M A I N F E A T U R E S
Compact Size
The CPM is one of the smallest head-
on type detectors, with a 10.5 mm
diameter including encapsulation. The
photocathode has a useful diameter
of more than 5 mm. The tube is smal-
ler, easier to use, and more rugged
than discrete dynode types. Only a
single high voltage supply of up to
3000 volts is necessary; no external
voltage divider network is required.
A variety of different sizes will be avai-
1
3
Unpotted / inch Channel Photomultiplier
1
3
2
4
lable soon ( / ” and / ”).
Fig. 1: Typical current amplification
1 E+09
1 E+08
1 E+07
1 E+06
1 E+05
1 E+04
1 E+03
1 E+02
Ultra high anode sensitivity
At the maximum bias voltage of 3000 V,
8
gains can exceed 10 . At 2400 V, an-
6
ode sensitivity is typically 3 x 10 A/W
at a wavelength of 410 nm with a bi-
alkali photocathode. This performan-
ce surpasses conventional PMTs by
one to two orders of magnitude and
beats APDs by approximately five or-
ders of magnitude (Fig. 1).
1000
1500
2000
2500
3000
Bias Voltage (V)
Extremely low dark current
Fig. 2: Typical anode dark current
The electron multiplication in the
channel is virtually silent, so dark cur-
rent depends only on the photoca-
thode material, leakage currents are
negligible. Bialkali photocathodes ex-
hibit typical dark count rates of 10
1 E-05
1 E-06
1 E-07
1 E-08
1 E-09
1 E-10
1 E-11
1 E-12
8
cps at a gain of 3 x 10 , while UV ca-
thodes have dark count rates below 1
cps. In analog DC mode, the typical
dark noise for a bialkali photocathode
7
is 20 pA at a gain of 10 . In general,
C 942
C 972
C 962
C 952
the noise level of the PerkinElmer
Optoelectronics CPM is one to two
orders of magnitude lower than dyn-
ode PMTs, resulting in a significant-
ly higher dynamic range (Fig.2).
C 922
C 911
1000
1500
2000
Bias Voltage (V)
2500
3000
PERKINELMER [ PERKINELMER OPTOELECTRONICS ]
