Method of performing spectroscopy in a transmission charged-particle microscope

1. A Transmission Charged-Particle Microscope, comprising:

a specimen holder, for holding a specimen;

a source, for producing a beam of charged particles;

an illuminator, for directing said beam so as to irradiate the specimen;

an imaging system, for receiving a flux of charged particles transmitted through the specimen and directing it onto a spectroscopic apparatus comprising:

a dispersing device, for dispersing said flux into an energy-resolved array of spectral sub-beams distributed along a dispersion direction; and

a detector

including an assembly of sub-detectors arranged along said dispersion direction, whereby different sub-detectors are adjustable to have different detection sensitivities.

2. A microscope according to claim 1 , wherein:

said detector is pixelated;

each of said sub-detectors comprises at least one pixel of the detector.

3. A microscope according to claim 1 , wherein each sub-detector is elongated along a transverse direction perpendicular to said dispersion direction.

4. A microscope according to claim 2 , wherein said detector comprises a pixelated array of avalanche photodiodes having individually adjustable gain values.

5. A microscope according to claim 2 , wherein said detector comprises a pixelated CMOS detector in which individual CMOS pixels have an adjustable parameter selected from the group comprising Conversion Gain, Full Well Capacity, and combinations hereof.

6. A microscope according to claim 2 , wherein said detector comprises a pixelated CCD detector.

7. A microscope according to claim 1 , wherein said detector comprises at least one of the following structures upstream of said assembly of sub-detectors:

a radiation-hardening layer;

a scintillation layer.

8. A microscope according to claim 1 , wherein said detector is back-thinned so as to mitigate electron backscattering within the detector.

9. A method of performing spectroscopy in a Transmission Charged-Particle Microscope, the method comprising:

providing a specimen on a specimen holder;

producing a beam of charged particles from a source;

using an illuminator to direct said beam so as to irradiate the specimen;

using an imaging system to receive a flux of charged particles transmitted through the specimen and direct it onto a spectroscopic apparatus comprising:

a dispersing device, for dispersing said flux into an energy-resolved array of spectral sub-beams distributed along a dispersion direction;

a detector

including an assembly of sub-detectors arranged along said dispersion direction, whereby different sub-detectors are adjustable to have different detection sensitivities;

adjusting said sensitivities to be:

relatively low in a first region of said array in which there is a relatively high charged-particle intensity;

relatively high in a second region of said array in which there is a relatively low charged-particle intensity; and

using said detector to perform simultaneous detection of said first and second regions.

10. A method according to claim 9 , wherein:

said first region comprises at least part of a feature selected from the group comprising an EELS Zero Loss Peak and an EELS Plasmon Resonance Peak;

said second region comprises at least part of an EELS Core Loss Peak.

11. A method according to claim 9 , wherein said adjusting of sensitivity occurs using at least one method selected from the group comprising:

calibration, whereby at least one test spectrum is analyzed so as to pre-determine charged-particle intensities in said first and second regions;

modeling, whereby mathematical calculation is used to predict charged-particle intensities in said first and second regions;

autonomous adjustment, whereby a given sub-detector can self-adjust its sensitivity in response to a received charged-particle intensity,

and combinations hereof.

12. A method according to claim 9 , wherein a first detection result from said first region and a second detection result from said second region are used to perform at least one action selected from the following group:

deconvolving said second detection result using said first and second detection results as input to a mathematical deconvolution procedure;

correcting for a contribution of an instrument-related transfer function in said second detection result;

determining an absolute energy scale for said second detection result;

determining an absolute intensity scale for said second detection result;

deducing a thickness of the specimen from a comparison of an integrated intensity of said first and second detection results;

using said first detection result as input to a feedback loop to adjust an output of a power supply connected to at least one of said source, illuminator, imaging system and dispersing device,

and combinations hereof.

13. An Electron Energy-Loss Spectrometer module comprising:

a dispersing device, for dispersing an input flux of electrons into an energy-resolved array of spectral sub-beams distributed along a dispersion direction; and

a detector

including an assembly of sub-detectors arranged along said dispersion direction, whereby different sub-detectors are adjustable to have different detection sensitivities.

14. The electron energy-loss spectrometer module of claim 13 , wherein said detector comprises a pixelated array of avalanche photodiodes having individually adjustable gain values.

15. The electron energy-loss spectrometer module of claim 13 , wherein said detector comprises a pixelated CMOS detector in which individual CMOS pixels have an adjustable parameter selected from the group comprising Conversion Gain, Full Well Capacity, and combinations hereof.

16. The electron energy-loss spectrometer module of claim 13 , wherein said detector comprises a pixelated CCD detector.

17. A microscope according to claim 2 , wherein each sub-detector is elongated along a transverse direction perpendicular to said dispersion direction.

18. A method according to claim 10 , wherein said adjusting of sensitivity occurs using at least one method selected from the group comprising:

calibration, whereby at least one test spectrum is analyzed so as to pre-determine charged-particle intensities in said first and second regions;

modeling, whereby mathematical calculation is used to predict charged-particle intensities in said first and second regions;

autonomous adjustment, whereby a given sub-detector can self-adjust its sensitivity in response to a received charged-particle intensity,

and combinations hereof.

19. A method according to claim 10 , wherein a first detection result from said first region and a second detection result from said second region are used to perform at least one action selected from the following group:

deconvolving said second detection result using said first and second detection results as input to a mathematical deconvolution procedure;

correcting for a contribution of an instrument-related transfer function in said second detection result;

determining an absolute energy scale for said second detection result;

determining an absolute intensity scale for said second detection result;

deducing a thickness of the specimen from a comparison of an integrated intensity of said first and second detection results;

using said first detection result as input to a feedback loop to adjust an output of a power supply connected to at least one of said source, illuminator, imaging system and dispersing device,

and combinations hereof.

20. A method according to claim 11 , wherein a first detection result from said first region and a second detection result from said second region are used to perform at least one action selected from the following group:

deconvolving said second detection result using said first and second detection results as input to a mathematical deconvolution procedure;

correcting for a contribution of an instrument-related transfer function in said second detection result;

determining an absolute energy scale for said second detection result;

determining an absolute intensity scale for said second detection result;

deducing a thickness of the specimen from a comparison of an integrated intensity of said first and second detection results;

using said first detection result as input to a feedback loop to adjust an output of a power supply connected to at least one of said source, illuminator, imaging system and dispersing device,

and combinations hereof.