Resonance VM200 User manual

615 –VM200 VUV Monochromator/ Spectrometer
Operating Manual
www.resonance.on.ca

TABLE OF CONTENTS
TABLE OF CONTENTS............................................................................................................................. 2
TABLE OF FIGURES ................................................................................................................................. 3
GENERAL INFORMATION...................................................................................................................... 4
SYSTEM OVERVIEW.................................................................................................................................. 4
PACKING LIST........................................................................................................................................... 5
SETUP........................................................................................................................................................... 6
SYSTEM OPERATION .............................................................................................................................. 7
OPERATING IN MONOCHROMATOR MODE............................................................................................... 7
PERFORMING A SCAN................................................................................................................................ 8
OPERATING IN SPECTROMETER MODE .................................................................................................... 9
OBTAINING SPECTRA................................................................................................................................ 9
MOUNTING AND OPERATING WITH A LAMP.................................................................................11
CALIBRATING THE MONOCHROMATOR........................................................................................12
FOCUSING THE VM200...........................................................................................................................13
IN MONOCHROMATOR MODE..................................................................................................................13
IN SPECTROMETER MODE........................................................................................................................14
ADD-ON OPTIONS....................................................................................................................................15
APPENDIX:.................................................................................................................................................16
SYSTEM COMPONENTS ............................................................................................................................16
Monochromator ..................................................................................................................................16
Photodiode Detector............................................................................................................................17
CCD.....................................................................................................................................................17
Adjustable Slits....................................................................................................................................18
NIST CALIBRATION.................................................................................................................................19

TABLE OF FIGURES
FIGURE 1: CUTAWAY VIEW OF VM200 ........................................................................................................... 4
FIGURE 2: MOTOR DRIVE CONTROLLER BOX.................................................................................................. 7
FIGURE 3: DETECTOR CONNECTIONS .............................................................................................................. 7
FIGURE 4: PHOTODIODE INDICATOR LIGHTS &ZERO BUTTON........................................................................ 8
FIGURE 5: SLIT WIDTH ADJUSTMENT MICROMETER ....................................................................................... 8
FIGURE 6: CCD USB PORT ............................................................................................................................. 9
FIGURE 7: CCD INDICATOR LIGHTS &ZERO BUTTON .................................................................................... 9
FIGURE 8: SLIT WIDTH ADJUSTMENT MICROMETER ......................................................................................10
FIGURE 9: EXAMPLE OF CCD SIGNAL LEVEL NON-LINEAR EFFECT.................................................................10
FIGURE 10: EXIT SLIT FOCUSING COLLAR AND FASTENING SET-SCREW..........................................................13
FIGURE 11: CCD FOCUSING COLLAR AND FASTENING SET-SCREW.................................................................14
FIGURE 12: GRATING EFFICIENCY CURVE.......................................................................................................16
FIGURE 13: TYPICAL RESPONSE CURVE OF THE AXUV PHOTODIODE.............................................................17
FIGURE 14: TYPICAL RESPONSE CURVE OF THE HAMAMATSU S9840 CCD ....................................................18
FIGURE 15: NIST STANDARD CALIBRATION CURVE......................................................................................19
FIGURE 16: NIST CALIBRATION MEASUREMENTS .........................................................................................19
FIGURE 17: NIST TRACEABLE QUANTUM EFFICIENCY CHART ......................................................................20

GENERAL INFORMATION
SYSTEM OVERVIEW
The Resonance Ltd. monochromator/spectrometer is designed for laboratory applications
yet is rugged enough for field use. The system is hermetically sealed and can be used in the
vacuum ultraviolet region (wavelengths below 190 nm) with a nitrogen or helium purge, or
by connecting to a vacuum system either through the slits or through a 2.75" Conflat® style
flange on its base. The compact size of the unit results in a small internal volume (only 2
litres), allowing for a rapid pumping time.
A single grating is used to maximize throughput in the vacuum ultraviolet region and to
minimize scattered light. The standard grating is a 45mm square f/4.2 concave
holographic grating with an aluminum/MgF2 overcoat. The reflective properties of this
or any grating can be severely damaged by mechanical contact with any solid, liquid or
vapor. Never blow on the surface of the grating or onto the slit openings.
Figure 1: Cutaway view of VM200
Concave Holographic
Grating
Entrance Slit
Exit Slit
2 ¾” CF Flange
pumping port

PACKING LIST
Below is a list of all the components shipped with the VM200. If you find any of these
items to be missing, please contact Resonance Ltd. to arrange to have it delivered.
Item Quantity
VM200 Monochromator 1
Motor Drive Electonics Box 1
EUV Si Diode 1
CCD Array 1
18 VDC Power Supply 1
5 VDC Power Supply 1
Software Disc 1
LabJack 1
USB Cable 1
BNC Cable 1
2 ¾” Viton Gasket 1
2 ¾” Copper Gasket 1
018 Viton O-rings 3
¼ - 28 x 1” SS socket head bolts 6

SETUP
The VM200 is supplied with either an exit slit, to allow use of the system as a
monochromator, or a CCD for spectrometer operation or both.
In monochromator mode, a detector can be mounted at the exit slit either by a 2 ¾” CF
flange or a 1”-20 thread with a shoulder to hold and compress the o-ring (if vacuum
operation is required). In spectrometer mode, the CCD module is mounted in the place of
the exit slit using 4 4-40 x 1 ½” stainless steel socket head cap screws.
The VM200 spectrometer can be fixed in any orientation and attached to a VUV light
source that attaches to a CF flange or a 1”-20 thread with a shoulder to hold and
compress the o-ring for vacuum operation. If purged operation is desired, an adaptor
flange can be used to allow purge gas to enter the spectrometer through the flange at the
bottom of the spectrometer and exit the entrance slit. Vacuum or purged operation is
necessary only when observing wavelengths less than 190 nm. Keep in mind that the
VUV properties can be easily damaged by organic contaminants therefore use only oil-
free purge gas.
For mounting to a purge system, light source, or detector a standard CF flange that
screws directly onto the 1”-20 at the base has been supplied (see Figure 1). If a CF flange
is not compatible with the system, any counter-bored flange design (NW, ASA, etc) with
a female 1”-20 tpi thread adaptor with a shoulder to hold and compress the o-ring can be
used. Since the design of the interface to a lamp will depend on the lamp design, we have
supplied one 2.75” CF type flange, which screws directly onto the 1”-20 flange to allow
maximum adaptability.
Note: if while mounting the threads bind, do not force any further. The piece may
be loosened by applying a small amount of isopropyl alcohol to the bottom of the
thread. After capillary action has drawn the liquid up into the thread the piece may
be unscrewed.

SYSTEM OPERATION
OPERATING IN MONOCHROMATOR MODE
1. Plug the motor cable into the motor drive controller box
Figure 2: Motor Drive Controller Box
2. Plug in the driver box power supply
3. Plug in the USB cable
4. Plug in the LabJack USB cable
5. Connect the detector BNC cable from the detector signal output to the LabJack
6. Plug in the detector power supply
Figure 3: Detector Connections

7. Start the Program
8. Make sure the ‘Stepper’ and ‘Photodiode’ indicator lights both turn green
9. Click on the ‘Zero’ button
Figure 4: Photodiode Indicator Lights & Zero Button
1. You are now ready to obtain spectra
PERFORMING A SCAN
1. Set the slits to the desired width for the ideal signal vs resolution. Note: There is
backlash in the micrometer dial, so it is best to completely close the slits (to
approximately 10 micron below zero) and then open them to the desired
width, otherwise the set slit width may not match the actual width.
Figure 5: Slit Width Adjustment Micrometer
2. Enter the desired starting wavelength for the scan in the box
3. Enter the desired ending wavelength for the scan in the box
4. Set the scan speed/step resolution by moving the sliding bar to the desired step
increment
5. Click on the button
Indicator lights

OPERATING IN SPECTROMETER MODE
1. Repeat steps 1-3 from monochromator mode
2. Plug in the CCD USB cable
Figure 6: CCD USB Port
3. Start the program
4. Make sure the ‘Stepper’ and ‘CCD’ indicator lights both turn green
5. Click on the ‘Zero’ button
Figure 7: CCD Indicator Lights & Zero Button
6. You are now ready to obtain spectra
OBTAINING SPECTRA
1. Set the entrance slit to the desired width for the ideal signal vs resolution. Note:
There is backlash in the micrometer dial, so it is best to completely close the
slits (to approximately 10 micron below zero) and then open them to the
desired width, otherwise the set slit width may not match the actual width.
Indicator lights

Figure 8: Slit Width Adjustment Micrometer
2. Set the integration time and the number of averages to the desired levels. (Note:
at higher signal levels [>2000 counts] the CCD begins to respond non-
linearly, resulting in the appearance of loss of resolution and a rounded peak,
therefore it is idea to adjust the integration time to keep the signal to a
reasonable level).
Figure 9: Example of CCD signal level non-linear effect
3. Enter the desired center wavelength in the box at the bottom of the
screen and click the button
4. If it appears that the actual center wavelength does not match the wavelength
entered, there is a CCD centre offset function in the settings tab
() that allows the user to compensate for this. Due to some non-
linear effects within the system, this offset may need to be adjusted based on the
centre wavelength setting.
5. To remove the dark spectrum from the measured signal, turn off the light source
and click on to store it to memory and on to subtract
it from the displayed signal.
6. Turn the light source back on
Rounded peak &
appearance of
loss of resolution
due to CCD non-
linear effect

7. Click on the button to save the spectrum to memory
to allow it to be recalled at a later point during the test run (Note: Memory is
cleared once the program is closed)
MOUNTING AND OPERATING WITH A LAMP
Any of the several Resonance VUV lamps may be screwed directly onto the 1”-20 thread
at the spectrometers entrance slit to bring the as close to the slit as possible. For other
light sources, a 2 ¾” CF adapter flange with ¼”-28 threaded holes has been provided to
allow easy coupling to the system. When mounting to the 1”20 thread, carefully remove
the CF flange (if applicable) from the entrance slit and attach the lamp ensuring the o-
ring is compressed. NOTE: if high vacuum is unattainable, check that the front o-ring or
gasket is fully compressed and has not been pinched.

CALIBRATING THE MONOCHROMATOR
It is possible that occasionally the wavelength scale may need recalibration. To do this, 3
known wavelengths are required, ideally with two of them near the far ends of the
wavelength scale.
1. With the light source one, scan across the spectrum
2. Note the locations of the known wavelengths by either setting the plot cursors on
the peaks or noting separately the wavelength of the peak as accurately as
possible
3. Go to the ‘Settings’ tab
4. If the wavelengths were recorded using the plot cursors:
a. Enter the three known wavelengths into the λ1, λ2and λ3 boxes in the
‘Spectrometer Wavelength Calibration’ section
b. In the ‘Grab Cursor’ drop-down box, select the first plot cursor
c. Click on the ‘Grab’ button next to the according known wavelength. The
step location of the plot cursor should appear in the ‘Step @’ box next to
the button.
d. Repeat this process with for the other two wavelengths
e. Click on the ‘Calculate’ button
f. A notice box should appear indicating that the coefficients have been
changed and the system needs to be re-zeroed. Click ‘OK’
g. If no mistakes have been made and you are confident of new coefficients,
click the ‘Save Settings’ button and then zero the monochromator
5. If the wavelengths were recorded separately:
a. In the ‘Conversions’ section, convert the three recorded wavelengths to
step number
b. Enter the three known wavelengths into the λ1, λ2and λ3 boxes in the
‘Spectrometer Wavelength Calibration’ section
c. Manually enter the obtained step number for each of the wavelengths
d. Click on the ‘Calculate’ button
e. A notice box should appear indicating that the coefficients have been
changed and the system needs to be re-zeroed. Click ‘OK’
f. If no mistakes have been made and you are confident of new coefficients,
click the ‘Save Settings’ button and then zero the monochromator
6. Perform another scan to ensure the wavelength scale is now accurate. Repeat the
process if necessary

FOCUSING THE VM200
If for some reason you suspect that VM200 may need to be refocused, this can be done
using either the detector for in monochromator mode, or the CCD in spectrometer mode.
Focusing is done much quicker and simpler with the CCD, however instructions for
performing this task in either mode are provided.
IN MONOCHROMATOR MODE
1. Select a light source with a known sharp line and connect it to the monochromator
2. Set the slits to as narrow as possible while still obtaining a decent signal
3. Scan across the line.
4. On the exit slit arm, loosen the set screw that fastens the collar into place
Figure 10: Exit slit focusing collar and fastening set-screw
5. Rotate the collar counter-clockwise from the top and then push the slit down until
the two collars make contact. Do this far enough to go beyond the suspected focal
distance
6. Take a spectral scan of the selected line
7. Note whether or not the line has become any narrower and the signal has
increased. If it has, continue to lower the slit.
8. If it appears that the signal has come out of focus, rotate the collar in the opposite
direction a set amount and take another scan
9. Continue to repeat step 8 until you have scanned past the focal point and the line
begins to broaden and have a lower peak signal.
10. Begin rotating the collar in smaller increments in the opposite direction and
scanning at each interval until again you have just passed the focal position.
11. Repeat step 10, with smaller adjustment changes each time you change directions,
until you are finally confident to have settled at the focal point.
12. Retighten the set screw to ensure the focus is held.

IN SPECTROMETER MODE
1. Select a light source with a known sharp line and connect it to the monochromator
2. Set the slits to as narrow as possible while still obtaining a decent signal
3. Scan so that the line is centered in the CCD
4. On the CCD arm, loosen the set screw that fastens the collar into place
Figure 11: CCD focusing collar and fastening set-screw
5. Rotate the collar counter-clockwise from the top and then push the slit down until
the two collars make contact. Do this far enough to go beyond the suspected focal
distance
6. Note whether or not the line has become any narrower and the signal has
increased. If it has, continue to lower the slit.
7. If it appears that the signal has come out of focus, rotate the collar in the opposite
direction a set amount and continue until you have gone beyond the focal point
and the line begins to broaden and have a lower peak signal.
8. Begin rotating the collar in smaller increments in the opposite direction and
monitoring the line at each interval until again you have just passed the focal
position.
9. Repeat step 10, with smaller adjustment changes each time you change directions,
until you are finally confident to have settled at the focal point.
10. Retighten the set screw to ensure the focus is held.

ADD-ON OPTIONS
Adjustable Slit Assemlies
Motorized Scanning
Software Control
Adaptor Flange for Purged Operation
RF Light Source
Pumping Station
CCD Array
EUV/VUV/UV/Vis detector

APPENDIX:
SYSTEM COMPONENTS
MONOCHROMATOR
The VM200 monochromator (Vacuum Monochromator 200mm focal length) contains a
concave holographic grating with AlMgF2 coating. This grating has the following
specifications:
Model #: VM200
Serial #: 615
No. of lines/mm: 1200 l/mm
Diameter: 40 x 45mm
Coating: AlMgF2
Spectral range of operation: 100 –400 nm
Radius of curvature: 200mm
Body Seal Types: Viton O-rings
Body Mating Flanges: 2 ¾” Conflat type x 2
Ultimate Pressure: < 1x10-6 mbar
Wavelength drive:
Type: 10 turn dial / lead screw
Backlash: 0.5 nm (vacuum)
Step size: 0.4 –15 Angstroms
Standard Scanning Speeds: 0.4 –15 nm/sec
Accuracy: ±0.3 nm
Figure 12: Grating efficiency curve

PHOTODIODE DETECTOR
The XUVSi-D-L-EUV contains an absolute UV silicon photodiode with a low noise,
high gain amplifier.
Type: Absolute UV Silicon Photodiode
Photodiode Model #: AXUV100G
Photodiode Sensitivity Range: 1 nm - 1000 nm
Photodiode Size: 10 x 10 mm
Internal Gain: 1 x 109A/V
A to D Type: LabJack
A to D Bit Resolution: 12 Bit
Differential gains: 1, 2, 4, 5, 8, 10, 20
Figure 13: Typical response curve of the AXUV photodiode (go to http://www.ird-
inc.com/text/axuvopeprin.txt for complete date table)
CCD
Resonance Ltd. uses a Hamamatsu CCD array modified to allow detection of EUV/VUV
radiation.
Type: Linear CCD, 2048 elements
Height/Width of Active Area: 0.2 x 28 mm
Model: S9840 (Hamamatsu)
Number of Active Pixels: 2048
Pixel size: 14 um x 14 um

Figure 14: Typical response curve of the Hamamatsu S9840 CCD
ADJUSTABLE SLITS
Resonance Ltd. uses ThorLabs Adjustable slits modified to be compatible with vacuum
operations.
Slit Height: 1 mm
Slit Width Range: 0 –6 mm
Blade Parallelism: < 25 µm
Slit Width Accuracy: ± 50 µm

NIST Calibration
Figure 15: NIST Standard Calibration Curve
UV Diode NIST Calibration
0
0.2
0.4
0.6
0.8
1
1.2
100 150 200 250 300 350 400
Wavelength (nm)
Signal (V)
NIST Standard
Customer Diode
Figure 16: NIST Calibration Measurements

NIST Traceable Calibration
NIST Transfer standard diode 02-126 with <3% QE annual drift as of 2005
0
0.2
0.4
0.6
0.8
1
1.2
1.4
115 135 155 175 195 215 235 255
Wavelength (nm)
Signal (V)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Quantum Efficiency (electron/photon)
NIST Transfer Standard Signal
Customer Diode Signal
Standard QE Curve
Customer Diode QE
Figure 17: NIST Traceable Quantum Efficiency Chart