XOP-750, XOP-1500, XOP-7 and XOP-15 Xenon Lamps

new file 8/20/2019

The XOP750 and XOP1500 are linear xenon lamps that are generally used for strobe use, usually in specific stage lighting equipment designed to use them. The XOP760w, XOP1500W, ZB-1500, XOP-7 / XOP7-OF and XOP-15 / XOP15-OF are the same or similar. The 7 and 750 versions are nominally 750 watt lamps approximately 240 mm or 9.45 inches long, the 15 and 1500 versions are nominally 1500 watt lamps approximately 15.55 inches or 395 mm long.

The two main electrodes appear identical and there are no polarity markings, so these lamps can be operated in either polarity.

The electrodes appear designed for hot cathode arc lamp duty at a current of a few or several amps.

The electrodes also appear capable of handling short duration high current strobe pulses in cold cathode mode with peak current preferably in the 100s of amps, using an energy storage capacitor, and average current up to about .2 amp (???). My preliminary recommendations for long life expectancy in such use:

Up to this much average current,   With up to this much flash charge,
amps                               coulombs

  .2                                 .125
  .1                                 .2
  .05                                .25

The usual equipment that uses these lamps does not work them in a comfortable hot cathode manner or a comfortable cold cathode manner. Life expectancy of these lamps in many usual devices that use them is often short, at least sometimes specified as only 250-500 hours. The longer length of the XOP 15 / 1500 lamps is advantageous so that a smaller percentage of the lamp's arc length (or arc gap distance) is obscured by discoloration / blackening of the ends (electrode regions) of the lamp.

The xenon pressure is low; my preliminary estimate of the xenon pressure at room temperature is 40 torr. The low xenon pressure means low efficiency. One advantage of the low xenon pressure is that in cold cathode high peak current flashlamp use, lower flash energy or pulse energy than usual (for lamps as large as the XOP-750 and XOP-1500) can be used and these lamps will still flash with a majority of their ultimate efficiency.

**PRELIMINARY ESTIMATES** Specifications for Flashlamp Use (using an energy storage capacitor)

Lamp                                                 XOP-750       XOP-1500

Arc length, mm                                          170           325
estimated bore diameter, mm                             9.4           9.4
Estimated Ko, ohms-amps^.5                             14.3          27.2

Min. Capacitance for nearly-daylight continuous
spectrum both dominant and efficiently produced, uF    2000          1055

Minimum voltage for good efficiency at this, V          475           900
Charge at Min. Capacitance and Voltage, coulombs        .95           .95
Energy at Min. Capacitance and Voltage, joules          225           427

Minimum volts to efficiently produce ion spectrum      ~1000         ~1900
Min. Energy for 1/2 of the ultimate efficiency, J      28-36         55-70

Capacitance for this energy at this voltage, uF        56-72         30-39
Flash rate for average current of .2 amp, Hz           5.4-7         5.4-7

A likely good voltage for ion spectrum, volts:         1210          2300
Capacitance for this energy at this voltage, uF        38-49         21-27
Flash rate for average current of .2 amp, Hz:         6.5-8.5       6.5-8.5

CAUTION: The XOP-750 and XOP-1500 lamps and the like produce shortwave and mediumwave ultraviolet (UVC and UVB), although (at least usually) little or no ozone-producing UV. These lamps are normally used with glass shields to block UVB and UVC.

Written by Don Klipstein.

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