Metal package PMT with Cooler
Photon Counting Head H7421 Series
The H7421 series are photon counting head devices containing a metal
package photomultiplier tube having a GaAsP/GaAs photocathode and a
thermoelectric cooler. The thermoelectric cooler reduces thermal noise gen-
erated from the photocathode which also offers a high quantum efficiency, al-
lowing measurement to be made with a good S/N ratio even at very low light
levels.
The H7421-40 has high sensitivity on wavelength from 300 nm to 720 nm.
The H7421-50 is sensitive over a wide spectral range from 380 nm to 890 nm.
The photomultiplier tube is maintained at a constant temperature by monitor-
ing the output from a thermistor installed near the photomultiplier tube and
regulating the current to the thermoelectric cooler.
Heatsink with fan (A7423) sold separately
Product Variations
Type No.
H7421-40
H7421-50
Spectral Response
300 nm to 720 nm
380 nm to 890 nm
Features
GaAsP photocathode, QE 40 % at peak wavelength
GaAs photocathode, QE 12 % at peak wavelength
Specifications
Parameter
Input Voltage
Max. Input Voltage for Main Unit
Max. Input Current for Main Unit
Max. Input Voltage for Thermoelectric Cooler
Max. Input Current for Thermoelectric Cooler
Effective Area
Peak Sensitivity Wavelength
Count Sensitivity
Count Linearity *
1
Typ.
Dark Count *
2
*
3
Max.
Pulse-pair Resolution
Output Pulse Width
Typ.
Output Pulse Height *
4
Min.
Recommended Load Resistance
Signal Output Logic
Operating Ambient Temperature
Storage Temperature
Weight
H7421-40
+4.5 to +5.5
+6
50
2.6
2.2
5
580
7.8
脳
10
5
1.5
脳
10
6
100
300
70
30
3.6
3.0
50
Positive logic
+5 to +35
-20 to +50
340
H7421-50
800
3.9
脳
10
5
1.5
脳
10
6
125
375
Unit
V
V
mA
V
A
mm
nm
-1
路pW
-1
s
s
-1
s
-1
ns
ns
V
鈩?/div>
鈥?/div>
擄C
擄C
g
*1: Random pulse, at 10 % count loss
*2: PMT setting temperature 0
擄C,
used with C8137, M9011 and A7432
*3: After 30 minute storage in darkness
*4: With input voltage +5 V, Load resistance 50
鈩?/div>
and Coaxial cable RG-174/U (450 mm)
Cooling Specifications
Parameter
Cooling Method
Max. Cooling Temperature (鈭員) *
5
Cooling Time *
5
*5: Input current to thermoelectric cooler = 2.0 A
H7421-40/H7421-50
Thermoelectric cooling
35
Approx. 5
Unit
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