Mantis 5000 Especificaciones descargar pdf (Pagina 62)

Variable Angle Reflectance Measurements (Centre-Mount Sample Holder)

The DRA can collect variable angle of incidence reflectance data when a centre-mount

sample holder is installed inside the integrating sphere. Shift mirror M3 to the centre-

mount position and align the transfer optics before proceeding with either of the

following procedures. The centre-mount sample holder should be employed only when

operating the instrument in double beam mode. Photometric accuracy of the variable

angle data may be reduced due to absorption characteristics of the sample holder

surfaces.

When using centre-mount devices, correct beam alignment is essential. Occasionally, the

requirement exists to conduct fine tune alignment of the beam inside the integrating

sphere. Rather than subject the sphere detectors to white light radiative flux, the operator

can drive the instrument to 500 nm and observe the beam path adjustments through the

accessory cover opening.

Note

Not all transfer optics are accessible through the sample compartment trap door,

and white light operation may be necessary.

To drive the instrument to 500 nm, select Goto from the Commands menu, enter 500 nm

and click OK. The sample compartment lid must remain shut in this mode of operation.

To establish white light operation temporarily, load beam blocks at the transmission and

reference beam entrance ports and select Align from the Commands menu.

Clip Style Sample Holder Measurements

1. Darken the room and drive the instrument to 500 nm

2. Mount the sample into the sample holder, making sure it is properly centreed and

secured to the holding clip. Load the assembly into the integrating sphere and set the

anticipated angle of incidence using the attached dial.

3. While viewing the sample surface through the reference port, check that the sample

beam strikes the centre and does not overfill the sample at the angle selected. This step

may require use of a piece of translucent paper and will be more difficult at greater angles

of incidence. If the beam is off centre or will not fit on the sample, either adjust the

sample mounting in the sample holder or readjust the sample beam optics to achieve the

correct alignment. If any adjustments are made to the optics, make sure the sample beam

does not clip the transmission port.

4. Examine the path of the reference beam inside the integrating sphere. The beam

should strike the reference port without clipping any part of the sample or sample holder.

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Mantis 5000 Especificaciones Pagina 62