To operate any monochromator, slits are required at the input and output port. Spectrographs typically have a slit at the input port and a camera holder at the output port. For monochromators, the slits should be the same width and height at all ports. The slits offered for use with Oriel monochromators and spectrographs all have 1.5-inch male flanges, allowing them to be easily connected to the wide variety of Oriel accessories and instruments. 

The resolution of the monochromator is related to the grating dispersion – a function of the grating design – and the slit width. Resolution at the blaze wavelength of the grating is calculated to be the reciprocal dispersion multiplied by the slit width. 

Available configurations:



The fixed slits slide into the 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 with excellent repeatability. They are a good choice when only a few slit sizes are required. They are sold separately to allow customized choices based on the needs of the application. When ordering, be sure to purchase fixed slits of the same model for the input port and output port(s). Order two fixed slits for single output models, and three fixed slits for the dual output port monochromators. Order one slit for a spectrograph.

77294_1Fixed slit holder without the slit installed.77294Fixed slit holder with a slit installed (slits ordered separately).

A micrometer adjustable slit assembly is continously variable from fully closed to 3 mm width. The narrowest practically achievable width is 4 µm. A height adjustment slide allows variation in the height from 2 to 12 mm. Benefits of the micrometer adjustable slits are flexibility and high throughput. Please note that optimum spectral resolution for any monochromator is obtained with short, narrow slits. This type of slit is designed primarily for versatility and convenience in changing resolution and throughput; fixed slits should be used for the utmost accuracy and repeatability, especially at high resolution.

74001Micrometer adjustable slit assembly. The slide shown on the right is used to adjust the height and the micrometer adjusts the width of the slit. Note that the input and output slits should be set to the same width and height.

A motorized slit assembly may be adjusted from 6 µm to 2 mm width in 6 µm steps. The slit width is controlled through the utility software, optional hand controller, optional TracQ Basic software or by using low level commands. An advantage of using motorized slits is that in addition to setting the slit widths individually, the software can be configured to an automatic bandpass setting. The software adjusts the slit widths to maintain the chosen bandpass as scans are performed using multiple gratings and either output port.

BPT-pg4-28aMotorized slits.

Oriel offers fixed slits in widths from 10 µm to 5.0 mm. Each of the fixed slits is mounted in a precision machined slide which is inserted into the 77294 or 77721 fixed slit holder.





 Compatible Monochromators and Spectrographs
Model Width (µm) Height (mm) 77250 Cornerstone 130 and 
Cornerstone 260 		MS125 MS260i MS257
77211 6320 18 • •


77212 3160 18 • •


77213 1560 18 • •


77214 1240 18 • •


77215 760 18 • •


77216 600 18 • •


77217 280 18 • •


77218 120 18 • •


77219 50 6 • •
• •
77220 25 3
• • • •
77221 50 3

• • •
77222 10 2
• • • •
77725 25 6


• •
77728 100 3

• • •
77729 100 10


• •
77730 200 3

• • •
77731 200 10


• •
77732 500 15


• •
77733 1000 15



•
77734 2000 20



•
77735 5000 20



•
77736 1500 15



•


*Actual slit height is 18 mm, usable height is 12 mm for all instruments except the MS257.