Newport Cornerstone 130B User Manual
90088262 MCS130B, Rev B
s
1/8m Monochromator Family
User's Manual
Cornerstone
™
130B
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
2
TABLE OF CONTENTS
1 GENERAL INFORMATION .................................................................................................. 5
1.1 SYMBOLS AND DEFINITIONS ................................................................................ 6
1.2 GENERAL WARNINGS .......................................................................................... 7
1.3 ELECTRICAL HAZARDS ........................................................................................ 7
1.4 MECHANICAL HANDLING ................................ ...................................................... 8
1.5 OPTICS CARE AND HANDLING.............................................................................. 8
2 INTRODUCTION................................................................................................ ................ 9
2.1 OPTICAL CONFIGURATION ................................................................ ................... 9
2.2 STRAY LIGHT REJECTION ...................................................................................10
2.3 AVAILABLE MODELS ...........................................................................................10
2.4 TYPICAL APPLICATIONS......................................................................................11
3 INITIAL SETUP.................................................................................................................12
3.1 WHAT’S INCLUDED..............................................................................................12
3.2 UNPACKING ................................................................ ........................................12
3.3 CHOOSING A LOCATION......................................................................................12
3.4 MOUNTING OPTIONS ..........................................................................................13
3.5 ELECTRICAL AND COMPUTER CONNECTIONS .....................................................14
4 SHUTTER ................................................................................................ ........................16
5 INPUT AND OUTPUT SLITS...............................................................................................17
5.1 FIXED SLITS........................................................................................................17
5.2 MICROMETER ADJUSTABLE SLITS ......................................................................18
6 DIFFRACTION GRATINGS ................................................................................................20
6.1 GRATING TYPES .................................................................................................21
6.2 GRATING EFFICIENCY AND BLAZING ...................................................................22
6.3 POLARIZATION EFFECTS ....................................................................................24
7 MONOCHROMATOR RESOLUTION ................................................................................... 25
7.1 DETERMINING RESOLUTION ...............................................................................26
8 GETTING LIGHT INTO A MONOCHROMATOR ....................................................................28
8.1 ACCEPTANCE PYRAMID ......................................................................................28
8.2 F NUMBER MATCHING.........................................................................................29
9 BLOCKING HIGHER ORDER RADIATION ...........................................................................30
9.1 ORDER SORTING FILTERS ..................................................................................30
10 COMMUNICATION METHODS ...........................................................................................31
10.1 UTILITY SOFTWARE ............................................................................................33
10.2 HAND CONTROLLER ...........................................................................................34
10.3 TRACQ BASIC SOFTWARE...................................................................................35
10.4 LOW-LEVEL COMMANDS .....................................................................................35
11 GRATING INSTALLATION AND CALIBRATION ....................................................................36
11.1 RECALIBRATION SERVICES................................................................ .................36
11.2 SETTING THE WAVELENGTH OFFSET ................................................................ ..36
11.3 DETERMINING THE GRATING CALIBRATION FACTOR ...........................................37
11.4 ALTERNATIVE METHOD (CS130B only) .................................................................37
11.5 GRATING INSTALLATION ................................ .....................................................38
12 TROUBLESHOOTING ................................................................................................ .......40
12.1 CORRUPTED MEMORY........................................................................................40
13 SPECIFICATIONS.............................................................................................................41
14 DIMENSIONS ................................................................ ...................................................42
15 APPENDIX I: LOW LEVEL (REMOTE) COMMANDS AND QUERIES .......................................45
15.1 OPENING RS-232 COMMUNICATION INTERFACE ..................................................65
15.2 COMMAND AND QUERY SYNTAX .........................................................................65
15.3 STANDARD MODE ...............................................................................................65
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
3
15.4 HANDSHAKE MODE.............................................................................................65
15.5 CS130B COMMAND REFERENCE SUMMARY ........................................................65
15.6 DETAILED COMMAND REFERENCE......................................................................65
15.7 ERROR CODES ...................................................................................................65
16 APPENDIX II: HAND CONTROLLER COMMANDS ...............................................................65
16.1 ACTIVATING THE HAND CONTROLLER.................................................................65
16.2 USING THE KEYPAD ................................................................ ............................65
16.3 KEY REFERENCE ................................................................................................66
17 APPENDIX IV: GRATING PHYSICS TUTORIAL ...................................................................68
17.1 THE GRATING EQUATION ....................................................................................68
17.2 THE GRATING EQUATION IN PRACTICE ...............................................................69
17.3 GRATING ORDER ................................................................................................70
17.4 GRATING DISPERSION ................................ ........................................................71
17.5 GRATING ILLUMINATION AND RESOLUTION.........................................................71
18 WARRANTY AND SERVICE...............................................................................................72
18.1 CONTACTING NEWPORT CORPORATION.............................................................72
18.2 REQUEST FOR ASSISTANCE / SERVICE ............................................................... 73
18.3 REPAIR SERVICE ................................................................ ................................73
18.4 NON-WARRANTY REPAIR ................................................................ ....................73
18.5 WARRANTY REPAIR ............................................................................................ 74
18.6 LOANER / DEMO MATERIAL ................................................................................. 75
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
4
LIST OF FIGURES
Figure 1: Optical Configuration of the Cornerstone 130B ................................ ................................. 9
Figure 2: Model Number Codes................................................................................................ ..10
Figure 3: Tunable Monochromatic Light Source ................................ ............................................11
Figure 4: Monochromator with Lock-In Digital Amplifier ..................................................................11
Figure 5: Model 74017 Mounting Kit............................................................................................13
Figure 6: Monochromator Connections ........................................................................................15
Figure 7: A Fixed Slit Installed into the Holder...............................................................................17
Figure 8: Available Fixed Slits Table ...........................................................................................17
Figure 9: A Micrometer Adjustable Slit ......................................................................................... 18
Figure 10: A Fully Closed Micrometer Adjustable Slit .....................................................................18
Figure 11: Shortest Micrometer Adjustable Slit Height....................................................................19
Figure 12: Tallest Micrometer Adjustable Slit Height ......................................................................19
Figure 13: Grating Installed onto Mount .......................................................................................20
Figure 14: Grating Properties Table ............................................................................................21
Figure 15: Grating Efficiency Curves for CS130B Monochromator Pre-Configured Models ..................23
Figure 16: Resolution vs. Throughput ................................................................ ..........................25
Figure 17: Some of the Fixed Slit Sizes Available..........................................................................27
Figure 18: Acceptance Pyramid of Monochromator .......................................................................28
Figure 19: Grating Correctly “Filled” with Light ..............................................................................28
Figure 20: Mismatched F Numbers Resulting in Stray Light ............................................................ 29
Figure 21: F Number Matcher Used with Fiber Optic Cable ............................................................29
Figure 22: Model USFW-100 Filter Wheel ....................................................................................31
Figure 23: Model 74010 Filter Wheel...........................................................................................32
Figure 24: Mono Utility Software Screens ....................................................................................33
Figure 25: Cornerstone 130B Monochromator with 74009 Hand Controller .......................................34
Figure 26: TracQ Basic Screens .................................................................................................35
Figure 27: Grating Platform without Gratings ................................................................................39
Figure 28: Grating Platform with Gratings Installed ........................................................................39
Figure 29: Entering Calibration Values in Utility Software ...............................................................40
Figure 30: Cornerstone 130B Dimensions ....................................................................................42
Figure 31: 74001 Micrometer Adjustable Slit Dimensions ...............................................................43
Figure 32: 77294 Fixed Slit Dimensions.......................................................................................43
Figure 33: Model 74006 Mounting Plate.......................................................................................44
Figure 34: 74009 Hand Controller Keypad ...................................................................................65
Figure 35: The Sawtooth Pattern of a Grating Section....................................................................68
Figure 36: The Grating Equation Satisfied for a Parallel Beam of Monochromatic Light .......................69
Figure 37: Polychromatic Light Diffracted From a Grating ...............................................................69
Figure 38: Sign Convention for the Angle of Incidence, Angle of Diffraction and Grating Angle .............70
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
5
1 0BGENERAL INFORMATION
Thank you for your purchase of this Cornerstone™ 130B Monochromator from Newport-Oriel
Instruments®.
Please carefully read the following important safety precautions prior to unpacking and operating this
equipment. In addition, please refer to the complete User’s Manual and all other documentation provided
for additional important notes and cautionary statements regarding the use and operation of the system.
Do not attempt to operate any system without reading all the information provided with each of the
components.
Please read all instructions that were provided prior to operation of the system. If
there are any questions, please contact Newport Corp. or the representative
through whom the system was purchased.
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
6
1.1 18BSYMBOLS AND DEFINITIONS
WARNING
Situation has the potential to cause bodily harm or death.
CAUTION
Situation has the potential to cause damage to property or equipment.
ELECTRICAL SHOCK
Hazard arising from dangerous voltage. Any mishandling could result
in irreparable damage to the equipment, and personal injury or death.
EUROPEAN UNION CE MARK
The presence of the CE Mark on Newport Corporation equipment
means that it has been designed, tested and certified as complying
with all applicable European Union (CE) regulations and
recommendations.
WEEE
This symbol on the product or on its packaging indicates that this
product must not be disposed of with regular waste. Instead, it is the
user’s responsibility to dispose of waste equipment according t o the
local laws. The separate collection and recycling of the waste
equipment at the time of disposal will help to conserve natural
resources and ensure that the materials are recycled in a manner that
protects human health and the environment.
ON
The ON symbol in the above figure indicates the ON position of the
power switch.
OFF
The OFF symbol in the above figure indicates the OFF position of the
power switch.
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
7
1.2 19BGENERAL WARNINGS
• Read all warnings and operating instructions for this system prior to setup and use.
• Do not use this equipment in or near water.
• To prevent damage to the equipment, read the instructions in the equipment manual for proper
input voltage and check the requirement on the power supply.
• This equipment is grounded through the grounding conductor of the power cord.
• Route power cords and other cables so they are not likely to be damaged.
• Disconnect power before cleaning the equipment
• Do not use liquid or aerosol cleaners; use only a damp lint-free cloth.
• Lock out all electrical power sources before servicing the equipment.
• To avoid explosion, do not operate this equipment in an explosive atmosphere.
• Qualified service personnel should perform safety checks after any service.
• If this equipment is used in a manner not specified in this manual, the protection provided by this
equipment may be impaired.
• Do not position this product in such a manner that would make it difficult to disconnect the power
cords.
• Use only the specified replacement parts.
• Follow precautions for static sensitive devices when handling this equipment.
• This product should only be powered as described in the manual.
• Do not remove the cover for normal usage.
1.3 20BELECTRICAL HAZARDS
Make all connections to or from the instrument with the power off.
The Cornerstone B requires DC voltage for operation, which is provided by an external power
supply. This power supply has no user serviceable parts. Do not attempt to open the external
power supply. Do not attempt to work in the Cornerstone B compartment without first
disconnecting the power cord, since electrical hazards are present inside the compartment even
with the power switch in the “off” position.
The Cornerstone B monochromator contains a microprocessor and should be installed with
appropriate surge/EMI/RFI protection on the power line. A dedicated power line or line isolation
may be required for some extremely noisy sites. The electronic circuits within the monochromator
are extremely sensitive to static electricity and radiated electromagnetic fields. Operation of this
instrument close to intense pulsed sources (lasers, xenon strobes, arc lamps, etc.) may
compromise performance if shielding is inadequate, and may cause permanent damage to the
microprocessor.
Note: This instrument conforms to CE standards for both safety and EMC. During normal use, this
equipment will not pose any electrical hazards to the user. Read all warnings before installing or
operating this system. If there are any questions or concerns, contact Oriel Instruments or the
regional sales representative for Newport.
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
8
1.4 21BMECHANICAL HANDLING
Avoid dropping, sudden shocks, or rough handling of the monochromator since this may cause the
system to go out of calibration and may destroy the high precision drive components or optics.
1.5 22BOPTICS CARE AND HANDLING
Do not touch any optical surfaces since this is likely to cause irreparable damage. Always wear
powder-free gloves to cover the entire hand, not finger cots. Never touch the surface of a
diffraction grating, even when wearing gloves.
Dust or debris on the grating surface may negatively affect performance, so it should be prevented
from entering the instrument by keeping the protective grating covers in place when it is not in use.
If the gratings do require cleaning, do not attempt to clean any optical surface except by blowing
off dust or lint particles with a stream of dry clean air or nitrogen. Wiping the grating surface will
cause permanent damage.
Avoid getting any moisture or condensation onto the grating. Do not breathe on or talk directly in
front of a grating, as the moisture from one’s breath should never be allowed to condens e on t he
grating surface.
This instrument comes with gratings pre-installed, aligned, and the calibration parameters set. An
experienced user may choose to install a different grating in the field, although it is strongly
encouraged to send the instrument back to the factory instead.
If a grating is installed in the field, the grating cover must never touch the grating’s front surfac e.
The specially designed grating cover contacts only the edges of the grating. When removing this
cover, a grating can be scratched easily, so use extreme caution when handling.
Hand tighten the grating mount screws. Do not use tools, since this may cause damage to the
drive assembly. Never touch the surface of the grating, even while wearing gloves. Handle the
grating assembly only by its mount.
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
9
2 1BINTRODUCTION
In developing the Cornerstone 130B monochromator, Newport-Oriel Instruments leveraged their
extensive experience to design a compact, inexpensive instrument that has all the versatility required by
researchers. The ease of automated control and small size also make this an ideal monochromator for
many OEM applications.
Each of these instruments includes two diffraction gratings, filter wheel control circuitry, and an integrated
electronic shutter. Communication may be established using USB, RS232, or an optional hand controller
designed specifically for use with the Cornerstone family of monochromators. In addition, this instrument
can be purged with dry nitrogen for work below the oxygen absorption cut-on at 180 nm.
The Cornerstone 130B includes a utility program designed to run on a computer using the Microsoft
Windows operating system. The simple, intuitive interface means that users can get up and running
within minutes of opening the box. Instrument control examples using National Instruments LabVIEW are
provided, along with a command set and API for those wishing to develop their own programs. An
optional hand controller may be used for quick access to all common commands and queries, without
requiring a computer. This is especially beneficial in universities and secure facilities.
A wide selection of grating models is available for the Cornerstone 130B, as well as special order options.
Throughput and resolution can be adjusted by selecting the appropriate slit size. Fixed slits are available
for high accuracy and repeatability, and micrometer adjustable slits may be used for maximum flexibility.
2.1 23BOPTICAL CONFIGURATION
The optical design of the Cornerstone 130B is based on an out-of-plane version of an Ebert-Fastie
monochromator. The input and output ports are in line with each other, simplifying system
alignment. The optical configuration is designed to ensure high resolution and maximum
throughput. This F/3.9 monochromator is optimized to provide excellent stray light rejection while
minimizing aberrations. A high precision motor is used to select the desired wavelength and switch
between diffraction gratings quickly, without sacrificing performance.
Figure 1: Optical Configuration of the Cornerstone 130B
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
10
2.2 24BSTRAY LIGHT REJECTION
Stray light may have a variety of origins. Its presence may be caused by a wide variety of design
and manufacturing factors. The level of stray light due to the dispersed radiation inside the
monochromator is affected by the design of the instrument, its baffles, and interior finish. The
Cornerstone 130B incorporates a sophisticated design, proven materials, and a quality
manufacturing system to ensure high stray light rejection.
The amount of stray light measured on top of true signal will depend on many experimental factors
as well as the performance of the instrument. When comparing stray light specifications, it is
important to compare values that were measured under identical circumstances. The spectral
distribution of the source and the response of the detection system are often the dominant factors
when determining a stray light value.
2.3 25BAVAILABLE MODELS
The model number of each Cornerstone monochromator reflects its features. Refer to the part
number code to determine the features present in the instrument. If the model number differs from
the code, it is a Special Order configuration. In that case, refer to the Sales Order for the
instrument for more information.
Figure 2: Model Number Codes
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
11
2.4 26BTYPICAL APPLICATIONS
The applications for the Cornerstone 130B monochromator are practically limitless. Here we
present two examples: a tunable monochromatic light source and an optically chopped light
source used with a lock-in digital amplifier to extract small signal levels from background radiation.
All components shown are available from Newport.
Figure 3: Tunable Monochromatic Light Source
Figure 4: Monochromator with Lock-In Digital Amplifier
Interconnect
Power Adapter
with Power Cord
USB Cable to
Computer
Collimating
Lens
Cornerstone
130B
Monochromator
Power Cord
Collimating
and
Focus Optics
Light Source
Motorized
Filter
Wheel
Tunable monochromatic light
source on mounting plate
Monochromatic
Light Output
Arc Lamp
Power Supply
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
12
3 2BINITIAL SETUP
3.1 27BWHAT’S INCLUDED
• Two diffraction gratings, installed and aligned
• Electronic shutter at input port
• A choice of micrometer adjustable slits or fixed slit holders at the input and output ports
• Electronics interface for RS232 or USB communication
• An MPT plug to accept a hose barb to purge the instrument compartment for measurements
below 180 nm (actual capability is grating configuration dependent)
• LabVIEW™ based utility software
• Application Programming Interface (API) for LabVIEW™ with examples
• Certificate of Calibration
• Monochromator Power Supply
• Line cords based on geographic location
• User’s manual
3.2 28BUNPACKING
Remove all items from the shipping containers and verify each item is accounted for. The
instrument is carefully packaged to minimize the possibility of damage during shipment. Inspect
the shipping box for external signs of damage or mishandling. Inspect the contents for damage.
If any item is missing or damaged, immediately contact Newport or the representative from whom
the system was purchased.
It is suggested to save the packaging material and shipping container, in case the equipment
needs to be relocated at a future date.
WARNING
Do not attempt to operate this equipment if there is evidence of
shipping damage or there is suspicion that the equipment will not
operate correctly. Damaged equipment may present hazards.
3.3 29BCHOOSING A LOCATION
Choose an installation location where the power requirements can be met for the monochromator,
as well as the rest of the optical system. Be sure power is not applied to the system until the setup
has been completed and all electrical connections made.
Ensure that there is easy access to the monochromator’s power switch and the electrical outlet.
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
13
3.4 30BMOUNTING OPTIONS
The ability to mount the monochromator simplifies setup and alignment of the optical system. The
mounting plates or kits also help ensure consistent results over time, as the monochromator
cannot be accidentally moved out of position. The following options are available for securing the
Cornerstone 130B:
• Mounting plate
• Mounting kit to couple with Oriel’s Research Lamp Housings
• Optical rods
The 74006 Mounting Plate is used to secure a Cornerstone 130B Monochromator to an inch or
metric optical table. The plate adds 0.25 inch [6.35 mm] to the optical height. If the Cornerstone
130B will be used with Oriel’s research lamp housing, consider using the 74017 mounting kit.
The 74017 Mounting Kit connects the Cornerstone 130B monochromator to an arc lamp or quartz
tungsten halogen light source. This kit is compatible with Oriel's Research Lamp Housings, which
hold 50 to 250 watt lamps. It includes a base plate, a flexible light shield, a 1.5-inch diameter
focusing lens and lens holder. All the hardware required to mount the lamp housing and
monochromator to the base plate is provided. The mounting kit's base plate comes with four
adjustable leveling feet. The feet may be removed to secure the base plate to an inch or metric
optical table.
The most economical option is to use optical rods and rod holders to mount the Cornerstone 130B
to an optical table or breadboard. On the monochromator’s mounting surface, four #1/4-20
threaded holes may be used to install standard optical rods. Care should be taken to ensure the
instrument is level and secured well enough that its location remains consistent over time, even if
the instrument is bumped or components coupled to the ports.
Figure 5: Model 74017 Mounting Kit
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
14
3.5 31BELECTRICAL AND COMPUTER CONNECTIONS
Before powering up the system for the first time, it is suggested to have a qualified electrician
verify the wall socket to be used with the instrument meets the requirements for operation as
noted.
Before making any electrical connections, verify the front panel power switch is in the off position
for the monochromator.
WARNING
To avoid electric shock, connect the instrument to properly earthgrounded, 3-prong receptacles only. Failure to observe this
precaution can result in severe injury or death.
The line voltage requirement is as follows:
Monochromator Power Adapter 100 to 240 VAC, 47-63 Hz
The monochromator conforms to CE standards for both safety and EMC. During normal use, this
equipment will not pose any electrical hazards to the user. Read all warnings before installing or
operating this system. If there are any questions or concerns, contact Oriel Instruments or the
regional sales representative for Newport.
ELECTRICAL SHOCK
Never attempt to open the lamp power supply or monochromator
power adapter. These items do not contain any user serviceable
parts. Failure to follow this warning can result in severe injury or
death.
The monochromator’s power adapter connects to an AC wall socket and supplies DC volt age to
the instrument. Do not open the monochromator cover and attempt to work inside without first
turning the instrument off and disconnecting the power cord from the AC mains.
The ribbon cable connecting the monochromator to the optional filter wheel is installed before
the system ships out. The monochromator provides power to the filter wheel and allows the user
to select which filter is placed in the optical path.
Ensure the monochromator power switch is in the off position (marked as O). Then connect the
power adapter to the monochromator, as shown. Insert the power cord provided into the power
adapter and connect to the AC mains.
Connect the USB or RS232 cable to the monochromator. Plug the other end of the cable into the
computer only after any software controlling the monochromator has been installed.
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
15
Figure 6: Monochromator Connections
A USB cable (model 70044) and RS232 cable (model 70040) are included with each Cornerstone
130B.
If using a commercially available USB/GPIB or USB/RS232 converter cable, the driver for this cable
must be installed before communication to the monochromator can be established.
Follow the instructions provided in the Quick Start Guide to install the utility software onto a
computer.
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
16
4 3BSHUTTER
An electronic shutter is integrated into the Cornerstone B monochromator’s design. It is mounte d i n s ide
the housing at the input port. This shutter is normally closed.
The shutter is used to close the light path when output light is not required. This allows the light source to
remain on, and therefore remain warmed up, so that it continues to provide stable performance.
Additionally, restarting a lamp results in wear of the filament (with quartz tungsten halogen lamps) or wear
of the anode/cathode (with arc lamps). Therefore, when the light is not needed during short periods,
closing the shutter is suggested.
Diffraction gratings are mounted on a precision rotation stage inside the monochromator. When the
monochromator switches between diffraction gratings, the changing angle of the grating causes light to
be diffracted at various wavelengths. This includes white light, which is output at a higher power than
other individual wavelengths. In order to prevent saturation of a detection system, it is suggested to close
the shutter temporarily while changing gratings. It is especially important to prevent saturation and
possible damage when using a photomultiplier tube.
A scan may be completed while the shutter is closed to perform background subtraction calculations on
subsequent scans completed while the shutter is open.
Please note that the shutter is not designed to block high power direct light. When using a 450W or
greater light source, heat mitigation strategies should be employed. For example, Oriel offers liquid filters
to protect the shutter, filters, and other items to prevent potential heat damage.
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
17
5 4BINPUT AND OUTPUT SLITS
To operate any monochromator, slits are required at the input and output port. The slit assemblies
offered with the Cornerstone 130B all have 1.5-inch male flanges, allowing them to be easily connected to
the wide variety of Oriel accessories and instruments.
Note: The slits need to be the same width and height at the input and output ports. A wider input slit
when compared to the output slit results in more stray light inside the instrument. A wider output slit with
respect to the input slit will not increase throughput.
5.1 32BFIXED SLITS
The fixed slits slide into the 77294 holders at the input and output port. The width and height
cannot be adjusted, but may be individually replaced with other slit sizes. Fixed slits are a low cost
alternative to micrometer adjustable slits, and provide excellent repeatability. They are a good
choice when only a few slit sizes are required.
Fixed slits are sold separately to allow customized choices based on the needs of the application.
When ordering, be sure to purchase two fixed slits of the same model – one for the input port, and
the other for the output port. Insert the slit as shown, with the label facing outward. Be sure that it
is fully inserted into the holder’s slot to ensure the best performance and repeatability.
Figure 7: A Fixed Slit Installed into the Holder
Fixed Slit Model
Width
Height
77222
10 µm
2 mm
77221
50 µm
3 mm
77220
25 µm
3 mm
77219
50 µm
6 mm
77218
120 µm
18 mm*
77217
280 µm
18 mm*
77216
600 µm
18 mm*
77215
760 µm
18 mm*
77214
1.24 mm
18 mm*
77213
1.56 mm
18 mm*
77212
3.16 mm
18 mm*
77211
6.32 mm
18 mm*
*Actual slit height is 18 mm, usable height is 12 mm.
Figure 8: Available Fixed Slits Table
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
18
5.2 33BMICROMETER ADJUSTABLE SLITS
Micrometer adjustable slit assemblies are continuously variable from fully closed (4 µm) to 3 mm
width. A height adjustment slide allows variation in the height from 3 to 12 mm. Benefits of the
micrometer adjustable slits are flexibility and high throughput. This type of slit is designed primarily
for versatility and convenience in changing resolution and throughput, which are related to the slit
width.
Figure 9: A Micrometer Adjustable Slit
The slit width setting is read on the micrometer. A set of numbers go around the turning dial.
Another set of numbers are located on the shaft. When the zeroes in both these locations line up,
the slit is fully closed. Turning the dial clockwise advances the dial position further down on the
shaft, closer to the body of the micrometer. This opens the slit.
Use a 10x multiplier to convert the micrometer reading to the actual slit opening size. For
example, turning the dial one full revolution starting from the fully closed position will give a
reading of 50 on the micrometer. Using the multiplier, this indicates the micrometer width is set to
500 um. If unsure of the reading, begin at the fully closed position and add up each full revolution
made.
Figure 10: A Fully Closed Micrometer Adjustable Slit
The micrometer is used to make the slit
narrow or wide
The slide is used to
change the slit height
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
19
The slit height is continuously adjustable. Pull the lever out for the shortest height. Push the slide
in for the tallest height setting.
Figure 11: Shortest Micrometer Adjustable Slit Height
Figure 12: Tallest Micrometer Adjustable Slit Height
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
20
6 5BDIFFRACTION GRATINGS
Diffraction gratings are used to disperse light; that is to spatially separate light of different wavelengths.
They have replaced prisms in most fields of spectral analysis. Two gratings are installed into the
Cornerstone 130B monochromator. In general, the grating with the highest efficiency is chosen at a
particular wavelength. The optional TracQ™ Basic Data Acquisition and Radiometery Software allows
users to set up a specific grating switchover wavelength, so the most appropriate grating will
automatically be chosen while performing a scan over a range of wavelengths.
The Cornerstone 130B monochromators feature diffraction gratings produced by Richardson Gratings.
Both Oriel Instruments and Richardson Gratings are part of Newport, and have a long history of working
together to design monochromators that are appropriate for a wide variety of applications.
A tutorial on grating physics may be found in the Appendix of this user’s manual.
The photo below illustrates a diffraction grating mounted into a holder for installation into the Cornerstone
130B monochromator. An unmounted grating cannot be installed by the user in the field; gratings must
be installed onto the appropriate mount for the Cornerstone 130B monochromator and aligned at the
factory.
Figure 13: Grating Installed onto Mount
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
21
6.1 34BGRATING TYPES
Ruled grating masters are produced using a ruling engine with an extremely fine cutting tool.
Holographic gratings (also called interference gratings) are produced by recording interference
fringes in photoresist. The different techniques cause some differences in performance.
Holographic gratings are most frequently available at high groove densities due to manufacturing
limitations inherent in the technology. They are generally favored for work in the UV and through
the visible to about 600 nm. Holographic gratings produce less scattering, thereby reducing stray
light inside the monochromator.
Ruled gratings typically have higher efficiencies. They may have periodic errors in the grating
grooves caused by minor defects in the ruling machine, resulting in anomalous readings or
“ghosts”. Holographic gratings do not suffer from ghosts, so interpretation of line spectra is
simplified.
The signal-to-noise ratio (SNR) is the ratio of diffracted energy to unwanted light energy. Although it
may be assumed that increasing diffraction efficiency will increase SNR, stray light usually plays the
limiting role in the achievable SNR for a grating system. Note that the actual signal to noise ratio will
depend on the spectral content of the incident light and the detector.
Figure 14: Grating Properties Table
GRATING PROPERTIES
Configuration
Grating
Position
Type
Groove
Density
(lines/mm)
Blaze
Wavelength
(nm)
Reciprocal
Dispersion
(nm/mm)
High
Resolution
#1
Ruled
2400
240
2.7
#2
Ruled
1200
500
5.3
Holographic
#1
Holographic
1200
250
5.5
#2
Holographic
1800
500
3.3
Extended
Range
#1
Ruled
600
400
11
#2
Ruled
600
1000
10.6
Near IR
#1
Ruled
600
1000
10.6
#2
Ruled
300
2000
21.2
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
22
6.2 35BGRATING EFFICIENCY AND BLAZING
Efficiency and its variation with wavelength and spectral order are important characteristics of a
diffraction grating. For a reflection grating, efficiency is defined as the energy flow (power) of
monochromatic light diffracted into the order being measured, relative either to the energy flow of
the incident light (absolute efficiency) or to the energy flow of specular reflection from a polished
mirror substrate coated with the same material (relative efficiency). Efficiency is defined similarly for
transmission gratings, except that an uncoated substrate is used in the measurement of relative
efficiency.
High-efficiency gratings are desirable for several reasons. A grating with high efficiency is more
useful than one with lower efficiency in measuring weak transition lines in optical spectra. A grating
with high efficiency may allow the reflectivity and transmissivity specifications for the other
components in the spectrometer to be relaxed. Moreover, higher diffracted energy may imply lower
instrumental stray light due to other diffracted orders, as the total energy flow for a given
wavelength leaving the grating is conserved (being equal to the energy flow incident on it minus any
scattering and absorption).
Control over the magnitude and variation of diffracted energy with wavelength is called blazing, and
it involves the manipulation of the micro-geometry of the grating grooves. The energy flow
distribution (by wavelength) of a diffraction grating can be altered by modifying the shape of the
grating grooves. The blaze wavelength is the wavelength where the grating efficiency is enhanced
by shaping the grating grooves. Although holographic gratings are not shaped like ruled gratings,
the peak grating efficiency wavelength is also referred to as the blaze wavelength.
The choice of an optimal efficiency curve for a grating depends on the specific application. Often
the desired instrumental efficiency is linear; that is, the intensity of light transformed into signal at
the image plane must be constant across the spectrum. To approach this as closely as possible,
the spectral emissivity of the light source and the spectral response of the detector should be
considered, from which the desired grating efficiency curve can be derived. Usually this requires
peak grating efficiency in the region of the spectrum where the detectors are least sensitive.
In many instances, the diffracted power depends on the polarization of the incident light. For
completely unpolarized incident light, the efficiency curve will be exactly halfway between the P and
S efficiency curves. Anomalies are locations on an efficiency curve (efficiency plotted vs.
wavelength) at which the efficiency changes abruptly. These sharp peaks and troughs in an
efficiency curve are sometimes referred to as Wood's anomalies.
The efficiency curves shown are relative (not absolute) and were measured using an in-plane near
Littrow configuration. Please use the curves as a guide and not as absolute data. Grating
diffraction is dependent on the polarization of the radiation incident on the grating.
Software such as the Mono Utility and TracQ Basic may be configured to switch between gratings
at a specific wavelength. Typically, the most efficient grating is selected, so this switchover
wavelength would be where the two efficiency curves meet. To determine empirically the ideal
switchover wavelength, the output should be measured by an optical detector. Run a scan in the
crossover region using only Grating 1. Repeat the scan using only Grating 2. Where the detector
readings are closest is the optimal switchover wavelength.
If the selected grating’s efficiency has a sudden increase or decrease at a particularly critical
wavelength and the application demands extreme accuracy, it may be more desirable to select the
grating with the more gradual change in efficiency.
90088262 MCS130B
CORNERSTONE 130B MONOCHROMATORS
23
Figure 15: Grating Efficiency Curves for CS130B Monochromator Pre-Configured Models
High Resolution Configuration
Holographic Grating Configuration
Extended Range Configuration
Near Infrared Configuration
Loading...