337ND‎ > ‎

337ND-S Cartridge

Reusing the components from the type of LSI nitrogen laser cartridge which has attached mirrors

Spectra-Physics PART NO. 337291 PLASMA CARTRIDGE NO. 5X13585.

The HR.

The OC.

There are four main caps, and two peaker caps, all the same (schematic below).


An iButton DS 1994 (silvery can on the inside wall), with single wire serial data interface sticking through to the outside.

The red wire goes to the iButton.

The PCB (under the front of the tube) comprises a voltage divider, apparently to activate the iButton.

Here, the mirrors have been attached to a plexiglass support for the cartridge components.  There is an
HeNe alignment laser in the background, and the beam from the N2 is aligned to coincide with the hole in the cardboard through which the alignment beam passes.

Four-screw and six-screw LSI tubes with valves attached for refilling.

Note on top of the tube behind the OC mount, is a gas fill valve
from the hardware store plumbing department.  The tube seems to hold vacuum OK;  I put roughly 60 torr of N2 in it a few weeks before.  It's bright enough to lase dye (R6G in ethyl alcohol on the right).

Here, I'm running the original 337ND tube (foreground) with the HV from the 337ND (right), to compare the tube I filled myself with a professional refurb.   Because the old spark gap free-runs, I have no control over pulse rate.  Result:  The beam starts out bright, then dims to almost nothing within a few minutes (see my investigation of this at N2 Gain Medium Depletion).  It's shown here shortly after turning it back on after a 1/2 hour break, and the N2 has recovered.