Vacuum Ultraviolet Monochromator Spectrograph

Vacuum Ultraviolet Monochromator/Spectrograph

McPherson 219 Vacuum Ultraviolet Monochromator/Spectrograph 0.5 meter with Gratings

We no longer offer this product. If you want repair service or a custom modern equivalent, contact us.

This is a McPherson Inc. Model 219 vacuum ultraviolet (VUV) corrected Czerny-Turner Monochromator/Spectrograph. Included are:

  • Adjustable input slit
  • 1200 line/mm, 500 nm, 50x50 mm, Snap-In Grating Has non-removable smudges.
  • 1200 line/mm, 750 nm, 50x50 mm, Magnesium Fluoride Snap-In Grating Has minor scratches parallel with lines.
  • User Manual

Note: grating rotation can be controlled by side mounted adjustment knob or on-board stepper motor. If you would like assistance selecting an appropriate stepper drive please contact us.

The Model 219 is a 500-mm focal length f/8.7 vacuum monochromator. It features the McPherson patented Corrected-Loci (US Pat. 3490848) optical design and uses Snap-In Gratings (US Pat. 3433557). It comes standard with a manual grating rotation drive and a wavelength counter accurate to 0.1 nm. Grating rotation can also be controlled by on-board stepper motor. The grating holder accepts 50 x 50 mm plane Snap-In gratings and can alternately be used with 68 x 68-mm gratings.

A bilaterally adjustable entrance slit is provided with a range of 10 microns to 4 mm. (4000 microns.) The slit control knob has twenty graduations, each representing 20 microns. A mechanical stop prevents the slit jaws from closing below 5 microns. Slit height is adjustable from 0 to 20 mm.

The vacuum tight housing is internally welded. All the instruments moving parts are outside the chamber to insure clean, easy evacuation. A large 6-inch focusing mirror delivers a 100-mm wide focal plane at the exit port. The optics in this instrument are coated with Al+MgF2 enhancing the vacuum UV response.

Many available accessories allow this instrument to be configured as a monochromator, spectrograph, or polychromatic. It will accept CCD, microchannel plate, film and even multi-channel polychromatic attachments with up to six 1-inch side on PMTs.


  • Czerny-Turner design
  • Internally welded, vacuum tight housing.
  • Al+MgF2 coated optics for enhanced UV response
  • Corrected-Loci optical design
  • Snap-In Gratings


Mirror Type


Slit Length

0 to 20 mm

Slit Width

0.005 to 2 mm

Wavelength Range at Focal Plane

168 nm

Wavelength Reproducibility

±0.005 nm (with 1200 line/mm grating)

Wavelength Range

105 nm to 1.2 μm (with 1200 line/mm grating)

Wavelength Accuracy

±0.10 nm (with 1200 line/mm grating)

f Number


Grating Size

50 x 50 mm

Angle Between Entrance and Exit Beams

180 °

Maximum Focal Plane

100 x 35 mm


1.66 nm/mm

Flange Type

9 in OD, 5 in ID, ASA


0.04 nm (with 1200 line/mm grating at 313.1 nm)

Focal Length

500 mm