Protocol for the SPEX 1250M Monochromotor
By: Chris Dennis
Created: 2008
To record beautiful spectra a proper understanding of the equipment and theory of fluorescence
spectroscopy is tantamount. This manual is intended to guide the user by outlining the most basic
procedures for operating this equipment well. It is advised that the user consult the user’s manual and/or
spectroscopy texts for any further information and troubleshooting.
Equipment
The SPEX 1250M is supplemented by many peripheral instruments listed below
 A/D Converter (SpectraAcq2)
 Motor Control Unit
 High Voltage Power Supply (for PMT)
 Lock-In Amplifier (used for IR detection)
 Reference and Input Chopper (for use with the lock-in amplifier)
 Tektronix Oscilloscope (multi-purpose)
 Personal Computer
Take a moment to review the pictures of the setup.
1. Configuration for IR or Visible Spectroscopy (Zen and the Art of Diffraction Gratings)
Before you run your scan you must first decide which diffraction grating cooresponds to your desired
wavelength range. The lab carries 3 diffraction gratings for the SPEX1250M.

300 grooves/mm Blazes at 3000nm

600 grooves/mm Blazes at 1500nm

1200 grooves/mm Blazes at 500nm
To switch out the gratings physically you must first remove the diffraction grating housing cover located
on the top of the SPEX1250M. Once you remove the four screws you will immediately see the
diffraction grating turret. To remove the diffraction grating from the turret you must locate the securing
lever on the back of the turret. Flip this lever down to release the grating. Now place your new grating
into the turret and secure it in place with the lever. It should fit in easily, never force it in. Once you are
in the software you must tell the software which grating you are using. I will walk you through that
procedure when we get to the software setup section.
2. Preparing the IR Detector
The IR detector must be cooled with liquid nitrogen. Place liquid N2 into the detector and let the detector
cool down. You can tell when it has cooled down when the gas stops expelling from the detector. You
will then need to put more Liquid N2 into the detector. You may need to periodically refill the detector.
3.
Powering Up
The order of powering up the equipment is extremely important. Power surges from high voltage/high
amperage equipment can ruin sensitive devices. Be sure that all entrance and exit slit on the
monochromator are closed.
Visible:
a.
b.
c.
d.
Turn on the Excitation Source (Laser, Tungsten Lamp, etc)
Next, turn on the High Voltage Power Supply (950V)
Next, turn on the SPEX1250M
Finally, turn on the Computer
a.
b.
c.
d.
e.
Turn on the Excitation Source (Laser, Tungsten Lamp, etc.)
Next, turn on the SPEX1250M
Next, turn on the Lock-In Amplifier
Next, turn on the Chopper
Finally, turn on the Computer
Infrared:
4.
Using the Origin based SynerJY Software (Data Acquisition)
Once the power-on procedure is completed and the computer is running go ahead and click on the
‘SynerJY’ icon to start the data acquisition program. The program should load and you should see this
screen. Click the button that looks like a graph (circled in the picture) to begin setup. The following
slides will guide you the rest of the way.
Detector Selection Screen
5. Saving your data and hard work!
Once your spectrum is complete it is likely you will want to transfer this data to another computer or
media. To do so follow the simple instructions outlined below.