The VS7550 is a miniature Czerny-Turner spectrograph with excellent speed, spectral range and spectral resolution with software control of slit size, input f#, order sorting filters, grating angle and dark exposures. For VUV operation, the spectrograph has a UHV window and laminar flow purge system, which allows operation down to the window short wavelength cut-off (112 nm for MgF2). The spectrograph is small enough to fit in your hand and can be fully operational in any orientation at the end of a 5- meter cable. Accessories include a built-in spectral calibration lamp, a multi-spectral field flat light source and low-cost accessories such as telescopes, vacuum adapters, and flow controllers.
•High speed Czerny Turner optics up to f/3.2 (at CCD)•Resolution better than 0.2 nm achieved with 3600 groove per mm grating•User interchangeable gratings from 600 to 4200 grooves per mm•104 to 1030 NM with 1200 g/mm grating•Computer controlled slit size from 25 to 400 microns•Computer controlled input aperture from f/3.2 to f/8.4•Computer controlled order sorting filters•Computer controlled grating angle means that full range of grating can be used by creating panoramic spectrum•Laminar flow purge system allows operation down to 104 nm•UHV interface with window so spectrograph can be removed from UHV chamber during bake out•Stable detector employs phosphor coating to eliminate history effects of back-thinned detectors in VUV. Sensitivity range from 100 to 1000 NM.•Simple USB interface for spectral acquisition and spectrograph control with up to 10 meter cable.•Extremely compact so remote operation is allowable•Accessories include built in calibration lamp, Flat fielding LED•NIST traceable calibrations are optional
Front 2.75 in flange can be attached to UHV chamber. Spectrograph is isolated with MgF2 window in vacuum adapter. Purge can be dry N2, Ar, or He.
The Spectrometer can be removed from a vacuum chamber without breaking vacuum. This allows bake out of the UHV chamber above the non-operational limit of the spectrometer.
•Changing all CCD parameters (wavelength coefficients, integration time)•Slit width control•Spectrograph wavelength range control•Spectrograph input aperture (input f#)•Spectrograph order sorting filter•Pixel or Wavelength display•Software activated darks•Data export (XLS user selectable)•Store multiple spectra and graph/save multiple spectra
Software and Drivers
A PC software package which controls all the spectrometer functions, displays and stores spectral data is provided.Capabilities include:
Quick Start Operating ProcedureConnect Purge Pipe1.Connect the ¼’swagelok valve connector to a purge gas supply. With valve closed pressurize supply arm to 5-20 psi. Open valve 1/8 turn and test flow of gas with finger at exhaust pipe. Only a slight flow is required to detect VUV radiation.2. VUV detection can be verified by setting spectrograph to a VUV angle setting. (e. g. -13deg for 3600 grating to observe emission spectra) in real time with valve on or off. Gas use can be conserved by fine tuning valve to have just enough gas flow rate to see VUV.Connect PC to Spectrograph1.Plug USB cables into USB ports on the PC and into spectrograph.2.Connect power supply to VS150 and turn on.3.Start VS150 Spectrometer Software. (note that the VS150 must be “On” before running software)
Set-up Software for Taking Spectra1.Make sure manual settings button is unchecked (this should be set by default). By checking the manual settings button you can fine tune slit, aperture and grating positions (it is highly recommended to leave these settings as they have been optimized for this specific unit).2.Select slit size from drop down menu. Slit settings determine resolution. See graph in appendix. 50microns is good for most applications.3.Set grating angle from drop down menu from -30 degrees to 4 degrees (1 degree increments). Most common grating angles are in the first 3 positions.4.For serial number 691, angle -13 deg covers 110nm to 205nm, angle -23 covers 165nm to 280nm and angle -30 covers 160nm to 317nm.5.Set aperture from drop down menu (for highest resolution use f8.4, for intermediate resolution use f4.8 and for highest sensitivity use f3.2) The aperture also has order sorting filters. VUV apertures are for wavelengths between 100nm and 230nm. The UV/Vis apertures are for wavelengths between 230nm and 320nm. The VIS/IR apertures are for wavelengths between 320nm and 1000nm. When observing VUV make sure VUV aperture is selected.6.Select integration time to input value, integration time 100ms; select averages, input 5 averages.7.After above steps have been carried out spectra will be continuously displayed after every integration time as seen with progress bar at top right of window.Operation During Spectral Acquisition1.Adjust integration time and averages while observing target. Most applications can use integration times of 100ms with 5 averages. To ensure good linearity maintain the region of interest below 3500 counts. Take dark (click the Dark button near the top mid-right of program). Wait for dark acquistion, then click the “-Dark” button. Dark must be taken at beginning of session and after every change to integration time for the best possible results.2.Wavelength/Pixel 3.Full Spectrum scan will record an automatic set of spectrum at predetermined angles.Storing and Saving Data1.The Store Spectrum button saves spectrum into temporary storage. Any selected stored plot is visible on screen.2.Stored plots can be saved and exported via right clicking on the spectrum window and selecting export spectra. There are 3 ways to save spectra: Single Plot (select a single plot to save), Selected Plots (saves all visible plots) and All Plots (saves all plots).3.Data is saved as a CSV format and can be opened in Excel.4.We advise you to save and delete after every 100 spectra to avoid cumbersome worksheets. BE SURE “ALL PLOTS” IS SELECTED IF SAVING ALL SPECTRA. Note that single plot will only save the current spectrum plot if no other plot is selected.
Optional KrLM Mini Light Source
Rotate the spindle to switch between the KrLM mini light source and external light source.
KrLM Mini Light Source (for calibration)1.Rotate spindle counter-clockwise until it touches the top-right pin (see above picture)2.Switch on light source by connecting DC power supply to lamp and AC outlet.3.If purge is off, no spectrum will be seen below 400nm. If purge is on, first and second order VUV spectra will be visible. (see Kr Cal Lamp spectrum next page)4.Follow operating procedure to view and obtain spectra.External Light Source (standard operation)1.Rotate spindle clock-wise until it touches the left pin.2.Follow operating procedure to view and obtain spectra.
TroubleshootingSoftware has lost connection to spectrometerA prompt will appear if connection between the VS7550 and software has been lost. This may be caused by a loose USB connection or the power to the VS7550 has been turned off. Also, depending on the proximity of the VS7550 to a strong electric current it may also cause disconnection. To remedy this, simply ground the VS7550 case. Connecting a grounding cable to the purge inlet will suffice. Close the dialog box, then click the “Exit” button (top right corner of window). If there is data that needs to be saved do so before clicking the “Exit” button. Unable to see SpectrumThere are a number of contributing factors that may lead to the inability to see spectrum. •In VUV, air in optical path.•Check purge and vacuum.•In all spectrum, check order sorter filter. A common mistake is having the UV aperture in place during a VUV scan.•Check slit size and integration time. Set to 100 microns and 1000 ms integration time as an initial test for spectrum.•Check pixel and auto scale X and Y, be sure to scale is wide enough to view