MS260i Spectrograph with 3 Track Fiber on input and InstaSpec CCD on output.
The MS260i ¼ m Imaging Spectrographs are economical, fully automated, multi-grating instruments. We offer single and dual output models with dual and triple grating mounts. All are F/3.9 instruments with a flat, 28 mm image plane for multichannel detectors. Stray light is negligible, re-entrant spectra are eliminated, throughput is high, and spatial and spectral resolution are impressive. And, they are now offered with USB 2.0 interfaces. RS-232 and IEEE-488 interfaces are also still available.
The MS260i Spectrographs are an economical alternative to our fully featured, 1/4 m Monochromator and Imaging Spectrograph. To keep costs down, we removed some of the features from the MS257, without compromising performance. The result is a family of instruments with very good spatial and spectral resolution. The dual grating instrument offers improved resolution, over the triple grating instrument. Spatial resolution is 40 µm for the dual grating model, compared to 50 µm for the triple grating version. The grating mounts are interchangeable, so if you currently have a triple grating MS260i, you can easily convert it to a dual grating instrument. Simply choose two "Dual Grating Assemblies". These assemblies mount directly to the turret in your MS260i.
Fig. 1 shows the asymmetrical in-plane Czerny-Turner optical configuration of a dual grating MS260i. The input F/# is F/3.9, and the input and exit focal lengths are unequal 220 and 257 mm. A set of computer optimized toroidal mirrors produce accurate images of the input slit in the flat output plane. The superior spatial resolution of the MS260i sets it apart from most other imaging spectrographs; the aberration limited spatial resolution is 40 µm (FWHM), for the dual grating instrument.
Multi-track Spectroscopy is the simultaneous recording of multiple spectra. One of the factors limiting the number of spectra which can be recorded simultaneously is the spectrographs magnification. MS260i uses toroidal mirrors instead of the more common but poorly imaging spherical mirrors. The result is a 1.1 horizontal and 1.6 vertical magnification. It is important to note here that both the dual grating and the triple grating MS260i Spectrographs have the same magnifications, and can therefore resolve the same number of tracks from Multi-track Fiber Bundles. However, the image quality from a dual grating MS260i is superior to that from a triple grating instrument.
We offer single and dual output port MS260i Imaging Spectrographs. The dual output port instruments give you added versatility without compromise in performance; you can mount a silicon array on one port and an InGaAs array on the other, for extended wavelength measurements. These have a motorized flip mirror to switch between ports; the flip mirror can be controlled via the 74009 Hand Controller or MS260i Command Set.
One of the design criteria for MS260i was to mimimize stray light. It is important that diffracted light not be allowed to reflect from the mirrors, or from the face of a focal plane detector, back onto the grating. This light could then be rediffracted and cause ghost images or stray light at the detector. The wide open optical layout and exaggerated tilt of the exit focal plane of the MS260i ensure that there is zero re-entrant spectra.
We offer MS260i Spectrographs with USB 2.0 or with RS232 and IEEE-488 interfaces. You can communicate with any of the MS260i instruments in one of 3 manners.
The 74009 Hand Controller lets you set the instrument parameters and perform all the functions of the MS260i, e.g. wavelength changes, grating change and open/close shutter, and it controls the MS260i accessories such as the filter wheel. The 74009 is a dedicated hand controller; this means that the keys are labeled with intuitive commands, e.g. Go Wave, so you dont have to memorize key sequences to perform a function. Instrument parameters (grating lines/mm, filter wheel position, current wavelength and shutter status) are always displayed on the backlit LCD.
The computer interface was also designed for simplicity and ease of use. The MS260i 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. The USB version utilizes an ActiveX control for ease of programming via VB, LabView, Excel, MatLab or any application supporting ActiveX controls.
We offer various software applications for the MS260i:
The MS260i holds two or three gratings simultaneously (depending upon the grating assemblies that you choose). Each grating is mounted in an individual, pre-aligned mount. If you intend to use the Spectrograph as a dual grating instrument, order two grating assemblies from the "Dual Grating Assemblies" listed in the gratings ordering table. If you intend to use the MS260i as a triple grating instrument, choose your gratings from the "Triple Grating Assemblies" list. For detailed gratings performance specifications please see www.newport.com.
You can add and change gratings in the field without changing the instrument's grating turret. However, you may have to replace your current grating assemblies. If you want to change a dual grating instrument to a triple grating instrument, you cannot simply order a third grating; all three of your gratings need to be Triple Grating Assemblies. Equally, if you wish to convert your Triple Grating MS260i to a Dual Grating instrument (to improve resolution), you can't simply remove one grating; you will need to order two new Dual Grating Assemblies.
The MS260i requires an input slit assembly; we offer four types. All have a 1.5 Inch Series male flange. Mate any female flanged component directly to the slit.
This is our most versatile slit assembly. Change your instruments resolution by varying the slit width from 6 µm to 2 mm, in 6 µm steps. To operate a motorized slit, you also need the 74116 Slit Control Board; this board operates up to three motorized slits. Control is via the 74009 Hand Controller, or software.
The 74001 Slit Assembly offers you the greatest flexibility to change widths. A precision micrometer opens the assembly from 4 µm to 3 mm wide.
The 77269 is a rotating disc with 8 fixed and detented slits. A manual wheel rotates the disc to the desired slit position.
If you only need a few slit sizes, a fixed slit assembly is the most practical choice. Order the 77294 Fixed Slit Holder and one or more fixed slits. It allows you to interchange slits without losing position.
The 74010 Filter Wheel holds up to six 1.0 inch (25.4 mm) diameter neutral density or bandpass filters; the clear aperture is 0.87 inch (22 mm). It mounts directly to the input port of the MS260i. Even with the 74010 attached, the spectrograph F/number is still F/3.9.
The MS260i controls will also command the filter wheel. Filter changeover is only 1 second for adjacent filters. Filters are held in individual mounts which screw into place from on the wheel.
A 0.5 Hz repetition rate shutter is built into the MS260i. You can close the shutter for dark current measurements, or when changing a grating, to protect the detector. A shutter is required for almost all CCD applications (except full vertical binning mode). Minimum exposure time for the shutter is 0.2 s. The shutter is activated from the MS260i controls or via an externally applied TTL gate.