SPI YAG Single Crystal Discs for TEM screen Applications

Your viewing screen will now last forever!

Single Crystal YAG, doped with trivalent cerium can be used as a transparent screen in TEMs and various other electron optical devices. Although for the TEM application, its efficiency is slightly lower than for powder screens, but it has very high resolution, far better in fact than what would be possible with a powder and in addition, it is almost indestructable by the beam itself (at least in comparision to a powder screen).

We are also able to offer these single crystal scintillator materials in different forms and shapes, suitable for use in wide range of other applications including BSE (back scattered electron) detectors. Double detectors have been reported for both secondary electron (SE) and BSE imaging, while being connected to the same PMT.

When used as TEM viewing screens, the YAG must always be coated for surface conductivity. It is not possible to use these screens without conductive coatings. The kind of coating to be specified will be determined by the desired characteristics of the viewing screen:

 Aluminum coating:   
    -  for electron energies > 4 keV 
    -  higher light output compared to oxide or carbon layer 
    -  higher resolution compared to Al coating 

 Carbon coating: 
    -  for electron energies > 3 keV
    -  lower light output compared to Al coating
    -  higher contrast compared to Al coating

 Oxide coating: (Primarily TinOxide)
    -  for electron energies > 1.5 keV
    -  lower light output compared to Al coating
    -  lower contrast compared to Carbon coating
    -  higher contrast compared to Al coating
    -  very resistant to degradation from electron beam. 
              Unlimited lifetime! 
    -  Available for very high electron energies
    -  higher resolution compared to Al coating
 
       Oxide layer is made not only from tin oxide. It is a mixture
       of several oxides to ensure an increase in conductivity at a very
       low layer thickness.

Special note about EBSD (Electron Back Scatter Diffraction Pattern) applications:

Single crystal YAG has been used successfully in this application. However, not all users who have tried YAG in this application seem to be universally happy. Some have found what they believe to be lower contrast for the YAG screen relative to what they would have expected had they been using a normal powder P-20 coated screen. The explanation proffered as to the reason for the less-than-hoped for performance is that there are more internal reflections in the case of the YAG. So since this question has come up from time to time, we wanted to share this experience with our customers. We are looking for anyone who might share with us, and for a possible posting here on the website, of anyone else's experiences, good or bad, when using the SPI or any other brand of YAG scintillator discs for the EBSP application.

UNCOATED
disc dia. (mm)	thickness (mm)	SPI #	Each
20-24	0.35	03100-AB	$ 805.61
25-29	0.35	03101-AB	1070.42
30-34	0.35	03104-AB	1277.06
35-39	0.35	03102-AB	1419.40
40-41	0.35	03103-AB	1914.32

20-24	0.15	03105-AB	947.66
25-29	0.15	03106-AB	1227.61
30-34	0.15	03109-AB	1372.32
35-39	0.15	03107-AB	1572.87
40-41	0.15	03108-AB	2589.52

ALUMINUM COATED
disc dia. (mm)	thickness (mm)	SPI #	Each
20-24	0.35	03100A-AB	$ 863.31
25-29	0.35	03101A-AB	1129.05
30-34	0.35	03104A-AB	1343.58
35-39	0.35	03102A-AB	1476.99
40-41	0.35	03103A-AB	1971.84

20-24	0.15	03105A-AB	1005.10
25-29	0.15	03106A-AB	1285.17
30-34	0.15	03109A-AB	1529.36
35-39	0.15	03107A-AB	1630.46
40-41	0.15	03108A-AB	2647.01

CARBON COATED
disc dia. (mm)	thickness (mm)	SPI #	Each
20-24	0.35	03100C-AB	$ 863.31
25-29	0.35	03101C-AB	1129.05
30-34	0.35	03104C-AB	1343.58
35-39	0.35	03102C-AB	1476.99
40-41	0.35	03103C-AB	1971.84

20-24	0.15	03105C-AB	1005.10
25-29	0.15	03106C-AB	1285.17
30-34	0.15	03109C-AB	1529.36
35-39	0.15	03107C-AB	1630.46
40-41	0.15	03108C-AB	2647.01

OXIDE COATED
disc dia. (mm)	thickness (mm)	SPI #	Each
20-24	0.35	03100O-AB	$ 863.31
25-29	0.35	03101O-AB	1129.05
30-34	0.35	03104O-AB	1343.58
35-39	0.35	03102O-AB	1476.99
40-41	0.35	03103O-AB	1971.84

20-24	0.15	03105O-AB	1005.10
25-29	0.15	03106O-AB	1285.17
30-34	0.15	03109O-AB	1529.36
35-39	0.15	03107O-AB	1630.46
40-41	0.15	03108O-AB	2647.01

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