HAMAMATSU R2949 Datasheet

Modified R928, 8 × 6mm Photocathode Area Size

Low Dark Counts, Extended Red Multialkali, High Sensitivity

For Photon Counting Applications

FEATURES

Low Dark Counts ................................................. 300cps (at 25°C)

Low Dark Current ............................................. 2nA (after 30min.)

Wide Spectral Response ........................................ 185 to 900 nm

High Cathode Sensitivity

Luminous ...................................................................... 200µA/lm

Radiant at 400nm ........................................................... 68mA/W

High Anode Sensitivity (at 1000V)

Luminous ...................................................................... 2000A/lm

Radiant at 400nm .................................................... 6.8 × 10

Low Drift and Hysteresis

PHOTOMULTIPLIER TUBE

R2949

(Low Dark Counts Type of R928)

5

A/W

The R2949 is a 28mm (1-1/8 inch) diameter, 9-stage, side-on type pho­tomultiplier tube having the same extended red multialkali photo­cathode as the R928. The R2949 features very low dark counts,
extremely high quantum efficiency, high gain, good S/N ratio and wide
spectral response from UV to near infrared.
The R2949 is well suited for use in various low-level photometries such
as general single photon counting applications and fluorescence life
time measurement.
The R2949 is directly interchangeable with the R928.

GENERAL

Parameter

Spectral Response
Wavelength of Maximum Response

Photocathode
Window Material

Dynode

Direct
Interelectrode
Capacitances

Base
Weight

Suitable Socket (Option)
Suitable Socket Assembly (Option)

Material
Minimum Useful Size

Secondary Emitting Surface
Structure
Number of Stages
Anode to Last Dynode
Anode to All Other Electrodes

Description/Value

185 to 900

400

Multialkali

8 × 6

UV glass

Multialkali

Circular-cage

9
Approx. 4
Approx. 6

11-pin base

JEDEC No. B11-88

Approx. 45
E678-11A

E717-21

Unit

nm
nm

—

mm

—
—
—

—
pF
pF

—

g
—
—

Figure 1: Typical Spectral Response

TPMSB0155EA

100

10

QUANTUM
EFFICIENCY

1

QUANTUM EFFICIENCY (%)

0.1

CATHODE RADIANT SENSITIVITY (mA/W)

0.01
200 400 600 800 1000

CATHODE
RADIANT
SENSITIVITY

WAVELENGTH (nm)

Subject to local technical requirements and regulat ions, availability of products included in this promotional material may var y. P lease consult with our sales office.
Information furnished by HAMA M ATSU is believed to be reliable. However, n o responsibility is assumed for possible inaccuracies or omissions. Specifications are

subject to change without notice. No patent rights are granted to any of the circuits described herein.

1998 Hamamatsu Photonics K.K.

©

PHOTOMULTIPLIER TUBE R2949

MAXIMUM RATINGS (Absolute Maximum Values at 25 °C)

Parameter Value Unit

Supply Voltage

Between Anode and Cathode

Between Anode and Last Dynode
Average Anode Current
Ambient Temperature

1250

250

A

0.1

-80 to +50

Vdc
Vdc

mA

°C

CHARACTERISTICS (at 25°C)

Parameter Min. Unit

Quantum
Efficiency
Luminous

at 255nm

B

at 194nm
Cathode
Sensitivity

Radiant

at 254nm

at 400nm

at 633nm

at 852nm

Red/White Ratio
with R-68 Filter

D

Blue
Luminous

E

at 194nm
Anode
Sensitivity

Radiant

at 254nm

at 400nm

at 633nm

at 852nm

E

Gain
Anode Dark Counts

F

at +25°C

at -20°C
Anode Dark Current

F

ENI (Equivalent Noise Input)
Time

Response
Anode Current

Stability

K

Anode Pulse
Rise Time

E

Electron Transit Time
Current Hysteresis
Voltage Hysteresis

H

Typ.

—

140

—
—
—
—
—

C

0.1
—

1000

—
—
—
—
—
—
—
—
—

G

—
—

J

—
—
—

25.3
200

18
52
68
41

3.5

0.3

7.5

2000

1.8 × 10

5.2 × 10

6.8 × 10

4.1 × 10

3.5 × 10

1.0 × 10
300

3
2

1.2 × 10

2.2
22

0.1

1.0

-16

Max.

—
—

—
—
—
—
—

—
—

—

5

—

5

—

5

—

5

—

4

—

7

—

500

—
25
—

—
—

—
—

%

µA/lm
mA/W
mA/W
mA/W
mA/W
mA/W

—

µA/lm-b

A/lm
A/W
A/W
A/W
A/W
A/W

—
cps
cps

nA

W

ns

ns

%

%

NOTES

A: Averaged over any interval of 30 seconds maximum.
B: The light source is a tungsten filament lamp operated at

a distribution temperature of 2856K. Supply voltage is
100 volts between the cathode and all other electrodes
connected together as anode.

C: Red/white ratio is the quotient of the cathode current

measured using a red filter interposed between the light
source and the tube by the cathode current measured
with the filter removed under the same conditions as
Note B.

D: The value is cathode output current when a blue filter

(Corning CS 5-58 polished to 1/2 stock thickness) is
interposed between the light source and the tube under
the same conditions as Note B.

E: Measured with the same light source as Note B and with

the anode-to-cathode supply voltage and voltage
distribution ratio shown in Table 1.

F: Measured with the same supply voltage and the voltage

distribution ratio as Note E after 30 minute storage in
the darkness.

G: ENI is an indication of the photon limited signal-to-noise

ratio. It refers to the amount of light in watts to produce
a signal-to-noise ratio of unity in the output of a
photomultiplier tube.

2q•ldb•G•∆f

ENI =

where q = Electronic charge (1.60 × 10
ldb = Anode dark current (after 30 minute storage)
in darkness) in amperes
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.

H: 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.

J: 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 measurement, the
whole photocathode is illuminated.

K. Hysteresis is temporary instability in anode current after

light and voltage are applied.

ANODE

CURRENT

Hysteresis = × 100 (%)

S

I

I

i

0567 (MINUTES)

I

- I

max.

min.

I

j

I

min.

max.

-19

coulomb)

TIME

Table 1: Voltage Distribution Ratio

Electrodes
Distribution
Ratio

Supply Voltage= 1000Vdc
K: Cathode, Dy: Dynode, P: Anode

K Dy11Dy21Dy31Dy41Dy51Dy61Dy71Dy81Dy9

P

11

(1) Current Hysteresis
The tube is operated at 750 volts with an anode current of 1
microampere for 5 minutes. The light is then removed from
the tube for a minute. The tube is then re-illuminated at 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 microampere 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 supply voltage is reduced to
the previous value and the tube is re-illuminated for a
minute to measure the variation.