# FAQs | Xenon flash lamps

### How are the maximum lamp input energy (per flash) and the maximum repetition rate of a lamp calculated?

Refer to the following equations:

For example, when operating a 20 W xenon flash lamp at a main discharge voltage of 1000 V using a recommended power supply C13316-10 (main discharge capacitance: 1.0 μF (10-6 F) ), the maximum lamp input energy (per flash) is 0.5 J as calculated by the following equation:

In the above case, the maximum repetition rate of the 20 W xenon flash lamp is 40 Hz as calculated by the following equation:

When selecting a lamp, the maximum lamp input energy and maximum repetition rate must be taken into account so that the maximum average lamp input (continuous) will not exceed the rating.

### What happens if a lamp is used at a main discharge voltage higher than its rating?

The electrodes will wear down faster, and this will shorten the life of the xenon flash lamp.
Be sure to use the lamp under the operating conditions within the specified rating.

### What happens if a lamp is used at a repetition rate that exceeds the maximum repetition rate?

The lamp will not emit light at the desired lamp input energy.
The electrodes will also be damaged by continuous lighting, and the life of the lamp will be shortened.
Be sure to use the lamp under the operating conditions within the specified rating.

### How do the characteristics change depending on the arc length?

Xenon flash lamps with a long arc length provide higher light output with a wider flash pulse width (longer flash duration) and are ideal for applications that require a large irradiation area. On the other hand, xenon flash lamps with a short arc length emit higher brightness light and are used for applications that require higher accuracy.

Emission pulse waveform (Typ.)

Brightness characteristics (Typ.)

### How do the characteristics change depending on the main discharge capacitance?

The larger the main discharge capacitance, the greater the maximum lamp input energy. This will produce a higher light output with a wider flash pulse width (longer flash duration).

Emission pulse waveform (Typ.)

### How do the characteristics change depending on the main discharge voltage?

The higher the main discharge voltage, the greater the maximum lamp input energy and the higher the light output that can be obtained. Unlike the main discharge capacitance, the flash pulse width (flash duration) does not change.

Emission pulse waveform (Typ.)

### What type of trigger signal input is needed from signal source in order to operate xenon flash lamp module or power supply for xenon flash lamp?

Input rectangular wave signal referring to the repetition rate and trigger signal on each specification page.
(Operation at 10 Hz or more is recommended for high stability)
In addition, use signal source for trigger signal input that can output 15 to 30 mA.

Trigger signal waveform

Internal circuit diagram example of trigger signal input section

### Is there any difference in life characteristics for each wavelength?

In general, the light output on the short wavelength side tends to decrease significantly.
The lamp life is defined as the time when the light output at 190 nm to 1100 nm decreases to 50 % of the initial output level or the light output fluctuation exceeds the specified maximum value.

Life characteristics (Typ.)
Examples: 2 W xenon flash lamp modules

### Is there any difference in life characteristics at each lamp input energy (energy per flash)?

In general, the larger the lamp input energy (energy per flash), the shorter the life.

Life characteristics (Typ.)
Examples: 10 W xenon flash lamp

### What should be done to ensure the lamp to be operated stably?

Following solutions are recommended:

① Use the light in the center of the arc.
The light output stability of a xenon flash lamp differs depending on the arc discharge measurement position. The closer to the center of the arc, the more stable the light output.

Light output stability with respect to arc discharge measurement position (Typ.)

② Do not use the light at the initial lighting.
Highly stable output light can be obtained from a xenon flash lamp by avoiding the warm-up time (time taken to reach stable operation) at the initial lighting.

Light output stability with respect to operating time (Typ.)

Initial operation

After 5 seconds of operation

③ Average the data.
Light output stability is improved by processing and averaging multiple acquired data.

Light output stability for data processing (Typ.)

Without data processing

With data processing

(average value of multiple acquired data)

### What device setup is used to measure the spectral distribution, emission pulse waveform and life characteristics of xenon flash lamps?

Typical measurement setups are as follows:

Spectral distribution

Emission pulse waveform

Life characteristics

### What devices are needed to operate a lamp?

Prepare the following devices:

#### ○ Operating a xenon flash lamp module

##### Required:

・DC power supply (input power)

・Pulse signal source such as a pulse generator (for external control of maximum repetition rate)

##### Optional:

・External control power supply (external control of main discharge voltage)

#### ○ Operating a xenon flash lamp using a trigger socket and dedicated power supply

##### Required:

・DC power supply (input power)

##### Optional:

・Pulse signal source such as pulse generator (for external control of maximum repetition rate)

・External control power supply (external control of main discharge voltage)

### What is an important factor when selecting an optical fiber?

Be sure to select an optical fiber that is resistant to UV light.

### Are there any restrictions on the direction for installing a xenon flash lamp?

Installing a lamp with its light output window facing downward is not recommended.
Debris particles from the inside of the lamp may adhere to the light output window, causing a drop in the light output.

### What should be checked before using a xenon flash lamp that has been stored for a long time?

Check the lead pins for any deterioration such as rust before checking the operation.
Although depending on how the lamp has been stored, there will be basically no problems with operating it unless deterioration such as rust is found on the lead pins.

### Is it possible to change the cable length of the trigger socket?

The cable length of the trigger socket affects the flash pulse width (flash duration) and lamp input current.
When the cable length is increased, the flash pulse width becomes longer and the lamp input current tends to decrease, which might cause the lamp to fail to light up.
When the cable length is reduced, the flash pulse width becomes shorter and the lamp input current tends to increase, which might shorten the lamp lifetime.
Therefore, changing the trigger socket cable length is not recommended.

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