R7639 Datasheet, PDF (2/4 Pages) Hamamatsu Corporation – PHOTOMULTIPLIER TUBE

PHOTOMULTIPLIER TUBE R7639
MAXIMUM RATINGS (Absolute Maximum Values)
Parameter
Supply Voltage
Rating
Unit
Between Anode and Cathode
1250
V dc
Between Anode and Last Dynode
250
V dc
Between Successive Dynodes
Between First Dynode and Cathode
Average Anode Current
Ambient Temperature
250
250
0.1
-30 to +50
V dc
V dc
mA
°C
CHARACTERISTICS (at 25°C)
Parameter
Cathode sensitivity
Quantum Efficiency at 121.6 nm
at 155 nm
Radiant at 121.6 nm
at 155 nm
Anode Sensitivity
Radiant at 155 nm
Gain
Anode Dark Current (After 30 minutes storage in the darkness)
ENI (Equivalent Noise Input)
Time Response
Anode Pulse Rise Time
Electron Transit Time
Transit Time Spread (TTS)
Anode Current Stability
Light Hysteresis
Voltage Hysteresis
Min. Typ.
Max.
10
26
—
—
40
—
10
26
—
—
50
—
1.0 × 10⁴ 1.5 × 10⁵ —
— 3.0 × 10⁶ —
—
0.5
5
— _{1.46 × 10}-16 —
—
2.2
—
—
22
—
—
1.2
—
—
0.1
—
—
1.0
—
Unit
%
%
mA/W
mA/W
A/W
—
nA
W
ns
ns
ns
%
%
NOTES
: Averaged over any interval of 30 seconds maximum.
: Measured with the same light source as Note B and with the voltage
distribution ratio shown in Table 1 below.
Table 1: Voltage Distribution Ratio
Electrode K Dy1 Dy2 Dy3 Dy4 Dy5 Dy6 Dy7 Dy8 Dy9 P
Distribution
Ratio
1111111111
Supply Voltage=1000 V dc
K: Cathode Dy: Dynode P: Anode
: Measured with the same supply voltage and voltage distribution ratio
as Note E after removal of light.
: ENI is an indication of the photon-limited signal-to-noise ratio. It re-
fers to the amount of light in watts to produce a signal-to-noise ratio
of unity in the output of a photomultiplier tube.
ENI = ^{2q·ldb·G·∆f}
S
where q = Electronic charge (1.60 × 10^-19 coulomb).
ldb = Anode dark current(after 30 minutes storage) in am-
peres.
G = Gain.
∆f = Bandwidth of the system in hertz. 1 hertz is used.
S = Anode radiant sensitivity in amperes per watt at the
wavelength of peak response.
: The rise time is the time for the output pulse to rise from 10 % to 90 %
of the peak amplitude when the entire photocathode is illuminated by
a delta function light pulse.
: The electron transit time is the interval between the arrival of delta
function light pulse at the entrance window of the tube and the time
when the anode output reaches the peak amplitude. In measure-
ment, the whole photocathode is illuminated.
: Also called transit time jitter. This is the fluctuation in electron transit
time between individual pulses in the signal photoelectron mode, and
may be defined as the FWHM of the frequency distribution of elec-
tron transit times.
: Hysteresis is temporary instability in anode current after light and
voltage are applied.
li
l _max.
l _min.
0
5
6
7 (minutes)
Hysteresis =
l _{max —} l _min.
li
× 100 (%)
TIME
TPMSB0002EA
(1) Light Hysteresis
The tube is operated at 750 volts with an anode current of 1 micro-am-
pere for 5 minutes. The light is then removed from the tube for a minute.
The tube is then re-illuminated by the previous light level for a minute to
measure the variation.
(2) Voltage Hysteresis
The tube is operated at 300 volts with an anode current of 0.1 micro-
ampere for 5 minutes. The light is then removed from the tube and the
supply voltage is quickly increased to 800 volts. After a minute, the sup-
ply voltage is then reduced to the previous value and the tube is re-
illuminated for a minute to measure the variation.