SPCS - Department of Physics and Astronomy Raman System
Topic outline
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Please find below the Raman system booking schedule. When selecting your hourly slots please keep in mind that these include the arrival and setting up time as well as the time to complete your experiments before arrival of other users.
Please note that access to the scheduling of you Raman session will only be granted once the following training has been completed:
1. General laser safety training.
2. Raman system operation.Please remember to enter the values of the reference peak position (obtained from the internal standard) and intensity of the reference peak in counts per second (cps) into the booking system once you collected these data at the start of your experiment. This is important for monitoring system health and booking restrictions will be introduced should a user fail to enter this information.
Please also remember to include (upload) your experimental risk assessment at the time of booking.
Please keep in mind that the system start-up and shut-down are part of your booking time. Start-up, in particular, may require up to 25-30 minutes for stable system operation.
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The Raman system is equipped with laser safety interlocks to prevent any accidental user exposure to the laser radiation. For general laser safety information please watch the below an NPL video:
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Below, the brief system operation guide is provided.
Please note that you must complete the system training is provided by Dr Sam Eardley (s.eardley@qmul.ac.uk) before using the system.
Detailed information about system capabilities and operation can be found in the internal help system of the Renishaw WIRE software.
Please ensure that all sockets the system (PC, lasers and the spectrometer) is connected to are turned on.
Initial start up
Please note that you should allow 10-15 min warm-up time for stable operation of 785 nm and 633 nm lasers, and up to 30 mins for 325 nm and 442 nm lasers.
1. Start the control PC.
2. Turn on the laser(s) you intend to use using laser key(s). (Please also note that 325 nm laser requires UV optics installed and UV objectives to be used. Contact a technical officer if you need to use 325 nm laser).
3. Turn on the spectrometer using the black side switch.
4. Start WIRE 5.1 software and select "Reference unreferenced motors" when prompted. Wait for the system to initialise.
5. Allow further 10-15 minutes for the CCD detector to cool to the operating temperature.
You are now ready to calibrate the system.
System calibration
First of all, please ensure that the correct laser and grating combination are selected in the main menu as previous user may have used different setting. For example, if you can see 442 nm laser and 2400 grating combination in the main menu, but you intend to use 785 nm laser, then select 785 nm and 1200 grating combination. Calibration will not work without the correct setting in the main menu.
The system calibration is curried out by opening a calibration template - use "Measurement - Open Measurement Template". This will bring up a selection of calibration files - select the file appropriate for your wavelength (but remember to use only "xxx-si-ref" files) and load it. This will open data window - you are now ready for calibration. Select "Tools-Calibration-Quck Calibration" to complete the process. Run measurement and check that Si reference peak is located at 520 cm-1. The system may report a calibration error if the peak is not found at the expected location.
Should calibration be out by a few cm-1 go to "Tools-Calibration-Offset" and select appropriate offset, run the calibration procedure again and check that Si peak is at 520 cm-1. When selecting offset, please keep in mind that this is the value that will be subtracted form the current peak location. As such is the current peak location is 518 cm-1, then select offset of "-2" (without the quotes). Please note, that the system resolution is around 1 cm-1 (depending on the grating choice), hence no offset is required if Si calibration peak is located between 519 and 521 cm-1.
Sometimes, when the system is significantly out of calibration, the system may report an error in locating the peak and will provide you with the possible peak location: e.g. it may report that no peak was located around 520 cm-1, but the nearest peak is at 500 cm-1. In such a case, again, enter an appropriate offset (-20 in this case) and run the calibration again.
Important: Take a note and record the value of the Si calibration peak intensity (in cps) and Si peak position (in cm-1) for your reference the next time you use the system.
You are now ready to do your own experiment which can be done by setting up a measurement in "Measurement-Setup".
Sample measurements
The Raman microscope stage is set up for use of standard microscope slides. When loading a side with your sample, please make sure that an objective with the longest working distance (i.e. 5X) is in place. Otherwise, there is a danger of damaging an objective. In order to load a microscope slide with your sample, lower the microscope stage and pull the stage towards you using the lever on the microscope stage. Once the sample is loaded, return the stage back under the 5X objective and focus on your sample. Always start your sample alignment procedure with the lowest magnification objective (i.e. 5X, has the longest working distance) and move onto the desired objective in increments. Thus if the desired objective is 50X, then move in increments of 5X-20X-50X, with careful sample alignment at each step. Please remember that large magnification objectives have very short working distances ( less then 1 mm) and can be easily damaged if they come in contact with a sample (or the microscope slide). Please report any such incidents to Dr Sam Eardley (s.eardley@qmul.ac.uk) and Dr Andrei Sapelkin (a.sapelkin@qmul.ac.uk).
Shutting down the systemRemove all your samples from the microscope enclosure and close the door.
Shut down the WIRE software and PC.
Turn off the spectrometer.
Shut down the laser (lasers).
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Here are brief instructions on how to perform Raman mapping. More information can be found inside the WiRE help system.
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General description of the capabilities of the Renishaw inVia confocal Raman microscope can be found here.
Renishaw inVia Reflex Spectrometer System for Raman StreamLineTM spectral analysis and rapid imaging system.
Available laser wavelengths: 325 nm, 442 nm, 633 nm and 785 nm.
Typical data range: 100 cm-1 - 4000 cm-1 (maximum 30000 cm-1).
Typical wavelength range: 200 nm to 2200 nm
Detailed system specification:- Extremely high efficiency 250 mm focal length spectrograph (>30% throughput in spectrograph).
- Laser spot size continuously variable from 1 to 300 um (objective and excitation wavelength dependent) with fully optimised beam path.
- Automated Rayleigh filter changeover assembly.
- Automated, kinematically mounted, magnetically attached, Rayleigh line rejection filter set for 325 nm excitation, using paired filters, allowing ripple-free measurement for VIS/NIR PL down to 200 cm-1 from the laser line.
- Automated, kinematically mounted, magnetically attached, Rayleigh line rejection filter set for 442 nm excitation, using paired filters, allowing ripple-free measurement of the Raman spectrum to 200 cm-1 from the laser line.
- Rayleigh line rejection filter set for 633 nm excitation, using paired filters, allowing ripple-free measurement of the Raman spectrum to 100 cm-1 from the laser line.
- Automated, kinematically mounted, magnetically attached, Rayleigh line rejection filter set for 785 nm excitation, using paired filters, allowing ripple-free measurement of the Raman spectrum to 100 cm-1 from the laser line.
- Visible and UV lens sets motorised and kinematically mounted for optimised spectral resolution.
- Unique continually adjustable 'easy confocal' facility using motorised slit, with automated signal optimisation.
- Encoder feedback controlled grating stage with three gratings (2400 lines mm-1 (UV), 1800 lines mm-1 and 1200 lines mm-1) on interchangeable magnetic kinematic mounts.
- Unique 'extended scanning' facility for measurement of high resolution spectra with wider wavelength range than can be accommodated on a single CCD view, without any 'stitching' of spectra together. Spectral resolution continuously variable via CCD binning control.
- Extremely high efficiency 250 mm focal length spectrograph (>30% throughput in spectrograph).