3.45
3
5.2
-
.
2.7
3.35
3.35
6.35
8.69
4.9
AL
4.4
5.35
6.8
.
3.95
..
.
-
..
.
.
..
..
M
I
...
R
L
SL. -
'UTILI I
#16
- Poble 8.5
Table 8.5. Field Measurements (kG) Token at the Horizontol Pluno 2 in. Above Center
,
Axial (in.)
Radini
(in.)
.
i
sl
.a.
2
.3
3ina
3.6
4.1
:
:
4.8
6.15
4.25
5.15
6.25
· 6.85
4.5 :.
6.8
.
6.5
6.8
5.2
.
:
6,75
6.8
6.4
4.
a la
6.65
s.0
.
8.15
7.6
.
-
--•.
.
..!!
......................................
...................
..
olonc 3% in. '
----.
:. :. :..: .:.: .:. .. ...
... Toble 8.6. Field Meosurements (kG) Taken of the florizontal Plane 3 in. Above Center
Axial (in.)
Radial
(in.)
i
sig
:
?... 2
s
3
a
ta
-
-
3
8.75
-
3.75
8.25
3.9
...
4.4..
8.2
.;
6.9
9.2
4.75
9.9
2.45
7.45
.
3.85
.
.6.4
6.75 .
6.2
6.0
6.15
4
..
Axial (in.)
Axi
Radial
(in.) ŪĶīse a alla
1
10 ..7.75
10
11 :
..
.
2.8
7.75
8.85
7.7
3.15
.
9.3
8.8
8.2
5.45
6.3
6.4
5.1
محمد مستمعه

اداره
T
...
مت
.
::

..ضم منسسنية
-
::ة
...•::
.
.

. . .
.. ..
.. ... .....
.
.. ..
..
....
I
بسمة
. .
.
.
امام
..............
.... ............

...
.
"
سه عدد منهم

یا

بنیامد. مة
|
|
لا
.
ا
::
.
نویسنده: دا .. ب
ا
:
-
تيم
:- ......
1
:
ه .
... ... ..
.
.
.
2
-
!.
...
.
FT
C
END

1
-
:
:
.
I
..
.
.
2.
•
.
:
DATE FILMED
12/ 21 / 66




-
I
4
...
.
ARMA
.
.
2.1 VW