Xenon Flashlamps
  • Excellent sources of low to medium power UV-NIR CW radiation
  • Minimize unwanted sample excitation
  • High ultraviolet peak power
  • Short pulses allow time resolution
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Description Models Catalog PDF
6426 and 6427 Xenon Flashlamps, with 68826 Power Supply.

More UV than CW Arc Lamps

Arc lamps are the brightest continuous radiation sources available (excluding lasers). The plasma in the xenon and mercury lamps has temperatures of more than 5500 K. The higher the plasma temperature the more total output and particularly the greater the short wavelength output. Increasing the plasma temperature of continuous arc lamps by increasing the current density (lamp power) quickly destroys the lamp. Expensive attempts to make lamps with more UV output, either through plasma seeding or plasma confinement, have not resulted in a practical solution. With continuous lamps, you can only enhance the output briefly in short pulses superimposed on a background. With flashlamps, this short burst, high plasma temperature option is available without the expense of continuous arc technology (Fig. 1). This only holds for the short flash, but that's long enough for many applications.

Fig. 1 shows the output from our 6427 Flashlamp, operated at 60 Hz, 1J (60 W average), by the 68826 Power Supply and the output of a 75 W Xe continuous arc lamp. The 75 W lamp provides higher average irradiance above 280 nm. The pulsed lamp produces much higher peak irradiance at all wavelengths.


Fig. 1 Comparison of average irradiance at 0.5 m from the 6251 75 W xenon DC arc lamp and the 6427 Large Bulb Flashlamp running at 60 Hz (60 W average).

The Short Pulse

Flashlamps radiate for a very short time; our lamps emit for several microseconds; maximum flash rates are tens of hertz. Utilization of a short pulse source allows temporal studies. You can illuminate quickly and follow the time course of the effect produced. The “effect” could be as simple as reflected radiation for freeze frame photography. Short flashlamp pulse illumination of a scene “freezes” any motion. Repeated illumination at known intervals allows quantification of rate of change.

Short pulses can be used to measure the decay of fluorescence or phosphorescence, identifying species through the characteristic “lifetime”. Pulse excitation or probing makes many kinetic studies possible and has obvious applications to flowing systems, dissolution studies and in following chemical reactions.

Steady illumination of many chemicals poses problems of sample heating, bleaching, etc; in some systems, molecules accumulate in long-lived states such as triplet states with forbidden transitions to ground. Continuous sources are not suitable for luminescence studies of these systems. With our flashlamp sources, each pulse effectively excites a fresh sample; there is no build up of long-lived species to mask the direct excitation under study. Short flash illumination allows extraction of information before triplet build up and allows studies of triplet cross over.

Guided Arc Lamp

This small bulb lamp, model 6426, uses arc guiding electrodes to ensure repeatable arc paths. We solder the bulb contacts to the trigger circuit board for highest reliability. The stability of the light output is excellent with a variation of less than 2%. The side emitting bulb has a 3 mm arc gap and a fused silica envelope for highest UV output. Arc dimensions are 3 x 2.5 mm. Maximum pulse energy is 0.32 J. We operate this lamp to 100 Hz. Lamp life is greater than 108 flashes.


Fig. 2 Pulse shape of 6426 Xenon Flashlamp.

5 J Large Bulb Lamp

This rugged lamp has a 3 mm electrode gap. The lamp radiates from an intense 3 x 2.5 mm volume, and the envelope is high quality fused silica. You can operate this lamp from low frequencies up to 60 Hz. The input pulse energy, 5 J at frequencies up to 12 Hz, falls to 1 J at 60 Hz. This doesn’t greatly influence the spectral distribution and average irradiance, but the spectral energy density produced by each pulse follows Fig. 3.


Fig. 3 Pulse shape of 6427 Xenon Flashlamp.

A Note About EMI

Arc lamp ignition requires high voltage, high frequency pulses to break down the lamp, and a high current discharge to sustain the arc. Ignition creates significant electromagnetic energy, which may occasionally interfere with associated equipment. Even EMI proofed circuits may require extra attention to earthing, cable routing and EMI shielding, to avoid ignition interference. Interference may be more problematic with a pulsed arc lamp system as each pulse requires lamp ignition.