7665A
Hydrogen-Filled Ceramic Thyratron
The data to be read in conjunction with the Hydrogen
Thyratron Preamble.
DESCRIPTION
The 7665A is a rugged hydrogen thyratron designed for use in
compact military and civil radars. It has a ceramic envelope with
a mounting flange and flying lead connections.
It features low jitter and low anode delay time and is suitable for
use at high pulse repetition rates; it can switch peak powers up
to 3 MW. The tube will operate over an ambient temperature
range of
755
to +130
8C.
A hydrogen reservoir is
incorporated.
This tube was designed to comply with, and is electrically
tested to, MIL-E-1/1485D.
Peak forward anode voltage . . . . . . 16
kV max
Peak inverse anode voltage . . . . . . 16
kV max
Peak anode current . . . . . . . . 350
A max
Average anode current . . . . . . . 500
mA max
Rate of rise of anode current . . . .
2000 A/ms max
Anode heating factor . . . . . . . 5 x 10
9
VApps max
GENERAL
Electrical
Cathode (connected internally
to one end of heater) . .
Heater voltage . . . . .
Heater current . . . . .
Reservoir voltage . . . .
Reservoir current . . . .
Tube heating time (minimum)
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. . oxide coated
.
6.3
+
7.5% V
.
4.5
A
.
6.3
+
7.5% V
.
2.0
A
.
3.0
min
Mechanical
Seated height . . . .
Clearance required below
mounting flange . . .
Overall diameter
(mounting flange) . .
Net weight . . . . .
Mounting position . . .
Base . . . . . . .
. . 63.5 mm (2.500 inches) max
. . . 25.4 mm (1.000 inch) min
.
57.15 mm (2.250 inches) max
. .
160 g (0.35 pound) approx
. . . . . . . . . . any
. . . . . . flange mounting
PULSE MODULATOR SERVICE
MAXIMUM AND MINIMUM RATINGS
(Absolute values)
Min
Max
Anode
Peak forward anode voltage
(see note 1) . . . . . . . .
Peak inverse anode voltage (see note 2)
Peak anode current . . . . . .
Average anode current . . . . .
Rate of rise of anode current
(see note 3) . . . . . . . .
Anode heating factor . . . . . .
.
.
.
.
–
–
–
–
16
16
350
500
kV
kV
A
mA
Cooling
. . . . . . . . . . . natural or forced-air
When operating at maximum anode dissipation, forced-air
cooling up to 0.14 m
3
/min (5 ft
3
/min) should be directed into
the anode cup.
. –
. –
2000
A/ms
9
5 x 10 VApps
e2v technologies (uk) limited, Waterhouse Lane, Chelmsford, Essex CM1 2QU, UK Telephone: +44 (0)1245 493493 Facsimile: +44 (0)1245 492492
e-mail: enquiries@e2v.com Internet: www.e2v.com
Holding Company: e2v technologies plc
e2v technologies inc. 4 Westchester Plaza, PO Box 1482, Elmsford, NY10523-1482 USA Telephone: (914) 592-6050 Facsimile: (914) 592-5148
e-mail: enquiries@e2vtechnologies-na.com
#
e2v technologies (uk) limited 2005
A1A-7665A Issue 5, November 2005
282G/2639
MAXIMUM AND MINIMUM RATINGS
(Continued)
Min
Max
Grid
Unloaded grid drive pulse voltage
(see note 4) . . . . . .
Grid pulse duration . . . .
Rate of rise of grid pulse
(see note 3) . . . . . .
Peak inverse grid voltage . .
Forward impedance of
grid drive circuit . . . . .
. . 200
. . . 2.0
. . 300
. . . –
. .
50
600
–
–
200
500
V
ms
V/ms
V
O
Heaters
Cathode heater voltage . . . . . .
Reservoir heater voltage . . . . . .
Tube heating time . . . . . . . .
6.3
+
7.5%
6.3
+
7.5%
3.0
–
V
V
min
Environmental
Environmental performance
. . . . . . . see note 5
Ambient temperature . . . . . .
755
+130
8C
Altitude . . . . . . . . . . . –
3
km
– 10 000
ft
4. Measured with respect to cathode potential.
5. The tube has been designed to withstand the following
tests:
(a)
Vibration
– Vibrated at 10 g in each of 3 planes through
the range 10 to 50 Hz and back again to 10 Hz in 10
minutes whilst looking for resonances in the range 0 to
2000 Hz.
(b)
Long Duration Shock
– Tested at 100 g for 11 ms with 3
blows in each plane.
(c)
High Temperature Test
– Tested at an ambient
temperature of 150
8C
under normal operating
conditions for 5 hours.
6. The typical figures are obtained on test using conditions of
minimum grid drive. Improved performance can be
expected by increasing the grid drive.
7. The time interval between a point on the leading edge of
the unloaded grid pulse at 25% of the pulse amplitude and
the point where anode conduction takes place.
8. Taken as the drift in delay time over an 8-minute run at full
ratings between the second and tenth minutes of operation.
9. The variation of firing time measured at 50% of current
pulse amplitude.
HEALTH AND SAFETY HAZARDS
e2v technologies hydrogen thyratrons are safe to handle and
operate, provided that the relevant precautions stated herein
are observed. e2v technologies does not accept responsibility
for damage or injury resulting from the use of electronic devices
it produces. Equipment manufacturers and users must ensure
that adequate precautions are taken. Appropriate warning
labels and notices must be provided on equipments
incorporating e2v technologies devices and in operating
manuals.
CHARACTERISTICS
Min Typical Max
Critical DC anode voltage for
conduction (see note 6) .
Anode delay time
(see notes 6 and 7) . . .
Anode delay time drift
(see notes 6 and 8) . . .
Time jitter (see notes 6 and 9)
Heater current (at 6.3 V)
.
Reservoir current (at 6.3 V) .
. . –
. . –
.
.
.
.
.
.
.
.
–
–
3.5
1.0
0.4
0.25
0.05
3.0
4.5
2.0
1.0
0.4
0.1
5.0
5.5
3.0
kV
ms
ms
ns
A
A
High Voltage
Equipment must be designed so that personnel cannot come
into contact with high voltage circuits. All high voltage circuits
and terminals must be enclosed and fail-safe interlock switches
must be fitted to disconnect the primary power supply and
discharge all high voltage capacitors and other stored charges
before allowing access. Interlock switches must not be
bypassed to allow operation with access doors open.
NOTES
1. This is the maximum forward hold-off voltage imposed on
the thyratron in a pulse modulator circuit. Tubes are tested
at 18 kV peak forward anode voltage with the charging
reactor inductance and pulse forming network capacitance
resonant at 1000 pps For instantaneous starting applications
the maximum permissible peak forward voltage is 16 kV;
this must not be reached in less than 0.04 s and there must
be no overshoot.
2. In pulsed operation the peak inverse anode voltage,
exclusive of a spike of 0.05
ms
maximum duration, must not
exceed 5.0 kV during the first 25
ms
after the pulse.
3. This rate of rise refers to that part of the leading edge of the
pulse between 25% and 75% of the pulse amplitude.
X-Ray Radiation
All high voltage devices produce X-rays during operation and
may require shielding. The X-ray radiation from hydrogen
thyratrons is usually reduced to a safe level by enclosing the
equipment or shielding the thyratron with at least 1.6 mm
(
1
/
16
inch) thick steel panels.
Users and equipment manufacturers must check the radiation
level under their maximum operating conditions.
7665A, page 2
#
e2v technologies
OUTLINE
(All dimensions without limits are nominal)
5027C
ANODE CONNECTION FITTED
WITH 8-32 UNC SCREW
Ref
A
B
C
D
E
F
G
H
J
K
L
M
Millimetres
61.90
+
1.52
34.93
+
0.25
49.20
+
1.52
7.09 max
0.81
25.4 max
38.1 max
4.19
51.6
57.15 max
152.4
5.16
Inches
2.437
+
0.060
1.375
+
0.010
1.937
+
0.060
0.279 max
0.032
1.000 max
1.500 max
0.165
2.031
2.250 max
6.000
0.203
1B
A
C
E
F
SEE NOTE 2
MOUNTING FLANGE
SEE NOTE 1
D
Inch dimensions have been derived from millimetres.
Outline Notes
SEE NOTE 3
1G
RESERVOIR HEATER LEAD (RED)
L LONG, TAG TO FIT
1M
TERMINAL
GRID LEAD (GREEN) L LONG
TAG TO FIT
1M
TERMINAL
1. The mounting flange is the connection for the
cathode, cathode heater return and reservoir
heater return.
2. A minimum clearance of 25.4 mm (1.000 inch)
must be allowed below the mounting flange.
3. Where e2v technologies gives prior agreement
to the use of alternative lead/mounting ar-
rangements on these posts, great care must be
taken to avoid damaging the threads and the
metal/ceramic joints. A flat wrench must be
used to hold the nut nearest the ceramic while
a torque wrench, set to a value of less than
0.046 kg-m (4 lb-in), is used on the other nut.
1K
CATHODE HEATER LEAD (YELLOW)
L LONG, TAG TO FIT
1M
TERMINAL
4 HOLES
1H
EQUISPACED
ON J PCD
Whilst e2v technologies has taken care to ensure the accuracy of the information contained herein it accepts no responsibility for the consequences of any use
thereof and also reserves the right to change the specification of goods without notice. e2v technologies accepts no liability beyond that set out in its standard
conditions of sale in respect of infringement of third party patents arising from the use of tubes or other devices in accordance with information contained herein.
#
e2v technologies
Printed in England
7665A, page 3
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