6.5 OTHER MALFUNCTIONS
NO.
SYMP TOM
PROB A BLE CAUSE
COR REC TION
1
Cooling wa ter is boil ing, as in di cated by a
me dium-frequency whine com ing from the
cham ber.
(a) Al loying of melted ma te rial is caus ing a
ther mal short be cause sta tion ary beam is
at edge of pocket.
(a) Ap ply beam sweep, if pos si ble, or ad -
just de flec tion cur rent(s) so that the beam
is cen tered in the pocket.
(b) In ad e quate cool ing of ex posed pocket.
(b) Make sure that cool ing wa ter is chilled
to max. 20 C and that its flow rate is at or
above the min i mum value spec i fied in
sec tion 1.4.
(c) Weak per ma nent mag net.
(c) Check beam-spot po si tion with 0 A lon -
gi tu di nal de flec tion cur rent ap plied. If spot
is too far to ward rear of source (see Fig -
ure 6-1), have the per ma nent mag net
regaussed or re place it.
2
Rapid loss in field strength of per ma nent
mag net.
(a) Gun is be ing af fected by fields from
leads con nected to some other ac de vice
in side the cham ber.
(a) Re route the leads of the other ac de -
vice as far away from the gun’s per ma nent
mag net as pos si ble. Then check
beam-spot po si tion with 0 A lon gi tu di nal
de flec tion cur rent ap plied. If spot is too far
to ward rear of pocket (see Fig ure 6-1), re -
place per ma nent mag net or have it
regaussed.
(b) Mag net has been dropped or struck
against a hard sur face.
(b) Check beam-spot po si tion with 0 A lon -
gi tu di nal de flec tion cur rent ap plied. If spot
is too far to ward rear of source (see Fig -
ure 6-1), re place per ma nent mag net or
have it regaussed.
(c) Gun has been heated above its max i -
mum bakeout tem per a ture of 150° C.
(c) Same as (b).
3
An ode is burned through.
(a) An ode has be come di rectly ex posed to
the elec tron beam.
(a) In stall new an ode, mak ing sure that
beam for mer com pletely shields an ode
from fil a ment. For in struc tions on cor rectly
align ing the high-per for mance emit ter, see
sec tion 4.4.
4
Ion gauge in di cates a pres sure burst when
cru ci ble is ro tat ing.
(a) Wa ter is leak ing past the gun’s quad
ring.
(a) Re place quad ring. Re mem ber to lu bri -
cate the new quad ring prop erly with
Apiezon L or an equiv a lent prod uct.
5
Cru ci ble sticks or is dif fi cult to ro tate.
(a) Quad ring is in ad e quately lu bri cated.
(a) Re place quad ring. Re mem ber to lu bri -
cate the new quad ring prop erly with
Apiezon L or an equiv a lent prod uct.
(b) Worn bear ings in bear ing hous ing as -
sem bly or drive shaft as sem bly.
(b) Check bear ings and re place as nec es -
sary.
Troubleshooting
6-8
0101-9004-0A
STIH-270-2PT
