FAQs | UVTRON^®: Flame / Discharge sensors

UVTRON^® is a sensor sensitive only to UV light with wavelengths of 185 nm to 260 nm (*1).

Featuring high sensitivity and quick response, UVTRON^® is ideal for detecting flame and electrical discharge.

*1: For nickel (Ni) electrodes

What features does UVTRON^® have compared to other sensors ?
Which model of UVTRON^® should I choose ?
Can the sensor also detect cigarettes and incense sticks ?
Can the sensor distinguish the size of a flame ?
Is it possible to use multiple UVTRON^® sensors at the same time ?
What items are needed to operate the sensor ?
What is the best way to measure the supply voltage for UVTRON^® ?
What daily inspection should be performed ?
How long can UVTRON^® be stored ?
Also, what is the best way to check the operation of UVTRON^® after it has been stored for a long time ?
What happens if the supply voltage is changed ?
What is defined as the end of life for the sensor ?
What is the best way to bend the lead wires on UVTRON^® ? Also, what is the best method to cut them ?
What are the precautions when soldering the sensor ?
Is it OK to use a solder bath ?
Should I be careful of the orientation and position when installing UVTRON^® ?
When there are multiple anode leads and cathode leads, do all of them have to be connected ?
Is it OK to set up UVTRON^® far away from the driver circuit ?
What causes background noise (BG) ?
How can I prevent background noise (BG) ?
Also, how do I change the cancellation level ?
What is the intensity of light of the checker lamp ?
Is it OK to use the sensor in high temperature, low temperature, and high humidity environments ?
Why will just dropping the sensor cause it to become defective ?
Can the sensor still be used when dirty ?
Does the sensor comply with each type of certification, directive and regulation ?
I would like to trial use the sensor. Who should I contact ?

光源設置環境について

What features does UVTRON^® have compared to other sensors ?

UVTRON^® is a sensor sensitive only to UV light with wavelengths of 185 nm to 260 nm (*1).

It can detect UV light with high sensitivity and has a quick response when compared with infrared light systems and smoke detection systems.

*1: For nickel (Ni) electrodes

Which model of UVTRON^® should I choose ?

Select the best UVTRON^® model based on the required sensitivity and the conditions where it will be used.

Please refer to the characteristics and specifications.

Can the sensor also detect cigarettes and incense sticks ?

The sensor is sensitive to UV light from flame so cannot detect flameless combustion such as cigarettes and incense sticks.

Can the sensor distinguish the size of a flame ?

Due to the characteristics of UVTRON^®, it is slightly linear in application. Therefore, it is recommended to use it as an ON-OFF sensor to detect the presence of UV light, not as a sensor to measure the intensity of light.

Is it possible to use multiple UVTRON^® sensors at the same time ?

Yes, it is possible.

However, when a UVTRON^® sensor detects UV light, it discharges and emits UV light. Therefore, a neighboring UVTRON^® sensor may detect the UV light emitted from the first sensor. Design the multiple sensor setup so that each UVTRON^® sensor does not cause optical interference with neighboring sensors.

What items are needed to operate the sensor ?

One of the following items are required to operate UVTRON^®.

1. An external CR quenching circuit and a DC high-voltage source

2. A DC-DC converter type high-voltage power supply circuit

At Hamamatsu Photonics, we offer UVTRON^® driver circuits C10807 and C10423 that use a DC-DC converter type high-voltage power supply circuit. Please contact us if you would like more information about this product.

Circuit configuration
for an external CR quenching circuit and a DC high-voltage source

Circuit configuration
for a DC-DC converter type high-voltage power supply circuit

What is the best way to measure the supply voltage for UVTRON^® ?

Use a high impedance multimeter of approximately 10 GΩ to measure the supply voltage for UVTRON^®. If the multimeter does not have enough impedance, it may not be possible to measure the voltage accurately due to the high impedance of the UVTRON^® driver circuit.

Circuit configuration
for voltage measurement circuit with high resistance

What daily inspection should be performed ?

Check whether UVTRON^® detects UV light based on the ON-OFF operation of the checker lamp L9657-03. When doing so, be careful to ensure that UV light from an external source does not enter the UVTRON^® sensor.

How long can UVTRON^® be stored ?
Also, what is the best way to check the operation of UVTRON^® after it has been stored for a long time ?

The warranty period is one year from the date of delivery, and the sensor can usually be stored for approximately five years.

After storing for a long time, check if there is any deterioration of the sensor, such as rust on the lead pins, before checking operation. It depends on how the sensor was stored, but generally, if there is no deterioration such as rust, then there should be no problems with operating the sensor.

What happens if the supply voltage is changed ?

If the supply voltage is increased, sensitivity will increase in proportion to the voltage increase. However, when the supply voltage exceeds the recommended operating range, background noise (BG) increases so it is recommended to use the sensor within the recommended supply voltage range.

Sensitivity characteristics
in relation to the supply voltage
(Typ.)

Background noise characteristics
in relation to the supply voltage
(Typ.)

V_L: Discharge starting voltage under UV light

V_D: Dielectric breakdown voltage between electrodes under fluorescent light

What is defined as the end of life for the sensor ?

The sensor has reached the end of life when any of the following situations occur.

1. When the discharge starting voltage reaches the maximum value in the specifications

2. When sensitivity falls to 50 % of the initial value

3. When background noise reaches the maximum value in the specifications

What is the best way to bend the lead wires on UVTRON^® ? Also, what is the best method to cut them ?

The lead wires can be bent and cut on three sensor types, which are R2868, R9454 and R244. Lead wires on any of the other sensor types must not be processed (cut or bent).

How to bend lead wires

Carefully bend the lead wires after firmly securing them in place to ensure the glass bulb does not break or become scratched.

Good example

Bad example

How to cut lead wires

When processing the lead wires by cutting them, the internal electrodes may be subject to shocks. This may degrade the electrical characteristics to the same extent as if the sensor were dropped. To mitigate these shocks on the internal electrodes, cut the lead wires with the cutting edges of the nippers set perpendicular to the internal electrodes. The lead wires should be cut slowly two or three times using the nippers instead of cutting through the lead wires all at once.

Good example

Bad example

What are the precautions when soldering the sensor ?
Is it OK to use a solder bath ?

Applying excessive heat to the UVTRON^® lead wires during soldering may cause the glass bulb to crack or the internal electrodes to deteriorate. This will lead to faulty operation, so be extra careful when soldering. For the sensors with hard pin lead wires, it is recommended to use one of the dedicated sockets that we provide. When soldering a sensor directly onto a printed circuit board, use heatsink tweezers or a similar tool to grip the root of the lead wires to prevent heat from conducting to the UVTRON^® sensor, and then solder at a temperature of 350 °C or less within 5 seconds. Avoid using a solder bath. When finished soldering, be sure to completely wipe away the soldering flux with alcohol, etc.

Should I be careful of the orientation and position when installing UVTRON^® ?

In terms of the orientation when installing the sensor, view characteristics are listed in the product information section. Refer to this information when installing the sensor to ensure that UV light can directly enter the cathode (photocathode).

There are no restrictions concerning the position when installing the sensor.

When there are multiple anode leads and cathode leads, do all of them have to be connected ?

As long as one of each of the anode leads and cathode leads are connected, the sensor will operate without any problems.

Is it OK to set up UVTRON^® far away from the driver circuit ?

If UVTRON^® must be installed far away from the driver circuit and the cable capacitance exceeds 100 pF, insert a current limiting resistor (R_S: 4.7 kΩ) immediately before (within 25 mm) the UVTRON^® anode.
If the cable has a high stray capacitance, the discharge current will also be high, which may damage the electrodes.

Circuit configuration for an external CR quenching circuit

・When installing UVTRON^® far away

What causes background noise (BG) ?

Cause of background noise (BG) include the following:

1. Radiation including cosmic rays

When radiation with higher energy than UV light is incident on the cathode (photocathode), a discharge can be caused due to the photoelectric effect. As it is difficult to completely prevent the entry of radiation such as cosmic rays, which exist in nature, it is necessary to use a signal processing circuit to distinguish it from UV light from a detection target.

2. X-rays

When X-rays with higher energy and penetrating properties than UV light is incident on the cathode (photocathode), a discharge can be caused due to the photoelectric effect.

3. Static electricity

When an object charged with static electricity comes close to or makes contact with UVTRON^®, the high electric field may ionize the gas molecules in the tube and cause a discharge.

4. High electric fields, high magnetic fields, and strong electromagnetic waves

Under high supply voltage conditions, the electric field emission from the cathode (photocathode) may cause photoelectrons to jump out, and this may trigger a discharge.

5. Intense light (such as from lasers and LEDs) with extremely high radiant intensity greater than sunlight

When intense light with extremely high radiant intensity is incident on the cathode (photocathode), background noise can increase due to thermionic emission and other factors.

6. Unintentional UV light

While this is normal for UVTRON^® operation, UV light from sources other than a detection target may cause the device to malfunction. This also can be considered as a type of background noise (BG). UV light is also found abundantly in ordinary life. Especially outdoors, UVTRON^® reacts to faint UV light from unexpected sources, such as sparks from arc welding or electrical sparks (sparks from a train pantograph). Take sufficient precautions for the area where UVTRON^® is installed and used.

How can I prevent background noise (BG) ?
Also, how do I change the cancellation level ?

Be careful to ensure that unintended UV light does not enter the sensor. However, since it is not possible to avoid UVTRON^® from reacting to the effects of cosmic rays, it is recommended to use a signal processing circuit that cancels background noise (BG). Our UVTRON^® driver circuit C10807 and C10423 are equipped with background noise (BG) cancelling functions. Please contact us if you would like to change the cancellation level.

Signal processing circuit configuration

What is the intensity of light of the checker lamp ?

The lamp emits UV light that is similar in intensity to a lighter.

The lamp is considered to be harmless according to IEC62471 “Photobiological safety of lamps and lamp systems.” However, avoid directly looking into the lamp with the naked eye for long periods of time.

Is it OK to use the sensor in high temperature, low temperature, and high humidity environments ?

Be sure to keep to the specified operating temperature range of -40 ℃ to +125 ℃ and operating humidity range of 80 % or less when using UVTRON^®.

The following tends to occur when using the sensor in high temperature, low temperature, and high humidity environments.

● Under high temperature, the sensor deteriorates faster.

● Under low temperature, the discharge starting voltage under UV light (VL) drops and sensitivity increases.

● Under high humidity, operation becomes unstable due to voltage leaks and short circuiting.

If operating humidity exceeds 80 %, ensure that no moisture forms on the sensor. Also, be careful to ensure there is sufficient insulation around the lead wires, such as covering the lead wires with insulating resin.

Why will just dropping the sensor cause it to become defective ?

Because excessive shock on UVTRON^® may cause the anode and cathode to come into contact with each other, which can significantly shorten its lifespan.

Can the sensor still be used when dirty ?

If the glass bulb is dirty, UV light transmittance will drop and this may cause the glass to deteriorate. After installing the sensor onto equipment, periodically wipe the glass bulb with gauze or cleaning wipes moistened with alcohol to keep it clean. When handling UVTRON^®, do not touch the glass bulb with your bare hands. Wear gloves to prevent oil and grime from your hands sticking to the glass bulb.

Does the sensor comply with each type of certification, directive and regulation ?

The UVTRON^® sensor, socket, and checker lamp are not covered by CE certification. However, the UVTRON^® driver circuit, checker lamp driver circuit, and module comply with CE certification.

All of these products comply with the RoHS directive.

Please contact us for information about the REACH regulation.

I would like to trial use the sensor. Who should I contact ?

We provide free demo units on loan for trial use. Please contact us for more information any time.

Contact us for more information.

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FAQs | UVTRON®: Flame / Discharge sensors

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光源設置環境について

What features does UVTRON® have compared to other sensors ?

Which model of UVTRON® should I choose ?

Can the sensor also detect cigarettes and incense sticks ?

Can the sensor distinguish the size of a flame ?

Is it possible to use multiple UVTRON® sensors at the same time ?

What items are needed to operate the sensor ?

Circuit configuration for an external CR quenching circuit and a DC high-voltage source

Circuit configuration for a DC-DC converter type high-voltage power supply circuit

What is the best way to measure the supply voltage for UVTRON® ?

Circuit configuration for voltage measurement circuit with high resistance