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

new file 8/20/2019, updated 10/23/2023

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 XOP750w, 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 maybe 50 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.

UPDATE 10/22/2023: The Excelitas EG 9902-1 is similar to the XOP1500 except for having overall length of 392 instead of 395 mm, arc length of 312 instead of 325 mm, bore diameter of 8 instead of 9.4 mm, slightly higher xenon pressure that I estimate as 50 maybe 60 torr, and electrodes made for flashlamp use and that I estimate as being fairly good for average current of .3 amp with flash charge of .7 coulomb (amp-second). I expect even higher flash charge of 1.0 coulomb to be tolerated fairly well with average current of .2 amp, and 1.2 coulombs with average current of .125 amp.

For very long lamp life of several thousand to maybe 10,000 hours of continuous strobe duty usage of EG 9902-1, I recommend not exceeding .7 coulomb per flash with average current not exceeding .18 amp and average lamp power not exceeding 200 watts. And if flash energy is less than 250 joules, I recommend maximum average lamp power being derated linearly from 200 watts at 250 joules to 125 watts at very low flash energy, which means a derating rate of .3 watt per joule. For use without a series inductor I recommend not exceeding (updateed) .95 x the voltage guidelines in here. I recommend generally at least 875 volts, and at most 1350 volts except higher voltage is OK with lower flash energy less than 250 joules.

For use of EG 9902-1 with a series inductor, I estimate Ko as 32.2 ohms-amps^.5 and I recommend going to guidelines in here. Also, I figure 225 instead of 200 watts of average power being easily tolerated long term at higher flash energy of at least 250 watt-seconds, with derating for lower flash energy being at rate of .4 watt per joule.

**PRELIMINARY ESTIMATES** (updated 10/23/2023) Specifications for Flashlamp Use (using an energy storage capacitor):

Lamp                                                XOP-750   XOP-1500  EG 9902-1

Arc length, mm                                         170       325      312
estimated bore diameter, mm                             9.4       9.4      8.0
Estimated Ko, ohms-amps^.5                             14.3      27.2     32.2

Min. Capacitance for nearly-daylight continuous
spectrum both dominant and efficiently produced, uF    1960      1055      667

Minimum voltage for good efficiency at this, V          420       780      875
Charge at Min. Capacitance and Voltage, coulombs       .823      .823     .584
Energy at Min. Capacitance and Voltage, joules          173       321      255

Minimum volts to efficiently produce ion spectrum      ~1000     ~1900   ~2000
Min. Energy for 1/2 of the ultimate efficiency, J      28-36     54-70   45-58

Capacitance for this energy at this voltage, uF        56-72     30-39   22-29
Flash rate for average current of .2 amp, Hz         2.8-3.6   2.7-3.6  3.4-4.5
Flash rate for average current of .3 amp, Hz                            5.1-6.7

A likely good voltage for ion spectrum, volts:         1210      2300    2450
Capacitance for this energy at this voltage, uF        38-49     20-26   15-20
Flash rate for average current of .2 amp, Hz:        3.4-4.4   3.3-4.4  4.1-5.3
Flash rate for average current of .3 amp, Hz:                           6.1-7.9

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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