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In XRR, what is the spot size? Or beam size that we collect...
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Kwok Cheik Chong
In XRR, what is the spot size? Or beam size that we collect...
Area probed during XRR measurements depends on incident beam size. In horizontal direction, probed width is given by horizontal beam size, whereas in vertical direction, beam footprint on the sample (=Vertical beam size/sin(theta), theta being glancing angle) defines the length probed during measurements. So, the length probed and hence, area probed during XRR vary with incident angle. For more information, you can check the article linked below:
So, it is preferable to use samples with size greater than beam footprint at critical angle of the material at incident energy. It can be done either by having bigger sample size or by decreasing vertical beam size using appropriate slits. In case both sample size and beam size can't be changed, you can go for measurements with knife edge so that only small region of the sample contributes to the reflected intensity. This is also given in the article linked above. Otherwise, you can perform footprint correction.
Area probed during XRR measurements depends on incident beam size. In horizontal direction, probed width is given by horizontal beam size, whereas in vertical direction, beam footprint on the sample (=Vertical beam size/sin(theta), theta being glancing angle) defines the length probed during measurements. So, the length probed and hence, area probed during XRR vary with incident angle. For more information, you can check the article linked below:
So, it is preferable to use samples with size greater than beam footprint at critical angle of the material at incident energy. It can be done either by having bigger sample size or by decreasing vertical beam size using appropriate slits. In case both sample size and beam size can't be changed, you can go for measurements with knife edge so that only small region of the sample contributes to the reflected intensity. This is also given in the article linked above. Otherwise, you can perform footprint correction.
Spot size is determined by your diffractometer setup. That is why it is only you who can know it for your own device. In the most usual case of the Bragg-Brentano geomery with fixed divergence slit the spot will have rectangular shape. Its width will be constant (usually between 10 and 20 mm). And its length will be determined by your choice of the slit width and goniometer radius. Also, spot length will be different at the different incident angles (but it is usually assumed that penetration depth will also change, so that the irradiated volume remains the same).
Spot size is determined by your diffractometer setup. That is why it is only you who can know it for your own device. In the most usual case of the Bragg-Brentano geomery with fixed divergence slit the spot will have rectangular shape. Its width will be constant (usually between 10 and 20 mm). And its length will be determined by your choice of the slit width and goniometer radius. Also, spot length will be different at the different incident angles (but it is usually assumed that penetration depth will also change, so that the irradiated volume remains the same).
But Nilay Maji , for completeness I want to add, that your statement '(but it is usually assumed that penetration depth will also change, so that the irradiated volume remains the same)' is only valid for angles well above the critical angle of total reflection.
But Nilay Maji , for completeness I want to add, that your statement '(but it is usually assumed that penetration depth will also change, so that the irradiated volume remains the same)' is only valid for angles well above the critical angle of total reflection.
Area probed during XRR measurements depends on incident beam size. In horizontal direction, probed width is given by horizontal beam size, whereas in vertical direction, beam footprint on the sample (=Vertical beam size/sin(theta), theta being glancing angle) defines the length probed during measurements. So, the length probed and hence, area probed during XRR vary with incident angle. For more information, you can check the article linked below:
So, it is preferable to use samples with size greater than beam footprint at critical angle of the material at incident energy. It can be done either by having bigger sample size or by decreasing vertical beam size using appropriate slits. In case both sample size and beam size can't be changed, you can go for measurements with knife edge so that only small region of the sample contributes to the reflected intensity. This is also given in the article linked above. Otherwise, you can perform footprint correction.
Area probed during XRR measurements depends on incident beam size. In horizontal direction, probed width is given by horizontal beam size, whereas in vertical direction, beam footprint on the sample (=Vertical beam size/sin(theta), theta being glancing angle) defines the length probed during measurements. So, the length probed and hence, area probed during XRR vary with incident angle. For more information, you can check the article linked below:
So, it is preferable to use samples with size greater than beam footprint at critical angle of the material at incident energy. It can be done either by having bigger sample size or by decreasing vertical beam size using appropriate slits. In case both sample size and beam size can't be changed, you can go for measurements with knife edge so that only small region of the sample contributes to the reflected intensity. This is also given in the article linked above. Otherwise, you can perform footprint correction.
Area probed during XRR measurements depends on incident beam size. In horizontal direction, probed width is given by horizontal beam size, whereas in vertical direction, beam footprint on the sample (=Vertical beam size/sin(theta), theta being glancing angle) defines the length probed during measurements. So, the length probed and hence, area probed during XRR vary with incident angle. For more information, you can check the article linked below:
https://arxiv.org/ftp/arxiv/papers/1804/1804.00839.pdf
So, it is preferable to use samples with size greater than beam footprint at critical angle of the material at incident energy. It can be done either by having bigger sample size or by decreasing vertical beam size using appropriate slits. In case both sample size and beam size can't be changed, you can go for measurements with knife edge so that only small region of the sample contributes to the reflected intensity. This is also given in the article linked above. Otherwise, you can perform footprint correction.
Regards,
Area probed during XRR measurements depends on incident beam size. In horizontal direction, probed width is given by horizontal beam size, whereas in vertical direction, beam footprint on the sample (=Vertical beam size/sin(theta), theta being glancing angle) defines the length probed during measurements. So, the length probed and hence, area probed during XRR vary with incident angle. For more information, you can check the article linked below:
https://arxiv.org/ftp/arxiv/papers/1804/1804.00839.pdf
So, it is preferable to use samples with size greater than beam footprint at critical angle of the material at incident energy. It can be done either by having bigger sample size or by decreasing vertical beam size using appropriate slits. In case both sample size and beam size can't be changed, you can go for measurements with knife edge so that only small region of the sample contributes to the reflected intensity. This is also given in the article linked above. Otherwise, you can perform footprint correction.
Regards,
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Spot size is determined by your diffractometer setup. That is why it is only you who can know it for your own device. In the most usual case of the Bragg-Brentano geomery with fixed divergence slit the spot will have rectangular shape. Its width will be constant (usually between 10 and 20 mm). And its length will be determined by your choice of the slit width and goniometer radius. Also, spot length will be different at the different incident angles (but it is usually assumed that penetration depth will also change, so that the irradiated volume remains the same).
Spot size is determined by your diffractometer setup. That is why it is only you who can know it for your own device. In the most usual case of the Bragg-Brentano geomery with fixed divergence slit the spot will have rectangular shape. Its width will be constant (usually between 10 and 20 mm). And its length will be determined by your choice of the slit width and goniometer radius. Also, spot length will be different at the different incident angles (but it is usually assumed that penetration depth will also change, so that the irradiated volume remains the same).
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But Nilay Maji ,
for completeness I want to add, that your statement '(but it is usually assumed that penetration depth will also change, so that the irradiated volume remains the same)' is only valid for angles well above the critical angle of total reflection.
But Nilay Maji ,
for completeness I want to add, that your statement '(but it is usually assumed that penetration depth will also change, so that the irradiated volume remains the same)' is only valid for angles well above the critical angle of total reflection.
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Area probed during XRR measurements depends on incident beam size. In horizontal direction, probed width is given by horizontal beam size, whereas in vertical direction, beam footprint on the sample (=Vertical beam size/sin(theta), theta being glancing angle) defines the length probed during measurements. So, the length probed and hence, area probed during XRR vary with incident angle. For more information, you can check the article linked below:
https://arxiv.org/ftp/arxiv/papers/1804/1804.00839.pdf
So, it is preferable to use samples with size greater than beam footprint at critical angle of the material at incident energy. It can be done either by having bigger sample size or by decreasing vertical beam size using appropriate slits. In case both sample size and beam size can't be changed, you can go for measurements with knife edge so that only small region of the sample contributes to the reflected intensity. This is also given in the article linked above. Otherwise, you can perform footprint correction.
Regards,
Area probed during XRR measurements depends on incident beam size. In horizontal direction, probed width is given by horizontal beam size, whereas in vertical direction, beam footprint on the sample (=Vertical beam size/sin(theta), theta being glancing angle) defines the length probed during measurements. So, the length probed and hence, area probed during XRR vary with incident angle. For more information, you can check the article linked below:
https://arxiv.org/ftp/arxiv/papers/1804/1804.00839.pdf
So, it is preferable to use samples with size greater than beam footprint at critical angle of the material at incident energy. It can be done either by having bigger sample size or by decreasing vertical beam size using appropriate slits. In case both sample size and beam size can't be changed, you can go for measurements with knife edge so that only small region of the sample contributes to the reflected intensity. This is also given in the article linked above. Otherwise, you can perform footprint correction.
Regards,
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