Optimization and Troubleshooting
58
Reducing the Number of Conversions
Each time an analog to digital conversion is made, some read noise is introduced. For
spectra that are imaged as essentially vertical slit images on the array, the pixels
illuminated in their vertical columns can be binned into superpixels, to be combined
before conversion to data points. Likewise, when spectral resolution is not a limiting
factor, the signals can also be horizontally binned into two-dimensional superpixels. The
limit on this is that the combined signal intensity for the most intense superpixel should
not exceed the ADC dynamic range. However, when signal levels in some pixels are at or
near the saturation level, acquiring a series of spectra using integrations of shorter
duration and summing them digitally provides a means to avoid saturation. Please refer to
your software manual for instructions on setting up binning.
Environmental Noise Reduction
Because of the extreme low internal noise characteristics of the liquid nitrogen and
thermo-electrically cooled sensors, precautions to minimize noise pickup from external
sources is recommended.
Although shielded, the detector head and cables can still be sensitive to strong
electromagnetic fields. For best results, the detection system should be isolated from
devices generating such fields. In instances where external field sources may be
hampering the detection system’s optimum performance, HORIBA Jobin Yvon
recommends the following:
•
Electromagnetic interference (EMI) from a variety of sources may be picked up
by the detection system’s sensitive analog conditioning circuitry. Try isolating
any other apparatus suspected to be a noise source by turning it off while
monitoring the CCD signal in real time. Typical sources of EMI are high power
lasers, vacuum pumps, and computer monitors. If possible, connect offending
equipment to power sources separate from the detector controller and re-route
cables away from interfering devices.
•
Note that the room lights may radiate EMI based on the (50 or 60 Hz) power line
frequency. A battery-powered flashlight will not.
•
If turning off the spectrometer power switch reduces noise, rearrange power
connections to be sure the spectrometer, source, and detector are tied to the same
ground and, if possible, the same power circuit.
•
In extreme cases, such as working with or around high powered pulsed lasers or
other high energy apparatus, it may be helpful to construct RFI / EMI shields or
cages to contain the noise at its source, or to isolate the detection system from the
noise. In these cases, colleagues who are working with a similar apparatus may be
your best resource for noise control suggestions.
Summary of Contents for JOBIN YVON SYNAPSE
Page 1: ...SYNAPSE CCD Detection System User Manual Part Number 81100 Revision 2...
Page 10: ...Preface x...
Page 14: ...System Description and Specifications 4...
Page 28: ...Detector System Installation 18...
Page 38: ...Initial Power up and Operation 28...
Page 48: ...Temperature Control 38...
Page 72: ...Appendix A Dimensional Drawings 62 Figure 17 Distance from Focal Plane to CCD Chip...
Page 73: ...Appendix A Dimensional Drawings 63 Figure 18 Synapse Power Supply Unit...
Page 74: ...Appendix A Dimensional Drawings 64...
Page 86: ...Appendix C Performing Routine Procedures with SynerJY 76...
Page 100: ...Appendix E Accessories 90...
Page 104: ...Warranty 94...
Page 113: ...103 Notes...
Page 114: ...104 Notes...