FLAME SENSOR
UV TRON
R2868
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Information furnished by HAMAMATSU is believed to be reliable. However, no responsibility is assumed for possible inaccuracies or omissions.
Specifications are subjected to change without notice. No patent rights are granted to any of the circuits described herein. 1997 Hamamatsu Photonics K. K.
Quick Detection of Flame from Distance,
Compact UV Sensor with High Sensitivity and Wide Directivity,
Suitable for Flame Detectors and Fire Alarms.
Hamamatsu R2868 is a UV TRON ultraviolet detector that makes
use of the photoelectric effect of metal and the gas multiplication
effect. It has a narrow spectral sensitivity of 185 to 260 nm, being
completely insensitive to visible light. Unlike semiconductor
detectors, it does not require optical visible-cut filters, thus
making it easy to use.
In spite of its small size, the R2868 has wide angular sensitivity
(directivity) and can reliably and quickly detect weak ultraviolet
radiations emitted from flame due to use of the metal plate
cathode (eg. it can detect the flame of a cigarette lighter at a
distance of more than 5 m.).
The R2868 is well suited for use in flame detectors and fire
alarms, and also in detection of invisible discharge phenomena
such as corona discharge of high-voltage transmission lines.
APPLICATIONS
q
Flame detectors for gas/oil lighters and matches
q
Fire alarms
q
Combustion monitors for burners
q
Inspection of ultraviolet leakage
q
Detection of discharge
q
Ultraviolet switching
GENERAL
Parameters
Rating
Units
Spectral Response
185 to 260
nm
Window Material
UV glass
--
Weight
Approx. 1.5
g
Dimensional Outline
See Fig. 3
--
MAXIMUM RATINGS
Parameters
Rating
Units
Supply Voltage
400
Vdc
Peak Current
1)
30
mA
Average Discharge Current
2)
1
mA
Operating Temperature
-20 to +60
C
CHARACTERISTICS (at 25
C)
Parameters
Rating
Units
Discharge Starting Voltage (with UV radiation)
280
Vdc Max.
Recommended Operating Voltage
325
25
Vdc
Recommended Average Discharge Current
100
A
Background
3)
10
cpm Max
Sensitivity
4)
5000
cpm Typ.
NOTES:
1) This is the maximum momentary current that can be handled if its full width
at half maximum is less than 10
s.
2) If the tube is operated near this or higher, the service life is noticeably reduced.
Use the tube within the recommended current values.
3) Measured under room illuminations (approximately 500 lux) and recommended
operating conditions. Note that these values may increase if the following
environmental factors are present.
1. Mercury lamps, sterilization lamps, or halogen lamps are located nearby.
2. Direct or reflected sunlight is incident on the tube.
3. Electrical sparks such as welding sparks are present.
4. Radiation sources are present.
5. High electric field (including static field) generates across the tube.
4) These are representative values for a wavelength of 200 nm and a light input
of 10 pW/cm
2
. In actual use, the sensitivity will vary with the wavelength of the
ultraviolet radiation and the drive circuitry employed.
Figure 1: UV TRON's Spectral Response and Various
Light Sources
TPT B0009EA
200
300
400
500
600
700
800
900
100
WAVELENGTH (nm)
RELATIVE SENSITIVITY, RELATIVE INTENSITY
(ARBITRARY UNIT)
100
50
0
UV TRON s
SPECTRAL
RESPONSE
SUNLIGHT
GAS
FLAME
TUNGSTEN
LIGHT
ULTRAVIOLET
VISIBLE
INFRARED
FLAME SENSOR
UV TRON
R2868
1000pF
+
-
325
25Vdc
220pF
500V
10M
4.7 k
*
ANODE
UV TRON R2868
CATHODE
PULSE OUTPUT
10k
i
Figure 2: Angular Sensitivity (Directivity)
HAMAMATSU PHOTONICS K.K., Electron Tube Center
314-5, Shimokanzo, Toyooka-village, Iwata-gun, Shizuoka-ken, 438-0193, Japan, Telephone: (81)539/62-5248, Fax: (81)539/62-2205,
U.S.A.: Hamamatsu Corporation: 360 Foothill Road, Bridgewater, N.J. 08807-0910, U.S.A., Telephone: (1)908-231-0960, Fax: (1)908-231-1218
Germany: Hamamatsu Photonics Deutschland GmbH: Arzbergerstr. 10, D-82211 Herrsching am Ammersee, Germany, Telephone: (49)8152-375-0, Fax: (49)8152-2658
France: Hamamatsu Photonics France S.A.R.L.: 8, Rue du Saule Trapu, Parc du Moulin de Massy, 91882 Massy Cedex, France, Telephone: (33)1 69 53 71 00, Fax: (33)1 69 53 71 10
United Kingdom: Hamamatsu Photonics UK Limited: Lough Point, 2 Gladbeck Way, Windmill Hill, Enfield, Middlesex EN2 7JA, United Kingdom, Telephone: (44)181-367-3560, Fax: (44)181-367-6384
North Europe: Hamamatsu Photonics Norden AB: Frgatan 7, S-164-40 Kista, Sweden, Telephone: (46)8-703-29-50, Fax: (46)8-750-58-95
Italy: Hamamatsu Photonics Italia S.R.L.: Via Della Moia, 1/E, 20020 Arese, (Milano), Italy, Telephone: (39)2-935 81 733, Fax: (39)2-935 81 741
Figure 3: Dimensional Outline (Unit: mm)
Figure 4: Recommended Operating Circuit
* Be sure to connect the 4.7 k
resistor within 2.5 cm
from the anode lead end of UV TRON.
UV TRON Driving Circuit C3704 series (Option)
Hamamatsu also provide the driving circuit
C3704 series for R2868 operation.
C3704 series include a high voltage power
supply and a signal processing circuit in
printed circuit board, which allows to
operate R2868 easily as a flame sensor
with the low input voltage (DC 6 to 30 V)
only.
For the details, please refer to the
datasheet of C3704 series.
PRECAUTIONS FOR USE
Ultraviolet Radiation
The UV TRON itself emits ultraviolet radiation in operation. When using two or more UV TRONs at the same time in close position, care should be
taken so that they do not optically interfere with each other.
Vibration and Shock
The UV TRON is designed in accordance with the standards of MIL-STD-202F (Method 204D/0.06 inch or 10g, 10- 500Hz, 15 minutes, 1 cycle) and
MIL-STD-202F (Method 213B/100g, 11ms, Half-sine, 3 times). However, should a strong shock be sustained by the UV TRON (e.g. if dropped), the
glass bulb may crack or the internal electrode may be deformed, resulting in deterioration of electrical characteristics. So extreme care should be
taken in handling the tube.
Polarity
Connect the UV TRON with correct polarity. Should it be connected with reverse polarity, operating errors may occur.
WARRANTY.
The UV TRON is covered by a warranty for a period of one year after delivery. The warranty is limited to replacement of any defective tube due to
defects traceable to the manufacturer.
TPT B0010EA
TPT B0003EA
TPT A0024EA
TPT 1008E01
MAR.1998 CR
Created in Japan
ANODE
CATHODE
90
60
60
30
30
0
90
100%
80
60
40
20
90
60
60
30
30
0
90
100%
80
60
40
20
VERTICAL VIEWING
(Left fig.)
HORIZONTAL
VIEWING
@
(Right fig.)
UV EMISSION
POINT
ANODE
CATHODE
9.0
0.5
8
1
23
1
8
18 MAX.
32 MIN.
44 MAX.
4
CATHODE LEAD
UV GLASS BULB
ANODE
ANODE
CATHODE
ANODE LEAD
12 MAX.
(Side View)
LEAD: 0.7
CATHODE 5 12
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