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Labsphere DRA-CA-3300 Manual Download Page 44

AQ-00275-000, Rev. 3

43

Appendix B 

 

Typical Spectralon Reflectance Factors 

Wavelength

Spectralon 8

°

 Hemispherical Reflectance

250

.973

300

.984

400

.991

500

.991

600

.992

700

.992

800

.991

900

.991

1000

.993

1100

.993

1200

.992

1300

.993

1400

.991

1500

.992

1600

.992

1700

.988

1800

.989

1900

.981

2000

.976

2100

.953

2200

.973

2300

.972

2400

.955

2500

.960

Summary of Contents for DRA-CA-3300

Page 1: ...Measurements 17 0 Diffuse Reflectance Factor Measurements 18 Large Sample Reflectance Measurements 18 Transmittance Measurement Procedure 19 Theory of Operation 21 Double Beam Spectroscopy 21 Reflecta...

Page 2: ...es the means of measuring opaque turbid and reflecting substances using the same basic procedures used in traditional measurements Your DRA CA 3300 is an integrating sphere accessory that replaces the...

Page 3: ...absorbance measurements as before The DRA CA 3300 reflectance accessory is designed for use with the CARY 100 300 UV VIS Spectrophotometers The sphere accessory is an optical bench composed of double...

Page 4: ...Components DRA CA 3300 Accessory with instruction manual Tool Kit Three USRS 99 020 Uncalibrated Spectralon Reflectance Standards Center mount Port Plug Reflectance Port Light trap fits in sample hold...

Page 5: ...tance Standard Variable Angle Center mount Sample Holders VASH Clip used for analyzing thin films Variable Angle Center mount Sample Holders Jaw used for analyzing opaque rigid solids Fixed Angle Cent...

Page 6: ...er accessories from the instrument sample compartment 2 Slide the instrument sample compartment cover back Remove the compartment front panel Note the position of the detector DB connector inside the...

Page 7: ...trument Otherwise install the accessory with the cable unconnected 8 Position the accessory over the alignment pin in the back until the head of the assem bly fits tightly against the front panel of t...

Page 8: ...ports 15 Store the optics chamber cover handle and front panel to the spectrophotometer sam ple compartment in a safe place 16 Upon first time installation check the optical alignment of the accessory...

Page 9: ...e inch square of translucent paper that clearly displays the outline of the sample or reference beam when illuminated When performing this procedure the accessory control cable should be disconnected...

Page 10: ...need a one inch square of translucent paper that clearly displays the outline of the sample or reference beam when illuminated When performing this pro cedure the accessory control cable should be di...

Page 11: ...overfill the port b For transmittance measurements turn the adjustment screws of mirror M3 until the beam is centered on the transmittance sample port In this configuration the sample beam will overfi...

Page 12: ...ion manual contains the procedures for a series of diagnostic scans on your accessory These scans were performed on your accessory with our instrument before we shipped the DRA CA 3300 to you You shou...

Page 13: ...drive Note Be sure to remove the plate from the beam path when the scan is complete Light Trap Zeroline After completing an Uncorrected Baseline scan as described above perform a light trap zeroline a...

Page 14: ...as listed on the Labsphere diagnostic scan reports in the quality assurance documentation 2 Change the instrument configuration to Single Front beam mode from the Setup Dia log Box 3 Place a Spectral...

Page 15: ...pplications Integrating Sphere The integrating sphere assembly shown in Figure 6 is 150 mm in diameter and constructed of Spectralon Spectralon is the same material used on the standards supplied with...

Page 16: ...om well of the sample compartment When the cable is plugged in correctly the instrument will recognize the presence of the DRA CA 3300 accessory during initialization Optical Chamber The optical chamb...

Page 17: ...e the reflecting surface lies flat against the wedge and completely fills the port surface area In some instances you may need to load a light trap at the reference or sample reflectance port A light...

Page 18: ...ion provides an unfocused spot size of approximately 20 mm wide x 25 mm high Place the mirror in the center mount position if an intermediate beam size is desired The 8 reflectance measurement capabil...

Page 19: ...1 Replace the 8 sample wedge with the 0 wedge at the sample reflectance port 2 Load the calibrated SRS 99 020 diffuse standard into the sample port and the uncali brated standard at the reference por...

Page 20: ...x 9 5 mm high If a large transmittance spot size is desired such as for the measurement of fabrics or other homogeneous samples place mirror M3 in the reflectance R position This mirror configuration...

Page 21: ...nown as the regular transmittance factor For this particular accessory how ever the regular transmittance factor of a scattering sample closely approximates the total trans mittance of the sample Diff...

Page 22: ...io recording spectrophotometer the measurement of reflectance factor and transmittance involves the performance of a Baseline Correction based upon values recorded in an Uncorrected Baseline Baseline...

Page 23: ...e or eliminate the effect of such factors on transmittance and reflectance factor measurements In transmittance measurement the transmittance Ts of a non scattering sample placed in the path of the sa...

Page 24: ...on described in this manual The foregoing account involves two simplifying assumptions that bear further discussion First the efficiency of the integrating sphere represented by s and r is not necessa...

Page 25: ...be measured rela tive to a standard with similar geometrical scattering properties If calibrated standards that meet this criterion are not available as is often the case another approach must be take...

Page 26: ...he value M given in Equation 7 and its relation to the actual specular component of hemispherical reflectance S is described in Equation 12 On this analysis the best estimate for the 8 hemispherical r...

Page 27: ...e scan and record the measurement data The light trap reflectance is 0 3 Compute the corrected reflectance factor for the sample s as follows where r is the reflectance value of the reference standard...

Page 28: ...surface of your sample should coincide with the inside surface of the sphere wall Most sample surfaces however are not spherical in design so that some small portion of diffuse reflection may be direc...

Page 29: ...cations A variable angle center mount sample holder enables the sample reflectance and absorbance to be studied at various beam incidence angles The typical variable angle center mount sample holder u...

Page 30: ...ntegrating sphere and may interfere with the radiance uniformity at the wall surface Edwards Style Center Mount The Edwards attachment can be used to measure the variable angle reflectance of diffuse...

Page 31: ...iffuse samples can be measured using this sample holder in an absolute fashion Specular reflectance samples may be measured with the Edwards attachment if it is used in a relative mode and the sample...

Page 32: ...mples at sphere center An illustration of a jaw style sample holder is shown in Figure 13 The jaws easily will accommodate sample sizes up to 1 5 in length and width This is the size of a Labsphere SR...

Page 33: ...the transfer optics in the accessory 1 Load the sample into the sample holder making sure it is properly centered and secured to the holding device 2 Load the sample holder into the center mount port...

Page 34: ...suring turbid samples such as sea water proteins and other biological solutions Measurements performed with this device are in the diffuse specular excluded geometry Since the CMSH 3300 CUV is fixed a...

Page 35: ...transfer optics using the procedure under Aligning the Accessory Optics this time shifting mirror M3 to the C position When aligning M3 look into the sphere using the translucent paper and ensure that...

Page 36: ...oles Take care when inserting or removing the center mount from the integrating sphere to avoid damaging the interior of the sphere 5 Set your instrument parameters 6 Perform an instrument baseline co...

Page 37: ...ally to achieve the desired sample den sity 4 When the powder cell holder is filled to the required density or when the sample reaches the top of the cell cavity carefully slide the quartz window back...

Page 38: ...e relative reflectance value changes with changes in the sample packing density If you wish to compare subsequent sample measurements then take care to ensure that sample presentation to the beam and...

Page 39: ...cuvette filled with your solvent 3 Set your instrument parameters Set the Y Mode on the Setup Dialog Box of your WinUV software to absorbance or T 4 Perform an instrument baseline correction 5 Replac...

Page 40: ...r handled with bare fingers However the mirrors do have a protective magnesium fluoride overcoat to allow cleaning if necessary The fol lowing procedure is recommended 1 Remove the mirror fixture 2 Sp...

Page 41: ...lems that develop when using an accessory can be traced back to the instrument itself check that your instrument light source is operating satisfacto rily Check that the accessory cord is securely att...

Page 42: ...the lifetime of the PMT by keeping the center mount port on top of the integrating sphere plugged and the accessory lid closed when not in use Except for optics alignment never run a scan or operate t...

Page 43: ...Reflectance Port 1 dia Transmittance Port 25 mm Measurement Capability Reflectance Total 8 Diffuse 0 Transmittance Total PMT Detector Hamamatsu R928 Spectral Range 185 900 nm Peak Wavelength 400 nm G...

Page 44: ...actors Wavelength Spectralon 8 Hemispherical Reflectance 250 973 300 984 400 991 500 991 600 992 700 992 800 991 900 991 1000 993 1100 993 1200 992 1300 993 1400 991 1500 992 1600 992 1700 988 1800 98...

Page 45: ...n from a surface varies as the cosine of the angle between the normal to the surface and the direction of the direc tion of the emitted flux also called Lambert s cosine law mixed reflection partly sp...

Page 46: ...ance factor the ratio of the flux transmitted by a specimen and evaluated by a receiver to the flux passing through the same optical system and evaluated by the receiver when the speci men is removed...

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