final prototype with adaptor

we were working on compatibility of our prototype.

finally we reached by using converter and adapter.

following picture is the finished prototype of radiation detector

finishing the detector

we are trying to finish our detector with built in dc/dc converter and a adaptor for portability,
we are still working on fiber optics, there may be a possibility to interact this detector with fiber and radiation in turn.

RADIATION DETECTOR

In order to detect the light intensity, we started our task in investigating photo-diodes. after we received enough data and components,fabricated the circuit which is shown below.

fiber optics

- Optical fiber (or "fiber optic") refers to the medium and the technology associated with the transmission of information as light pulses along a glass or plastic strand or fiber. Optical fiber carries much more information than conventional copper wire and is in general not subject to electromagnetic interference and the need to retransmit signals. Most telephone company long-distance lines are now made of optical fiber. Transmission over an optical fiber cable requires repeaters at distance intervals. The glass fiber requires more protection within an outer cable than copper. For these reasons and because the installation of any new cabling is labor-intensive, few communities have installed optical fiber cables from the phone company's branch office to local customers (known as local loops). A type of fiber known as single mode fiber is used for longer distances; multimode fiber is used for shorter distances [1].



What are Fiber Optics?

Fiber optics (optical fibers) are long, thin strands of very pure glass about the diameter of a human hair. They are arranged in bundles called optical cables and used to transmit light signals over long distances.

If you look closely at a single optical fiber, you will see that it has the following parts:

* Core - Thin glass center of the fiber where the light travels
* Cladding - Outer optical material surrounding the core that reflects the light back into the core
* Buffer coating - Plastic coating that protects the fiber from damage and moisture

Hundreds or thousands of these optical fibers are arranged in bundles in optical cables. The bundles are protected by the cable's outer covering, called a jacket.

Optical fibers come in two types:

* Single-mode fibers
* Multi-mode fibers

See Tpub.com: Mode Theory for a good explanation.

Single-mode fibers have small cores (about 3.5 x 10-4 inches or 9 microns in diameter) and transmit infrared laser light (wavelength = 1,300 to 1,550 nanometers). Multi-mode fibers have larger cores (about 2.5 x 10-3 inches or 62.5 microns in diameter) and transmit infrared light (wavelength = 850 to 1,300 nm) from light-emitting diodes (LEDs).

Some optical fibers can be made from plastic. These fibers have a large core (0.04 inches or 1 mm diameter) and transmit visible red light (wavelength = 650 nm) from LEDs[2].


references:
[1]http://searchtelecom.techtarget.com/sDefinition/0,,sid103_gci212716,00.html
[2]http://electronics.howstuffworks.com/fiber-optic1.htm

spectrometer

A spectrometer is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum. The variable measured is most often the light's intensity but could also, for instance, be the polarization state. The independent variable is usually the wavelength of the light. A spectrometer is used in spectroscopy for producing spectral lines and measuring their wavelengths and intensities.In general, any particular instrument will operate over a small portion of this total range because of the different techniques used to measure different portions of the spectrum. Below optical frequencies (that is, at microwave and radio frequencies), the spectrum analyzer is a closely related electronic device[1].

References
1.http://en.wikipedia.org/wiki/Spectrometer

filters and monochromator

Optical filters: generally, belong to one of two categories.
the absorptive filter,
the interference or dichroic filters.
Optical filters selectively transmits light having certain properties (often, a particular range of wavelengths, that is, range of colours of light), while blocking the remainder.In astronomy, optical filters can be used to eliminate light from the Sun or from a star much brighter than the target object[1].


In our project we use filters in order to select the radiation with particular wavelength that is used by solar cell from the available spectrum of light source which is equal to that of sun's spectrum.


A monochromator is an optical device that transmits a mechanically selectable narrow band of wavelengths of light or other radiation chosen from a wider range of wavelengths available at the input[2].
Selecting Wavelengths is to isolate a wavelength of choice—and get it out of the monochromator—is to adjust the position of “the rainbow” so that a desired wavelength passes through the slit and the undesired wavelengths hit the edges of the slit and the inside wall of the monochromator around the slit and are blocked. This
is the reason why many monochromators are painted black inside so that light that strikes the walls of the monochromator is absorbed instead of reflecting around inside and possibly escaping through the exit slit. This fine adjustment, of which wavelengths fall where in the exit plane, is accomplished by slightly—very slightly—adjusting the position of the grating. In modern instruments, this is controlled by a servomotor controlled by a computer. The monochromator can be calibrated by
using a lamp with a well defined spectral line and adjusting the grating position until that line comes out of the exit slit. The grating’s position is then set to “display” that known wavelength. In some instruments this is done
automatically[3].


references:
1.http://en.wikipedia.org/wiki/Filter_(optics)
2.http://en.wikipedia.org/wiki/Monochromator
3.http://www.shsu.edu/~chm_tgc/primers/pdf/mono.pdf

light matter interaction

Interaction of light takes in many ways like:
absorption and emission of photons
Rayleigh scattering
refraction
fluorescence
resonance fluorescence etc
these are all appear to be different but closely related[1].
Atomic excitation and de-excitation is seen in the presence of photon as shown below[2].


(2) Light Scattering
An isolated atom scatters light because the electric field of the incident light wave forces the electrons in the atom to oscillate back and forth about their equilibrium position. By the laws of electromagnetism, when a charge changes its velocity, it emits radiation. Light is emitted uniformly in all directions in the plane ⊥ to oscillation, but decreases in amplitude as the viewing angle shifts away from that plane[3]

Measaurement of brightness of light is possible by caluclating the heat like power per unit area or by measuring the increased heat in black body which is exposed to light, one can meaasure the brightness of light[4].
(The light energy is being converted to heat energy, and the amount of heat energy absorbed in a given amount of time can be related to the power absorbed, using the known heat capacity of the object. More practical devices for measuring light intensity, such as the light meters built into some cameras, are based on the conversion of light into electrical energy, but these meters have to be calibrated somehow against heat measurements. )

references:
1.http://elchem.kaist.ac.kr/vt/chem-ed/light/light-ma.htm
2.http://csep10.phys.utk.edu/astr162/lect/light/molecular.html
3.www.its.caltech.edu/~ch24/lecture2324_2004.pdf
4.http://www.vias.org/physics/bk5_01_03.html

Scientific Visit to Manufacturer

we visited the company on 18th november at 14:00pm.

Our scientific visit to Absolicon Company was very useful and important. A small tour in the company makes us understand a lot of information about the product manufacture of Absolicon X10.

The Absolicon X10 combines many products like (Solar thermal panel, Photovoltaic Panel, Solar Tracker, PLC/Solar Heat Controller, Support Structure) into one product to get low cost with high efficiency and easy installation.

Concerning to the X10, It uses Double Solar Technology™ (DST) which is a technology that has been developed and perfected by Absolicon since 2002.

Simply the idea behind the DST is to combine a Photovoltaic and Thermal Concentrator (CPVT) into one product,

How it works

The sun’s rays hit the solar collector that focuses and thereby concentrates the sunlight ten times on the receiver in the middle of the collector. On the outside of the receiver, special Photovoltaic cells are mounted that can withstand high concentration. The Photovoltaic cells in turn heat up, and in order to keep the cells at optimal production temperatures, the system adjusts the flow of the fluid inside the receiver to cool off the cells, thus producing both electricity and thermal heat.

They have an environment problem which that they dont test their products in some seasons in Sweden that the sun dose not shine, so it is a good reason to build an artificial sun simulator to test and to reduce cost of shipment to test their product in sunny places.

The Company manager was very nice person which welcome us a lot and encourage us to continue our work and to find new ideas that’s help us to build compacq artificial sun simulator, and he gave us some idea about what should be our work.

Experience from the Company:

Looking for Artificial Sun simulator that gives the spectrum of sun and the intensity 20 times to that of sun. This is very useful for finishing the concentrated solar cell simulation with out waiting for sun radiation.

Artificial Sun simulator:

This equipment consists of light sources made of halogen or xenon or argon etc, whose output has the sun spectra,

The other major part of the setup is power supply, which must have the feedback(photo detector) that gives constant output.

Heart of the setup:

Here the complex part comes that is, we need to built a carriage in between the solarcell and light sources.

The work of this carriage(that holds electronic circuit) is to take care of the homogenity on solar cell to avoid the ageing problem of the lights in thir operation. Carriage must take care of the intensity coming from the light to give the solar cell a constant output, so that the simulation goes perfect on every inch of the soalar cell.

The arrangement for artificial sun simulator can be possible in 3 levels, carriage in second level in between light source which is mounted on solar cell. This carriage must move all over the solar cell set and detect the light coming from the source and gives the feedback to powersupply and the light setup in order to get the constant output from solar cell when simulates.

First Stage of our project

As we mentioned in our earlier post that the lamp is the major or heart of the design,we search on different available sources of light required to our design.

we are looking on light sources that is cheap as well as best in terms of spectral distribution.we found Iwaski Xenon arc Lamp having the spectral density same that of the sun's spectra and the cost is almost cheap.




Next we switched to reflectors:

Here we found the ellipse shaped reflector which could be used in our project.

References:
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=1412
http://www.soslightbulbs.com/uxl75xe-ushio-xenon-lamp.aspx

Literature Survey on Sun Simulators

We started investigating on available artificial sun simulators, the following information has got from the survey.

Construction of Sun simulator:
1.Lamp
This Lamp must contain the spectra close to that of sun, and
Intensity much higher than natural sun.
2.Reflector:
The arrangement of reflector must be in the form of ellipse in order to concentrate the beam of light at the focal point.
3.Power Sources:
Power supply must have the stable output, which is possible with the help of photo detector in feedback.

This is just a start of our project Sun Simulators for concentrated solar cells

Introduction to Solar cells

solar cells are used for the generation of electrical energy i.e voltage by using photon energy from sun according to the principle called photovoltaic effect. These cells are also used for generating heat energy.

Solar cells are generally made of semiconducting materials such as silicon, galliumarsanide(GaAs) etc.
we need an impure silicon solar cell for the conversion of light to voltage, in order to have the structural imbalance. This imbalance leads to stable bonding with the result of giving output as a electrical parameter, this is explained clearly in below fig. below.

But our interest is not on working of solar cell but on a device that works like natural sun


Reference:
http://science.howstuffworks.com/solar-cell6.htm

who are we

We are the students from mid-sweden university in sundsvall studying international maters program in electronic design and sensor technology,

We
1.Atamian Hagop
2.Bejugam Santosh Kumar
3.Khalid makeen
4.Mohammad Haja Shariff

are working on a Applied sensor technology project i.e. Sun simulator for concentrated solar cell under the supervision of Hailu Metaferia.