4 grating turret with automatic grating switching
Two flat field output ports with automatic port switching
Negligible stray light and no re-entrant spectra
USB and RS-232 Communication
RS-232 can be configured with optional IEEE-488 (GPIB)
The MS257™ is a completely automated, efficient 1/4 m instrument, with enough versatility to satisfy most spectroscopy applications. It is an F/3.9 instrument with a focal length of 257.4 mm, usable as a monochromator or true flat field imaging spectrograph. Stray light is negligible, and there is no re-entrant spectra. The MS257 has 2 output ports, 1 input port (with optional accessory can support 2 inputs), and supports 4 gratings. USB and RS232 are standard. GPIB (IEEE488) communication is available using an external USB to GPIB converter sold separately.
| Model | Description | Availability | Price | Qty. | |
|---|---|---|---|---|---|
| 77782 | MS257 Series 1/4 m Imaging Spectrograph RS-232 / USB | Contact Sales |
The low F/number of 3.9 (a numerical aperture of 0.128) combined with slits of up to 5 mm wide x 20 mm high, gives an efficient throughput. The dispersion is similar to that of our other 1/4 m monochromators, and twice that of our 1/8 m systems. The mirrors and gratings in MS257 were designed to further enhance throughput. Each of the optics is uses an aluminum and a magnesium fluoride coating which improves their UV efficiency. (Contact a Sales Engineer for gold coated optics.) The 77708 Multiple Grating Turret allows you to choose up to four gratings to cover your wavelength range.
Fig. 1 MS257 Monochromator and Spectrograph with selected optional accessories
MS257 is designed around an asymmetric in-plane Czerny-Turner configuration. The input F/# is 3.9, and the input and exit focal lengths are unequal, 220.0 and 257.4 mm respectively.
Minimize coma throughout the working wavelength range
Eliminate re-diffracted light from either of the two main mirrors
Eliminate re-diffracted light from reflections off the window or surface of a focal plane detector
Provide the best flat focal field for the entire working wavelength range
Provide the best imaging using corrected optics (toroids) over the entire working wavelength range
MS257 has one entrance port and two output ports (see Fig. 2). Normally, the axial output port is used since this does not require a turning mirror and therefore prevents additional light losses at the extra reflecting surface. The in-line configuration of the lateral port offers greater detector mounting flexibility. To use just the lateral output port you’ll need the 77718 Side Exit Mirror. This mirror is aligned when Newport calibrates the MS257.
If you intend to use both output ports, and regularly switch between them, you should use the77716 Motorized Flip Mirror. You can pre-program MS257 to automatically change the output port at a particular wavelength. The mirror drive has excellent positioning reproducibility of better than 0.05 nm (with a 1200 l/mm grating). This precision is essential to obtaining reproducible scans when changing detectors in mid scan.
An Auxiliary Input Port, or Motorized Beam Steerer, is available to convert MS257 to a four port monochromator or spectrograph. This is an external accessory and has a motor driven mirror which is similar to the output mirror drive of the 77716 . It enables two sources to be alternately switched into the input port, for example a deuterium lamp and quartz halogen lamp (See Fig. 3). The mirror can be controlled through the MS257 command language. The optical path length of this Beam Steerer is 6.5 inches (165 mm).
Fig. 2 Lateral and axial ports of MS257
Fig. 3 Use the 77713 Motorized Beam Steerer to automatically switch between two sources
We offer a choice of optics for the MS257. The high quality spherical optics ensure excellent resolution over the full spectral range; choose these when MS257 is used for non-imaging applications. For imaging, we offer the 77782 MS257, which uses computer optimized toroidal mirrors. These produce accurate images of the input slit in the flat output plane.