Mantis 5000 Spécifications télécharger pdf (Page 70)

14. If the standard reference option was used for the baseline scan, the reflectance

spectra is generated automatically. If the simple or zero baseline correction was selected

and the jaw style sample holder was employed, multiply the sample scan data by the

spectral reflectance factors for the calibrated reflectance standard or the data in Appendix

B. If using the clip style centre-mount sample holder, no correction is required.

Reflectance Measurements at the Reflectance Port (Small Spot Kit )

For samples loaded at the sample reflectance port, the DRA small spot kit can be used to

measure a particularly small test sample or a portion of a larger sample. Prior to entering

this procedure, the small spot kit should be installed and aligned. Mirror M3 must always

be installed at the "T" position for small spot kit measurements.

1. Install the centre-mount lens, marked "R", into the small spot kit lens holder. The

arrow marked on the lens should be pointing towards the sphere.

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

3. Remove the transmission sample holder from the dovetail at the integrating sphere

transmission port.

4. If the intended sample size is smaller than the reflectance port opening, secure a mask

over the port. The mask should be attached to the reflectance port, and it must remain in

place for both the baseline and sample scans. If available, the optional reflectance port

aperture kit, Labsphere Part No. AS-02021-000 can be used. If the sample is larger than

the port size, place a piece of translucent paper over the reflectance port sample holder

and install the holder at the port.

5. Adjust the iris aperture to full open.

6. Adjust the position of the small spot kit lens assembly on its dovetail rail, changing

the distance between the "R" lens assembly and the sphere until the beam spot obtained at

the reflectance port is crisp and well-focused. Make sure that the beam does not overfill

the edges of the sample. In general, the spot size and focus will be optimized when the

lens is moved closer to the sphere. If it is necessary to reduce the beam size to eliminate

sample overfilling, adjust the iris diaphragm until the spot on the sample fills

approximately 75% of the entire sample surface. Once the beam size is set, remove any

paper at the reflectance port of the sphere, so that the port or mask is open.

7. Load a calibrated diffuse reflectance standard against the reflectance port of the

sphere. The standard should be placed behind the sample port mask or aperture plate, if

one is used. Record one of the baseline scans as directed previously in this chapter.

8. Replace the reflectance standard at the sample reflectance port with the sample. Do

not change the configuration of the integrating sphere in any other way.

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Mantis 5000 Spécifications Page 70