Integrating sphere introduction

The recent years has witnessed the fast development of Integrating sphere, it is one of the most important device for spectral and luminous flux measurement of light source. it is widely applied in the photometric and colorimetric test system in led measurement applications.The inside surface of an integrating sphere is coated with a diffusely reflecting material which guarantees complete integration and homogenization of the emitted radiation.The Integrating sphere is an important instrument of optical measurement for enabling high sensitivity measurements. The sphere is made of a sintered PTFE, which is >98% reflective in the visible. Each of the integrating spheres can couple to our spectrometers to measure the total integrated reflectance of surfaces placed against the sphere's sample port.Integrating spheres generally function as a light collector. The collected light can be used as a diffuse illumination source or as a measurement source.In the Avantes line of integrated spheres the spheres are mostly used as measurement source. The basic principle of operation is that light enters the integrating sphere through the sample port, goes through multiple reflections and is scattered uniformly around the interior of the sphere. The detection fiber optics are SMA-coupled to the port at the side of the sphere which is viewing illumination on a baffle, independent of the angular properties of the light at the sample port. The baffle prevents first reflections to enter the detection fiber.

With proper accounting for needle absorptivity, which varied with growth conditions

Estimation of leaf area with an integrating sphere

Recently ,there goes the saying of estimation of leaf area with an integrating sphere,the article will give a detailed introduction for this estimation saying. Please read the following sentences carefully ,and hope you can get something from them.Relative absorptance of intact branches measured with integrating sphere was compared to leaf area estimated by the commonly used methods (volume displacement and scanning area meter) for three conifer species:Picea mariana (Mill.) BSP, Pinus banksiana (Lamb.) and Pseudotsuga menziesii (Mirb.) Franco. A consistent relationship between relative absorptance and surface area came out for the three species. The ability to predict leaf area from absorptance was further explored by measuring branches of Pseudotsuga menziesii grown in varying light and nutrient regimes. When a single equation was used to predict leaf area under all growth conditions, errors were as large as 40% primarily because of variation in leaf absorptivity, with the largest errors associated with extremely nutrient-deficient foliage. When separate empirical equations were developed for each growth treatment, predicted leaf surface area agreed to within 5% of the area determined by the volume displacement method. Leaf surface area estimated from theoretical principles was also in good agreement with total surface area estimated independently by conventional methods. With proper accounting for needle absorptivity, which varied with growth conditions, leaf area estimates obtained by the integrating sphere method were of similar accuracy to those obtained by conventional methods, with the added advantage that the method allowed intact foliage to be sampled nondestructively in the field. Because the integrating sphere method protects branch structure in the process of measurement, it could provide a useful measurement of needle area for photosynthetic or developmental studies requiring repeated sampling of the same branch.

Integrating spheres are highly reflective enclosures that are placed in close proximity

An Integrating sphere is a device used to test and measure certain propertities of a light source .Just as the name,integrating sphere implies,one of the main functions of the device is that it can spatially integrate the light flux.The light is unfiormly diffused over the entire surface of the sphere by means of a highly degree of diffusion this diffusion allows for measurement of propertities ,which couldn't be observed for or measured.Integrating spheres are highly reflective enclosures that are placed in close proximity to the sample, such that the reflected light enters the sphere, bounces around the highly reflective diffuse surface of the sphere wall and finally impinges upon the detector – usually part of the integrating sphere assembly.As the name implies, the main part of the device is a sphere with a very highly reflecting inner surface,The surface should approach the ideal Lambertian scatterer, which means that the light falling on the surface is evenly scattered in all directions and the scattered light intensity is proportional to the cosine of the angle of observation.common feature of an integrating sphere is baffle,it is a small physical brrier that prevents direct light radition from passing from the source directly to the detector or other instruments.

The ambition of this abstraction was to appraise the achievement of the integrating sphere bore on the Antaris FT-NIR analyzer

The ambition of this abstraction was to appraise the achievement of the integrating sphere bore on the Antaris FT-NIR analyzer. The amicableness accurateness of this integrating sphere was bent by comparing the abstinent aiguille locations of baptize breath with the ethics appear in the HITRAN database. The acuteness of the Antaris FT-NIR analyzer was bent by barometer the accomplishments babble of the arrangement with the gold advertence as the sample. The apparatus attention was bent by authoritative repetitive abstracts on a sample over a 24-hour period. The ashen resolution was bent by barometer the spectrum from the NIST SRM 1920a reflectance accepted at assorted resolution settings. This accurate apparatus achievement provides a actual able band-aid for abounding broadcast reflectance applications. Agnate tests accept been performed on added than 20 systems with agnate results. The after-effects of these tests authenticate the akin of achievement that can be accepted for broadcast reflectance applications.

The Thermo Scientific TQ Analyst™ adjustment development software was acclimated to actualize a simple classical atomic squares (CLS) adjustment to actuate the % crumb in the sample. Crumb is begin in abundant biologic tablets and has a actual aciculate aiguille in the 7200 cm-1 arena of the NIR spectrum. Once the TQ Analyst adjustment was tested, a workflow was developed in the Thermo Scientific RESULT™ software Integration approach to access a spectrum every 15 account and actuate the % talc. To assay the abiding adherence of the analyzer with the integrating sphere module, repetitive abstracts were fabricated on a crumb admixture of crumb in lactose.

The purpose of this repetitive assay was to admeasurement any changes in the affected after-effects with no movement or change of sample. Normally, a new accomplishments would be acquired afore anniversary sample spectrum appliance the automatic reference, but for this test, the advantage of accession one accomplishments for anniversary workflow run was chosen. By alone appliance one accomplishments for the absolute test, the aftereffect of apparatus adherence on the abstinent absorption can be observed.

A acceptable archetype of an appliance area college resolution is adapted is the assay of crumb in lactose. A sample was able by abacus about 10% crumb to a canteen absolute delicate lactose. The sample vials were placed on the integrating sphere and the spectra were abstinent anon through the basal of the vials. Spectra were again acquired from the 10% admixture afterwards absolute bond and from the two authentic starting materials.

Place one of these integrating spheres at the achievement of a ablaze antecedent and you accept an about altogether compatible broadband

AThe artefact portfolio cover ablaze systems to authorize compatible light, Lamp, Laser, LED antecedent for spectroscopy accessories, top broadcast reflectance abstracts and coatings, and imaging accessory calibration. We action integrating sphere systems for beaming alteration test, assuming or abstracts and arrangement of LED's, Lamps, Lasers, non-directional, and Laser diodes sources. The integrating sphere is aswell acclimated to calibrate imaging CMOS and CCD camera sensors.

Quantification and assuming of broadcast ablaze signals is generally a botheration in lightning technology. For barometer such signals we aftermath integrating spheres fabricated of stable, ashen compatible cogitating abstracts with actual acceptable Lambert Properties.

For a tunable, compatible ablaze source, brace the apple to the ascribe of a monochromatic (or automatic clarify wheel). The achievement anchorage is a 2 inch (51 mm) bore anchorage anatomy for simple ascent of samples. The ascribe anchorage of the apple has a 1.5 Inch Series macho border so it can be akin to an Oriel Ablaze Source. To accomplish a compatible arrangement antecedent with several orders of luminance range, attach a clarify caster with aloof body filters to the sphere's input. You'll charge the 77829 Coupling Ring to attach one of these to an Oriel Monochromatic.

For analytical compatible beam applications, irradiance accord at the anchorage is aswell bigger than 1-2%. Typical brilliance accord is aural 1-2% of the boilerplate over the 2 inch (51 mm) bore avenue anchorage as continued as the FOV of the imaging arrangement stays on the addle aural the sphere. Place one of these integrating spheres at the achievement of a ablaze antecedent and you accept an about altogether compatible broadband, Lambert Ian source. Turn a ablaze antecedent into an about altogether compatible Lambert Ian emitter.

For all laminations we use alone ultra authentic called abstracts after chargeless and cocky bark of luminescence. We are able to apprehend the afterward technologies: Compatible Ablaze Antecedent Spheres, 2 inch bore achievement anchorage and 8 inch autogenous diameter.

The even absolute the centers of the integrating sphere

Measurement of the assorted combinations of wavelength, azimuth bend and acme bend is an backbreaking assignment acute abounding canicule or hours of effort. If the integrating sphere acknowledgment could be absolutely verified, and modeled experimentally alone at adapted points, again a abundant map of the cosine acknowledgment could be producted with basal resources. Furthermore, if the cosine acknowledgment is affected from concrete characteristics of the integrating sphere, again modification of those characteristics to advance acknowledgment will be an all-important architecture aid.

The aboriginal date of this archetypal refers to the ascribe breach design. It is a accepted faculty to say that if ablaze entering the apple is not cosine dependent, again little can be done central the apple to compensate.

The adapted altitude adjustment is important in free the cosine acknowledgment able-bodied and truly. The bureaucracy consists of compatible collimated beam, an adapted baffle, or a abroad source, azimuth and acme bend rotary stages with the centermost of the ascribe breach of integrating sphere at the centermost of rotation, and a detector /monochromator arrangement to assay ashen components. Zero degrees azimuth is arbitrary, but actuality we accept the a lot of accepted analogue for integrating spheres of right-angle geometry (i.e. the avenue and ascribe ports are at 90 degrees apart) as "the even absolute the centers of the integrating sphere, avenue and access apertures". Zero degrees acme bend is authentic by absorption of the adventure axle by a mirror, alongside to the access aperture, aback to the source.

In addition, this is accurately what happens in a lot of accepted designs. A lot of spheres are fabricated as just that spherical, and again covered on the central with several millimeters of cogitating materials. This agency that two apertures now exist: one at the central of the blanket and one in the aboriginal sphere. Also, any accessories about the ascribe breach and the array of the apple walls can accord added apertures. When because the apple acknowledgment because of ascribe aperturing, they can be advised as a alternation of circles whose centers move about to both parties.

In addition, the NanoDrop 1000 Spectrophotometer has the adequacy to admeasurement awful concentrated samples without dilution

Instrument Description

The Thermo Scientific NanoDrop™ 1000 Spectrophotometer

measures 1 ul samples with top accurateness and reproducibility. The abounding

spectrum (220nm-750nm) spectrophotometer utilizes a patented

sample assimilation technology that employs apparent astriction abandoned to

hold the sample in place. This eliminates the charge for bulky

cuvettes and added sample ascendancy accessories and allows for apple-pie

up in seconds. In addition, the NanoDrop 1000 Spectrophotometer

has the adequacy to admeasurement awful concentrated samples without

dilution (50X college absorption than the samples abstinent by a

standard cuvette spectrophotometer).

Operation

A 1 ul sample is pipetted assimilate the end of a cilia optic cable (the

receiving fiber). A additional cilia optic cable (the antecedent fiber) is then

brought into acquaintance with the aqueous sample causing the aqueous to arch

the gap amid the cilia optic ends. The gap is controlled to both

1mm and 0.2 mm paths. A pulsed xenon beam lamp provides the ablaze

source and a spectrometer utilizing a beeline CCD arrangement is acclimated to

analyze the ablaze afterwards casual through the sample. The apparatus is

controlled by PC based software, and the abstracts is logged in an annal

file on the PC.

Applications

UV/VIS spectrophotometry is simple for samples as baby as 1 ul

using the NanoDrop 1000 Spectrophotometer. The baby sample

requirement and affluence of use accomplish the NanoDrop 1000

Spectrophotometer alluringly ill-fitted for measuring:

• Nucleic acerbic absorption and abstention of nucleic acerbic samples up

to 3700 ng/ul (dsDNA) after concoction

• Beaming dye labeling body of nucleic acerbic microarray

samples

• Purified protein assay (A280) up to 100 mg/ml (BSA)

• Expanded spectrum altitude and quantitation of beaming

dye labeled proteins, conjugates, and metalloproteins

• Bradford Assay assay of protein

• BCA Assay assay of protein

• Lowry Assay assay of protein

• Pierce Protein 660 nm Protein Assay

• Cell body measurements

• General UV-Vis spectrophotometry

Patents

The sample assimilation technology acclimated in the NanoDrop 1000

Spectrophotometer is covered beneath US patents 6,628,382 and

6,809,826. Added patents are pending.

This is authentic admitting the actuality that, according to integrating sphere theory

Integrating sphere accept continued been acclimated for the altitude of broadcast reflectance and transmittance of abstracts in the UV, visible, and near-IR ashen regions, as able-bodied as somewhat added afresh ~since the 1970’s! in the mid- to far-IR regions. However, Integrating spheres accept been acclimated infrequently for specifically barometer specular materials. This is authentic admitting the actuality that, according to integratingsphere theory, for an ideal sphere, a simple arrangement of two abstracts should aftereffect in the complete reflectance of a specular sample. The acumen for the abridgement of use of Integrating spheres for specular abstracts of reflectance is that complete Integrating spheres are not ideal. The sphere-wall blanket is never a complete Lambertian diffuser, baffles adjy the ablaze administration aural the sphere, and all detectors display some angular dependence. These and added deviations from an ideal apple can acutely affect the accurateness of the apple equations.

Because of the deviations, all spheres accept some amount of contrast of throughput. This agency that the detector arresting will alter as the administration of the reflected or the transmitted ablaze ~and the regions aloft which the ablaze is incident! aural the apple is varied. The aftereffect may be errors in the quantities acquired from the measurements. For this reason, abstracts of reflectance of specular abstracts are usually performed about to a accepted specular standard. When this is done, the regions of the apple bank aloft which the reflected ablaze of the sample and the advertence avalanche usually accept agnate throughputs.

For complete approved ~specular! reflectance measurements, assorted methods, including, V–W, V–N, and goniometer-based methods, are about used. These methods about do not absorb an amalgam sphere. They absorb an ascribe beam, several administering mirrors, and the detector. Some subsets of the mirrors, the sample, and the detector are rotated and translated amid sample and advertence measurements. For the V–N and the goniometer methods, a simple arrangement of the two after-effects produces the complete sample reflectance, admitting for the V–W method, the

square basis is taken.

The primary sources of absurdity in the methods just mentioned are the aftereffect of alignment problems and the spatial contrast of the detector. These problems can calmly advance to errors of several percent or more. With ample accomplishment to accomplish authentic alignment, accomplished after-effects can be accomplished for standards superior samples. However, even in these cases, characteristics of the sample apparent can complete ultimate altitude accuracy. For cellophane materials, ambidextrous appropriately with the transmitted ablaze and barometer the backsurface reflection accurately affectation added difficulties.

An important appliance of Integrating spheres is their use as an averaging accessory for detectors. Because of the advantageous backdrop of the sphere, an averaging sphere’s access anchorage can be both significantly beyond and abundant added spatially compatible than a bald detector. The accommodation fabricated for these improvements is a abasement of the signal-to-noise ratio. The benefits of application the Integrating spheres for added authentic apprehension of ablaze are acclimated in the architecture of

the arrangement and development of the adjustment presented in this paper. The altitude of complete transmittance (t), reflectance (r), and absorptance (a) of specular samples is declared and demonstrated. The inherent problems of apple spatial contrast are affected through accurate use of the symmetries of the apple architecture to authorize symmetries in the altitude geometry. After anecdotic the specifics of the Integrating spheres in Section 2, the added apparatus of the apple arrangement in Section 3, and the complete altitude adjustment in Section 4,

we present the apple assuming measurement.

results for absurdity assay in Section 5. The accomplishment of altitude uncertainties of 0.002 to 0.004

are approved in Section 6 for several accepted IR

materials. Finally, Section 7 contains the altercation of the after-effects with abstracts about the account of the apple adjustment for specular materials.

It is advancing that a approaching analysis of the integrating sphere in which polarized ablaze is acclimated will appearance added throughput aberration with polarization

Besides the about characterless ashen curve, a aciculate anatomy occurs at about 8.5 mm.
This anatomy occurs at the alone amicableness at which the adventure axle from the FTIR axle is signifi-cantly polarized. It is advancing that a approaching analysis of the integrating sphere in which polarized ablaze is acclimated will appearance added throughput aberration with polarization. At the aforementioned time, averaging s- and p-polarized axle abstracts is accepted to annihilate the anatomy apparent at 8.5 mm.
The admeasurement of overfilling the entrance, sample, and advertence ports can be advised by a altitude of an abandoned sample or advertence anchorage in the reflectance mode. Any ablaze advancing through the access anchorage and overfilling the sample ~or reference! anchorage will be abstinent as a reflectance basic with nearunity reflectance of the sphere-wall arena surrounding the port. In addition, any overfilling of the access anchorage in that altitude will aftereffect in some ablaze drop off the rim of the access anchorage into the sphere, consistent aswell in a reflectance basic with top able reflectance. A bend architecture could be acclimated to abate the aftereffect of entranceport overfilling, but it is bigger to be acute to it in adjustment to quantify it. An archetype of the accumulated overfilling-error reflectancemeasurement is apparent in Fig. 5. This was acquired afterwards accurate alignment of the integrating sphere arrangement and the ascribe FTIR beam. The akin of this altitude is lower than has been appear previously.9 The antecedent empty-port altitude was in absurdity because of a subtlety of the FT processing that produced a rectification of the babble in the measurement. This absurdity was alone if the phase-error spectrumobtained in the advertence altitude was acclimated for alteration of the sample empty-port measurement. The actual important sources of absurdity are accompanying to the FTIR spectrometer, detector, electronics,
and FT processing, which are not discussed in detail here. The accumulated altitude absurdity for the transmittance and the reflectance abstracts cover both FTIR-related errors and the integratingsphere arrangement errors. A beeline advanced adjustment of evaluating the altitude accurateness of the arrangement is to analyze altitude after-effects with affected after-effects for the optical backdrop of accepted IR optical materials. Abstracts of a few accepted abstracts are presented in Section 6, and the after-effects are acclimated to accomplish this comparison.

The aboriginal date of this archetypal apropos the ascribe breach design

The actual altitude action is important in free the cosine acknowledgment accurately. The setup, apparent in amount 1, consists of a abroad antecedent or compatible collimated beam, an adapted baffle, acme and azimuth bend rotary stages with the centermost of the sphere's ascribe breach at the centermost of rotation, and a monochromatic/detector arrangement to assay ashen components. Aught degrees acme bend is authentic by absorption of the adventure axle by a mirror, alongside to the access aperture, aback to the source. Aught degrees azimuth is arbitrary, but actuality we accept a lot of accepted analogue for spheres of right-angle geometry (i.e. ascribe and avenue ports are at 90 degrees apart) as "the even absolute the centers of the sphere, access and avenue apertures". Modeling integrating sphere Responses.

Measurement of the assorted combinations of acme angle, azimuth bend and amicableness is an backbreaking assignment acute abounding hours or canticle of effort. If the spheres acknowledgment could be accurately modeled and absolute experimentally alone at adapted points, again an abundant map of the cosine acknowledgment could be generated with basal resources. Moreover, if the cosine acknowledgment is affected from concrete characteristics of the sphere, again modification of those characteristics to advance acknowledgment will be an invaluable architecture aid.

The aboriginal date of this archetypal apropos the ascribe breach design. It is a adage to say that if ablaze entering the integrating sphere is not cosine abased again little can be done central the integrating sphere to compensate.

However, this is absolutely what happens in a lot of accepted designs. A lot of spheres are fabricated as just that i.e. spherical, and again coated on the central with several millimeters of cogitating material. This agency that two apertures now exist: one in the aboriginal integrating sphere and one at the central of the coating. Also, the array of the integrating sphere walls and any accessories about the ascribe breach can

contribute added apertures. When because the integrating sphere acknowledgment due to ascribe perturbing, they can be advised as a alternation of circles whose centers move about to one addition as apparent in amount 2. By artful the bright breach breadth about to that at aught acme angle, the attenuation

due to ascribe perturbing at anniversary acme bend can be evaluated. Once the ablaze is central the integrating sphere it should be chip to abolish all directional effects. However, back ablaze can as well escape from the ascribe breach and the bend subtended from area the axle hits the integrating sphere to the ascribe breach as well varies with angle; we may apprehend a addition from these losses to affect the all-embracing cosine acknowledgment of the sphere. To archetypal this aftereffect as artlessly as possible, several justifiable

Assumptions are made.

Light acuteness abstinent on a even at a specific area is alleged illuminance

Light Level:
Light acuteness abstinent on a even at a specific area is alleged illuminance. Illuminance is abstinent in footcandles, which are workplane lumens per aboveboard foot. You can admeasurement illuminance application a ablaze beat amid on the plan apparent area tasks are performed. Application simple addition and manufacturers' photometric data, you can adumbrate illuminance for a authentic space. (Lux is the metric assemblage for illuminance, abstinent in lumens per aboveboard meter. To catechumen footcandles to lux, accumulate footcandles by 10.76).
Efficacy:
A admeasurement of the beaming ability of a beaming flux, bidding in lumens per watt as the caliber of the absolute beaming alteration by the absolute flux. For daylighting, this is the caliber of arresting alteration adventure on a apparent to beaming alteration on that surface. For electric sources, this is the caliber of the absolute beaming alteration emitted by the absolute lamp ability input.
Efficacy of a Ablaze Source:
The absolute ablaze achievement of a ablaze antecedent disconnected by the absolute ability input. Efficacy is bidding in lumens per Watt.
Watt:
The assemblage of barometer electrical power. Watts does not chronicle to the ablaze achievement level. It defines the amount of activity burning by an electrical accessory if it is in operation. The activity amount of operating an electrical accessory is affected as its wattage time in hours of use. In single-phase circuits, it is accompanying to volts and amps by the formula: Volts x Amps x Ability Factor (PF) = Watts. (Note: For AC circuits, PF have to be included).
Kilowatt Hour (kWh) Formula:
The admeasurement of electrical activity from which electricity announcement is determined. For example, a 100-Watt ball operated for 1000 hours would absorb 100 kilowatt hours (100 Watts x 1000 hours = 100 kWh). At a announcement amount of $0.10/kWh, this ball would amount $10.00 (100 kWh x $0.10/kWh) to accomplish over 1000 hours.
Source: Ablaze Resource.com, Ablaze Research Center, Ablaze Board, IES Lighting Handbook, 5th Edition

It as well can be acclimated in a added ambit demography in annual the ashen absorption curve.

The integrating sphere is an optical component. They are usually acclimated with an array of detectors for the absolute ablaze achievement of a lamp measurement. There is abounding alternation of sphere in the market, although their capital action accepts not change back they are advised by German, there is as well too abounding artifact to choose. Today, I’ll acquaint a integrating spheres which I anticipate are good.

The BaSO4-lamination is able-bodied able and amount acute for the arresting ashen range. There are 3 standards of it and you can see them below.

I. accessible diameters: 10 - 500 mm

Reflex ion: > 96%

Spectral range: 1100 - 20 000 nm

Above 1000 nm a gold argent integrating sphere can be used. The ability is in the repeatability of the broadcast property, as the archetypal aureate burnish is not appropriate in this case. Depending on this admeasurements and all-important broadcast property, the gold will be added active or through exhaustion evaporating.

II. Accessible diameters: 10 - 1000 mm

Reflex ion: > 99%

Spectral range: 180 - 2500 nm

Above 250 mm bore the semi scarves will be apprenticed with bendable aluminum plates. Up to 250 mm bore we comminute the integrating spheres out of an aluminum block. The PTFE is an optimum band-aid for beachcomber breadth amid 180 nm until 2500 nm. The minimum array is 8mm. Depending on the size, the integrating sphere is formed out of a block, or a metal sphere will be coated with PTFE plates. It can be acclimated in ultra violet range, in the arresting ambit and aswell in the abreast bittersweet range.

III. Accessible diameters: 100 - 3000 mm

Reflex ion: > 90%

Spectral range: 300 - 1300 nm

Our bark needs to be printed in at atomic 20 layers. Therefore we get an about absolute broadcast absorption apart from the beachcomber breadth in the arresting ashen range. Our appropriate photometer bark can be sprayed on about all basal materials. It as well can be acclimated in a added ambit demography in annual the ashen absorption curve.

The integrating spheres have 5 ports: input port with 1.5 inch series male flange, 1.0 Inch sample port, in-line with input port, detector port with 1.5 inch series male flange, 1.0 inch specular exclusion/inclusion port (for light trap or plug)

Reflectance and transmittance spheres are 8 inch interior diameter integrating sphere. The integrating spheres have 5 ports: input port with 1.5 inch series male flange, 1.0 Inch sample port, in-line with input port, detector port with 1.5 inch series male flange, 1.0 inch specular exclusion/inclusion port (for light trap or plug). Additional 2.0 inch port at North Pole for center mounted samples or comparison measurement technique. The 70679 and 70682 are for diffuse hemispherical reflectance and total transmittance and measurement of specular using a 8/D geometry (8 degree beam incidence/Diffuse collection). The 70679 is good for the VIS-NIR regions and the 70682 is good for UV-VIR-NIR (Note the ID of the 70682 is ~7.0”).

The spring loading allows you to quickly insert and remove the sample and the 70496 White Spectral Calibration Disk. Light, which is reflected from the sample strikes the port and is turned 8 degrees to the specular exclusion port. A reflectance sample holder with 0.5 inch (13 mm) deep cell, 1 inch (25 mm) diameter holds the sample at 8° to the beam. The holder is spring loaded so that rectangular irregular shapes or square with dimensions up to 2 inches (51 mm) can be held against the sphere wall. The clear aperture is 0.7 inch (18 mm). If a light trap is used in the exclusion port, the specular portion of the sample’s reflectance is subtracted from the measurement. The sample must fill the aperture. If a plug is at the exclusion port, the light is re-captured in the sphere. One extra port plug is included for the north pole port and one exclusion port plug is included with the integrating sphere.

Conversely, if a light trap is used at this port opposite the sample, then the normal transmitted beam is excluded by the trap (normal or diffuse excluded transmittance – allows “haze” characterizations). If a plug is used at the 1.0 inch port opposite the sample (former input port), then all energy is included in the measurement (total transmittance). If the 0° Sample Holder (also included with the 70682 R/T and70679 Spheres) is used at the input beam and the sample port is placed behind the sample port, then you can qualify diffuse, normal or total transmittance of samples.

Measured with the same custom-made integrating sphere

An integrating sphere is an optical sphere internally coated with a reflective material such that light shining into its input port would be complete diffused and uniform by the time it reaches its output port. An integrating sphere has an input port and an output port which is typically mated to a monochromator, sample chamber, or detector. A baffle between the output and input port is optionally available to assure no input light directly reaches the output port without first being diffused by the internal reflective coating. The light source can be placed inside the integrating sphere and sometimes it is used as a sample chamber itself. Due to the many reflective bounces a ray of light has to take before reaching the output port, efficiency is typically around 30%, although this can be more accurately estimated following an approximated equation in the Product Details section. Various internal reflective coatings can also be chosen (depending on spectral region required) and baffles and additional ports can also be ordered. The light that reaches the output port is completely diffused meaning it can reach the output port at any reflective angle.

A multifunctional setup based on the absolute integrating sphere method for measuring luminous flux of light emitting diodes (LEDs) is presented. The total luminous flux in 4pi and 2pi geometries and partial luminous flux with variable cone angle can be measured with the same custom-made integrating sphere. This assumes you can collect all light from all angles as normally you would then have to ratio the solid angle of collection to the light collected at all angles as well. If you are calculating the light that gets collected into a monochromator or detector, use the area of the monochromator or detector slit and not the actual output port area. A complete calibration procedure of the constructed integrating sphere photometer is presented as well as comparison measurements with a goniophotometer. The number of baffles of the sphere and area of ports was minimized. Only one absolute calibration of the integrating sphere photometer is needed for measuring LEDs in all three geometries. The sphere has three ports: an auxiliary port, a detector port, and a main port, located in the same hemisphere. The main port is used for the calibration of the sphere as well as for the LED under test. The spatial nonuniformity correction is needed only for LEDs with low directivity or having significant minor beams. The other hemisphere is free of ports. The expanded uncertainty (k=2) for the measurement setup varies between 4.6% and 1.2% depending on the measurement color, geometry, and the angular spread of the LED light beam.

A hole or "port" in the integrating sphere allows this uniform illumination to be used in an optical system

An integrating sphere is a hollow spherical shell coated on the inside with a highly reflecting diffuse coating. It is available with light traps, port reducers, 0°/8° sample adapters, sample holders and detector mounts. The integrating sphere produces illumination that has extremely uniform irradiance and radiance. A good working model of an integrating sphere is to consider the port to be a hole in a wall, and, at a totally arbitrary distance behind it, another wall of infinite extent and radiance. A hole or "port" in the integrating sphere allows this uniform illumination to be used in an optical system.

The projected solid angle from any point on a sphere to any element of area on the integrating sphere is the same, regardless of location. This fact combined with the diffuse coating and the multiple reflections cause any light introduced into the sphere to produce uniform radiance of and irradiance on the wall of the sphere. The irradiance at the wall of an integrating sphere is incident from a full hemisphere. The radiance at the exit of an integrating sphere extends to a full hemisphere (π projected steradians). The specular component may be included or excluded in the measurement, by the use of a trap or reflectance piece at the relevant port.

Bentham is a company which manufactures a range of integrating spheres for measuring diffuse transmission and reflection. The following part is writing about brief introduction fof two products.

The DTR6 or DTR4 is its product of integrating spheres, coupled with a monochromatic source and detection electronics, allow the determination of the diffuse transmittance and diffuse reflectance of a sample. The monochromatic probe is imaged onto the place of the port appropriate to the measured reflectance, transmittance or quantity. In the case of reflectance, the sample is placed at the reflectance port. In the case of diffuse transmittance, the sample is placed at the transmittance port, the integrating sphere collects all light transmitted into the hemisphere behind the sample.

According to this principle-the integrating sphere collects the scattered light

The good news is that this problem can be solved. Optical absorption, used to assess the concentration of dissolved matter, could be measured through a standard spectrometer arrangement using an input light source and a detector behind the sample. According to this principle-the integrating sphere collects the scattered light and keeps it within the measurement system; the light bounces around the cavity and will eventually contribute to the detected signal-researchers find a method to solve the difficulty. Researchers at North West Water (Warrington, England) have developed a method that overcomes both problems. In the technique, the water flows in an unconstrained stream through an integrating sphere. Within the integrating sphere, optical absorption is measured independent of scattering and this combination of scattering-independent and window-free absorption measurement offers a highly reliable industrial instrument.

Another difficulty arises is the sample also contains particles and bubbles. The only practical restriction is that the input beam makes at least one reflection off the surface of the sphere before reaching the detector; if not, the directly transmitted light would dominate the detected power. It is possible to avoid this interference by making the measurement in an integrating sphere. Scattering from these contribute to the reduction in the light reaching the detector. The light loss through scattering out of the beam path is indistinguishable from absorption in a simple system.

The integrating sphere is an optical instrument. You can find this measurement is so good for anything, like it doesn’t have any weakness. But in a drinking-water treatment plant, it is important to measure both dissolved materials and particles to ensure that the water meets quality standards. Many dissolved materials can be detected by their optical absorption; however, absorption measurement is made difficult by interference from scattering caused by particles. In addition, the cuvette windows of a standard measurement system are often fouled, which reduces instrument reliability.

The optical radiation leaving the integrating sphere

The primary radiation source can be located either in front of the source's entrance port or inside the integrating sphere. In the latter case, only the optical radiation that entering the sphere is relevant for the sphere's internal radiation distribution. As long as we restrict ourselves to those regions which are thus only illuminated by reflections at other of the inner surface and are shielded from direct irradiation by the primary source, the theory of the ideal integrating sphere leads to two important conclusions. The two important conclusions are shown below:

On the one hand, radiance reflected by a region of the sphere's inner surface shielded from direct illumination is independent from the specific location where the reflection occurs and constant in its directional distribution. Thus, the optical radiation leaving the sphere is characterized by existence distributions and homogenous radiance as the integrating sphere's exit port can be used as an ideal Lambert Ian source. This property becomes extremely important when a sphere is used as a standard calibration source.

On the other hand, irradiance of the sphere's inner surface is proportional to the total radiant power either entering the sphere through its entrance port or emitted by a source inside the sphere. Directional and geometrical distribution of the primary source’s radiation does not influence irradiance levels as long as direct illumination of the respective location is prevented. This property becomes extremely important when an integrating sphere is used as the input optical element of a detector for radiant power.

Integrating sphere is a very omnipotent optical element, which are designed to achieve homogenous distribution of optical radiation by means of multiple Lambert Ian reflections at the integrating sphere's inner surface. And it consists of the power meter, the might meter, the connecting box and the ballast. The power meter is used to check the lamp’s power usage. The light meter shows the light level being measured inside the sphere. The connection box is used to connect the ballast to the lamp inside the integrating sphere. At the final, the ballast can’t be in the sphere because of the interference with the light reading. But it is also important to operate nom incandescent lamps. 

Confirming the accurate lack of wavelength dependence in the responsively of the integrating sphere

Using a spreadsheet, this is an example, the responsively at 5 degree intervals in both azimuth and zenith angles was calculated for this sphere. It is easily seen that if this integrating sphere were used for sunlight measurements, with the baffle facing South, negligible cosine errors would be prospective for all results where the zenith angle was less than 75 degrees. Some points near the baffle are some 2%-3% different for calculated and measured responses. This is probably to be the result of multiple localized reflections, each of which looses light through the entrance port, before total randomization within the sphere is achieved. These localized multiple reflection effects, although calculable, are offer little significant improvement in accuracy and beyond the scope of this simple model. Measurements on this sphere, in 15 degree zenith angle steps, at 90 degree and 0 degree azimuth verify that the calculated values of the response are pinpoint. The measured response was determined at wavelengths of 800nm, 700nm, 600nm, 500nm, 400nm and 300nm for all angles. No differences beyond normal experimental error were seen, confirming the accurate lack of wavelength dependence in the responsively of the integrating sphere.

Integrating sphere can be almost perfect devices when designed properly, that means giving highly accurate cosine response at all wavelengths. The integrating sphere response can be estimated precisely from relative simple formulae on a spreadsheet program, as confirmed by actual measurements. In addition, full 3D characterization is possible by calculation, providing detail to the generally incomplete data and enabling components to be optimized provided by some manufacturers. Utility designs can benefit from this modeling, and providing refinements in critical areas. A basic example, the Young & Schneider design, is commercially available from Optioned Laboratories, Inc and makes use of all of the optimization features.

The simple design ideas were used in integrating spheres of four inch and six inch diameter, modeling, and manufacturing. Since the results are close to ideal, they are best expressed as error relative to ideal cosine response. The sphere design, including exit attachments and mounting flanges for a dome window, had been shown is pictures, but not here. Measurements of the cosine response on both two types of integrating spheres agreed well with predictions, and the results are presented for the 6 inch sphere. 

Effective systems have been built that incorporate integrating spheres with detector in the standard averaging mode

The development of a device for absolute measurement of repentance, transmittance, and absorptions of secular samples and the bonnets of using the integrating sphere for more accurate detection of light are used in the design. The method is demonstrated in the case of mirror characterization and IR windows. The ability to measure both reentrance and transmittance in the same geometry is used to quantify directly the total measurement error for nonabsorbent spectral regions, thus also obtaining reliable uncertainty values for results outside these regions.

On careful study and consideration, it can be observed that use of the integrating sphere significantly enabling the levels of accuracy demonstrated in this paper, reduces several important sources of measurement error. These error sources include detector–interferometer and sample– detector introjections, detector spatial no uniformity, detector nonlinearity, and sample–beam geometry interaction （defection, beam deviation, and focus shift）

The integrating sphere system is not suitable for high-sample-throughput applications. For these applications, such instruments can be calibrated with transfer standard samples that are characterized with the sphere system. In turn, other instrumentation designed for fast relative measurements can be used. This approach allows us to improve the accuracy of measurements which made on all our FTS instrumentation, including those designed for variable incidence-angle characterization and variable sample temperature, not directly feasible with the sphere system.

Effective systems have been built that incorporate integrating spheres with detector in the standard averaging mode. For accurate characterization of secular samples, direct mounting onto the sphere is not an absolute necessary. However, there are at least two important advantages of mounting the sample directly onto the sphere. Both of these relate to the characterization of no ideal samples. The first is that this design can measure samples that are not perfectly secular, but that also exhibit some degree of scatter. The second is that one can better handle the worst samples and allow for the greatest amount of focus shift, distortion, deviation, and beam defection. 

Our Engineer and Our Europe Customer

Refer to: http://www.lisungroup.com/blog/training-and-installation-in-turkey-italy-and-portugal/

November seems a special and exciting month for Lisun Electronics Inc the date of Nov.2, Lisun’s engineer James Peng was on his first flight to Turkey and began his two-week technical support for the customers in Turkey,Italy and Portugal.

The three companies are Genel Elektrik Aydinlatma San. Tic. As in Turkey, Pro Light Srl in Italy and CWJ.Componentes S.A.in Portugal. Both the Turkish and Italian customers have purchased Spectrophotometer Integrating Sphere Test System (LPCE-1) [http://www.lisungroup.com/product-id-198.html] and Rotation Luminaire Goniophotometer (LSG-1800) [http://www.lisungroup.com/product-id-241.html]. The Portuguese customer has purchased Rotation Luminaire Goniophotometer (LSG-1800).

Lisun’s engineer James Peng has received a warm welcome from the customers. The detail and professional technical support for the training and installation of the instruments has impressed the customers a lot. Lisun Electronics Inc has also won a high praise and positive feedback for its great service. The Turkish customer said this technical support from Lisun Electronics Inc is even better than most of the world famous companies.

The following pictures show that our engineer James Peng was doing his technical support for the training and installation of Spectrophotometer & Integrating Sphere Test System (LPCE-1) and Rotation Luminaire Goniophotometer (LSG-1800).

Spectrophotometer & Integrating Sphere Test System (LPCE-1): This system is suitable for photometric and colorimetric measurement, such as Energy-saving lamp, Fluorescent lamp, HID lamp (high voltage sodium lamp and high voltage mercury lamp), CCFL and LED test. The measured data meets the requirements of CIE and IES_LM-79 for the measurement of photometry and colorimetry.

Rotation Luminaire Goniophotometer (LSG-1800): LSG-1800 Goniophotometric system is an automatic goniophotometric measurement system for measuring photometric parameters of luminaires, such as LED road lighting fixture, room lighting fixture and projecting lighting fixture. The measured data meets IES standard format and can be applied for lighting design by lighting design software. The measurement system fully satisfy the requirement of lighting design work. LSG-1800B Goniophotometer system is an update version of LSG-1800. The LSG-1800B has a constant temperature detector, and use luminous intensity standard lamp to calibrate the system. Lisun develop a new software to run LSG-1800B.

The basic principle of operation is that light enters the integrating sphere through the sample port, goes through multiple reflections and is scattered uniformly around the interior of the sphere

Integrating sphere is a general function as a light collector. The collected light can be used as a diffuse illumination source or a measurement source. The measurement principle is based on direct illumination and indirect reflection. The basic principle of operation is that light enters the integrating sphere through the sample port, goes through multiple reflections and is scattered uniformly around the interior of the sphere. In the Avantes line of integrated spheres ,the spheres are mostly used as measurement source. The detection fiber optics are SMA-coupled to the port at the side of the sphere which is viewing illumination on a baffle, independent of the angular properties of the light at the sample port.

The reflection version is used to measure total integrated reflectance of a surface, as well as for color measurement and fluorescence spectroscopy. The inside of the integrating sphere is made out of highly reflective diffuse material; that gives a light diffuse reflection (>96 %) over a wide wavelength range (250-2500 nm).  A special gloss-trap is available for the AvaSphere-50-REFL reflection sphere to exclude specular reflection in the measurement. A light source may be connected to the 8 degree SMA-connector port through a fiber optic bundle to make the integrating sphere an ideal uniform light source. This option needs to be ordered together with the sphere. In case specular reflection needs to be included, a white reflective part can be mounted in the position of the gloss trap. 

The irradiance version of the integrating sphere can be used to measure light sources (Laser, LED, and Halogen Lamps). For the irradiance measurements of LED's a special adapter was developed to be connected to the AvaSphere-50-IRRAD. The reflection sphere has an additional SMA- connector port at 8 degrees, for direct illumination, coupling the light into sphere through a fiber and a COL-UV/VIS collimating lens, connected to a light source. The adapter can hold 3, 5 and 8 mm LED's in the correct and reproducible position inside the sphere. The AvaSphere integrating sphere family can be delivered with an active diameter of 30, 50 or 80 mm and an SMA port at 90 degrees for irradiance and reflection measurements. The AvaSphere-30 has a sample port diameter of 6 mm, the AvaSphere-50 10 mm sample port and  15 mm for the 80 mm diameter sphere. All sample ports are knife-edge, this ensures 180 degree field of view of the sample port.