Oriel Cornerstone™ 130 1/8 m Monochromator
Oriel Cornerstone™ 130 1/8 m Monochromator
  • New, USB 2.0 models; RS-232 and IEEE-488 also available
  • Excellent stray light control
  • Motorized wavelength drive
  • Operates two gratings simultaneously, individually replaceable
  • Electronic shutter
DescriptionSpecifications Models Literature
Cornerstone 130 1/8 m Monochromator

Optical Configuration

The optical design of these instruments is based on an out of plane version of the Ebert-Fastie monochromator. This is a 180°, in-line configuration, which simplifies system alignment. Additionally, this compact design has a very small footprint so it requires little tabletop space. For the Cornerstone 130, we computer optimized this optical configuration to ensure the highest resolution, greatest throughput, and the lowest stray light. Although the system is a fast F/3.7, the optimized design provides excellent stray light rejection while minimizing aberrations.


Fig. 1 Optical configuration of the CornerstoneTM 130 Monochromators

Motorized Wavelength Drive

The CornerstoneTM 130 is our only automated 1/8 m monochromator. Your computer controls everything. The wavelength drive in this monochromator was designed to increase speed as much as possible without sacrificing accuracy or precision. This rapid direct drive mechanism slews at a maximum rate of 205 nm/s (with 1200 l/mm grating). Wavelength accuracy with a 1200 l/mm grating is 0.50 nm and precision is a tight 0.11 nm. Cornerstone 130 also uses the wavelength drive to change gratings; the rapid slew rate of the instrument’s drive allows grating changes in only ~10 seconds.

Stray Light

Stray light comes in a number of different forms and may be caused by a wide variety of design and manufacturing factors. The Cornerstone™ 130 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. Here we list two stray light tests to provide some meaningful points of comparison. Both measurements used a UV-VIS photomultiplier, Oriel model 77340. The first test also used an Oriel deuterium source.

Measurement 1*

Using a holographic grating, blazed at 250 nm, the signal at 210 nm with a glass plate in the beam path was 0.1% of the signal at 210 nm without the glass. At 250 nm, the stray light signal was only 0.025% of the unblocked signal.

Measurement 2**

Using a Helium Neon Laser at 632.8 nm focused on the slit in an F/4 cone, the average of the stray radiation readings at 612.8 and 652.8 nm was 0.008% of the signal at 632.8 nm. A 1200 l/mm, 500 nm blaze ruled grating was used. In this case, the response of the detector is irrelevant as the only light detected is at 632.8 nm.
* The comparison is based on a taxing, but real measurement scenario, measuring monochromatic UV in the presence of a source producing scattered UV-VIS and a detector sensing it. The test is similar in principle to the ASTM E387 Test used for spectrophotometers. The test first records the signal at 210 and 250 nm. Then, all the real signal is blocked by insertion of a glass plate; what remains is scattered radiation.

** This measurement is primarily an indicator of the grating quality.

Instrument Control

We have made it as easy as possible to harness all the power of the Cornerstone 130. We offer two models: one with RS232 and IEEE-488 interfaces, and the other with a USB 2.0 interface. The optional Oriel remote hand controller is usable with either model. You can communicate with either version of the Cornerstone 130, in one of 3 manners.

Hand Controller

The 74009 Hand Controller is a dedicated interface just for the Cornerstone Monochromator Family. There is no need to memorize commands or key sequences; the 24 keys are clearly labeled with functions like “Step Up,” “Go Wave,” and “Shutter”. The backlit LCD display provides constant information on grating lines/mm, filter wheel position, current wavelength, and shutter status. The 74009 provides intuitive access to nearly all the functionality of the Cornerstone 130.

Computer Control

The computer interface was also designed for simplicity and ease of use. The Cornerstone ASCII command set is simple to use via RS 232 or GPIB. For example, close the shutter is “SHUTTER C” and change to the second grating is “GRAT 2”.

Complete Software Packages

We offer various software applications for Cornerstone:

Interchangeable Gratings

Each Cornerstone 130 grating comes mounted in its own pre-adjusted holder. Thus, the gratings are individually replaceable in the field. If, or when, your experiment changes, if you move to a new wavelength range, or if you require greater resolution - just order the single grating you need. There is no reason to send your entire system back, or to purchase multiple gratings all at once. Changing a grating takes only a few minutes and you will get repeatable results every time. The Cornerstone 130 holds two gratings simultaneously; if you wish to only use one grating, you will need to order the 74005 Grating Place Holder.

We offer a complete range of holographic and ruled gratings. Our standard Cornerstone gratings are listed in Table 1. Special gratings can be provided as well; contact a Sales Engineer with your requirements.

Table 1 Grating Specifications for Cornerstone 130 1/8 m Monochromator

These gratings are mounted in pre-adjusted holders which can be inserted and removed, at any time, from the Cornerstone 130.
 Line Density (I/mm)  Blaze Wavelength  Type  Reciprocal Dispersion (nm/mm)*  Peak Efficiency (%)  Primary Wavelength Region **  Instrument's Upper Wavelength Mechanical Limit
(for specificed grating)		  Model
 3600   405 nm  Holographic  1.7  60  180 - 405 nm  530 nm  74020
 2400   250 nm  Holographic  3.3  65  180 - 750 nm  800 nm  74021
 1800   500 nm  Holographic  4.1  80  300 - 1070 nm  1070 nm  74022
 1200   250 nm  Holographic  6.7  65  180 - 650 nm  1600 nm  74023
 1200   350 nm  Ruled  6.6  80  200 - 1600 nm  1600 nm  74024
 1200   750 nm  Ruled  6.2  85  450 - 1600 nm  1600 nm  74025
 600   200 nm  Ruled  13.3  70  180 - 500 nm  3200 nm  74026
 600   750 nm  Ruled  13.2  75  450 - 2000 nm  3200 nm  74027
 600   1 µm  Ruled  13  80  600 - 2500 nm  3200 nm  74028
 600   1.6 µm  Ruled  12.2  90  900 - 3000 nm  3200 nm  74035
 300   2 µm  Ruled  26  90  1100 - 5000 nm  6400 nm  74029
 200   1 µm  Ruled  40  85  600 - 2200 nm  9600 nm  74030
 150   800 nm  Ruled  53  80  425 - 1600 nm  12.8 µm  74034
 150   6 µm  Ruled  52  75   4.5 - 12 µm  12.8 µm  74031
 75   7 µm  Ruled  105  80   4.5 - 20 µm  25.6 µm  74032
 50   12 µm  Ruled  157  80   7 - 23 µm  38.4 µm  74033

* At blaze wavelength

** The primary wavelength region is where the grating efficiency is ≥20%. System efficiency will also be affected by the reflectivity of the mirrors and the grating angle, at any wavelength.

Three Types of Slits

We offer three types of slit assemblies for the CornerstoneTM 130. Choose the same size and type of slit for the input and output of your monochromator. All our slit assemblies have a 1.5 Inch Series male flange.

Micrometer Driven Slit Assembly
  • Continuously variable width from 4 µm to 3 mm
  • Continuously variable height from 1 to 15 mm
  • ±10 µm repeatability
  • ±10 µm accuracy from 4 to 250 µm, ±5% from 250 µm to 3 mm

This slit assembly uses a precision micrometer drive to adjust the width.

Multiple Fixed Slit Assembly
  • 8 fixed slit positions from 50 µm to 3.16 mm
  • Slit height is adjustable from 1 to 12 mm

This assembly consists of a rotating disc with 8 fixed slits. A manual wheel rotates the disc, which has a positive detent for exact repeatability of slit position.

Fixed Slit Assembly
  • Most economical for single slit size
  • Fixed width and height

If you only need a few slit sizes, this is the most economical choice. These are precision slits fixed on a machined slide. You need the 77294 Fixed Slit Holder to hold the slit and mate it to the monochromator.

Optional Motorized Filter Wheel

Choose the 74010 Motorized Filter Wheel to hold order sorting or neutral density filters. The 74010 holds six 1 inch (25.4 mm) diameter filters with no reduction in F/# (clear aperture, 0.87 inch (22 mm). Cornerstone™ 130 controls the 74010. Filter changeover is only 1.5 seconds for adjacent filters.

Simple Filter Interchange

With most filter wheels, you have to break down the setup to change filters, but with the 74010, the filters are held in individual mounts that snap into place from the top of the wheel. Six individual filter holders are included with each 74010 Filter Wheel. We also offer these separately under model 74011. Mount all your filters in 74011 Holders to protect them and have them ready for insertion into the filter wheel. The 74012 Rod Mount holds a 74011 Filter Holder atop an optical rod.

Mounting

Cornerstone™ 130 has 1/4-20 tapped holes in the bottom for rod mounting. To hard mount the instrument to an inch or metric optical table or to a rail carrier, order the 74006 Mounting Plate. The plate adds 0.25 inch (6.35 mm) to the 1.4 inch (35.6 mm) optical height. To simplify alignment of an Oriel Light Source to Cornerstone, we offer mounting kits.