Implementation of a CCD detector to dual- broadband ...

1 Implementation of a CCD detector to dual - broadband rotational cars and measurements on N2O Master of Science thesis by Alem Kindeya August 2010 Division of Combustion Physics Department of Physics Lund University ALEM KINDEYA MASTER THESIS REPORT Division of Combustion Physics, Lund University Page 2 2010 ALEM KINDEYA MASTER THESIS REPORT Division of Combustion Physics, Lund University Page 3 2010 Implementation of a CCD detector to dual - broadband rotational cars and measurements on N2O Master of Science thesis Alem Kindeya Division of Combustion Physics Department of Physics Faculty of Engineering LTH LUND UNIVERSITY ALEM KINDEYA MASTER THESIS REPORT Division of Combustion Physics.

2 Lund University Page 4 2010 Alem Kindeya Lund Reports on Combustion physics, LRCP-141 Lund, Sweden, August 2010 Alem Kindeya Division of Combustion Physics Department of physics Faculty of Engineering LTH Lund University 118 S-221 00 Lund, Sweden ALEM KINDEYA MASTER THESIS REPORT Division of Combustion Physics, Lund University Page 5 2010 Abstract The master thesis work involved the Implementation of a CCD detector to a dual - broadband rotational coherent anti-Stokes Raman spectroscopy (DB-RCARS) setup, and temperature measurements on N2O.

3 This included the investigation of seven different setting options of the detector to identify the best possible option of the camera regarding a good precision temperature measurement . Additionally, a theoretical library for N2O at room temperature and atmospheric pressure condition was developed. The spectroscopic constants of the molecule are the inputs of the temperature library. The temperature precision was found to be marginally influenced by the three basic setting options (pre-amplifier, readout rate and binning).

4 This indicates that it is possible to choose any level within these setting options as long as the signal level is high (on the order of thousand of counts). The precision was found to be independent of the binning of pixels in the spectral dimension. The high sensitivity and high capacity output amplifiers gave similar precision, but the signal is around five times stronger for the former amplifier than the later. The threshold intensity above which it is possible to achieve the smallest possible precision for the current CCD camera was identified for full vertical binning mode to be around 1000 counts.

5 The measurements on N2O were made to understand the spectroscopic features of the molecule and try to evaluate its potential for temperature measurement purposes. As a result, the value of temperature precision was found to be better than for N2. Generally, the N2O molecule showed a good potential for temperature measurements at room temperature conditions. ALEM KINDEYA MASTER THESIS REPORT Division of Combustion Physics, Lund University Page 6 2010 ALEM KINDEYA MASTER THESIS REPORT Division of Combustion Physics, Lund University Page 7 2010 Contents Chapter 1: Purpose of the 10 General 10 Chapter 2: Background rotational energy of 12 Laser- based Combustion Diagnostic 13 Chapter 3: Coherent anti-Stokes Raman spectroscopy ( cars ).

6 14 dual - broadband rotational Experimental Setup of rotational 17 Chapter 4: Andor CCD 18 Safe Camera 19 Environmental 20 20 Working principle of CCD 23 Preamplifier 24 Readout 25 26 CCD 27 High Sensitivity (HS) output 27 High Capacity (HC) output 28 Chapter 5: Experimental Implementation of CCD Camera and testing N2O for temperature 41 Chapter 6: Result and 43 detector 43 Pre-amplifier 43 Read-out 47 50 Signal 53 ALEM KINDEYA MASTER THESIS REPORT Division of Combustion Physics, Lund University Page 8 2010 Instrument Influence of intensity on precision and 57 Comparison of FVB and Multi-track 61 measurement on 64 Temperature 64 Chapter 7.

7 Summary and 69 ALEM KINDEYA MASTER THESIS REPORT Division of Combustion Physics, Lund University Page 9 2010 Chapter 1 Introduction The global energy need is expected to increase the coming decades because of many reasons: fast economic growth of some developing countries, expansion of high level facilities in developed countries, the global population increase in developing countries, etc. This energy might come from different sources, but combustion has been the basic sources of energy for many years.

8 People were hugely dependent on combustion through years for heating, cooking and related activities. The dependence of energy from combustion processes is expected to increase for the future as well. This means that combustion processes will continue to be the main source of energy despite it has negative impact to the environment as it causes global warming which is a burning issue this time. Figure [1] shows a prognosis of the global energy need until 2060. Therefore, combustion has to be efficient to generate highest possible energy from certain amount of fuel, and to minimize environmental impact.

9 To make a combustion process very efficient, the process should be understood more clearly on a molecular level. Unfortunately, this is not easy, because, the combustion process is very complicated since it involves many elementary reactions and often has complex fluid flow. To really understand the basic processes, there is a demand for high spatial and temporal resolution measurements. The need for spatial resolution, temporal resolution and the importance for non-intrusive measurement are the main reasons for the development of laser based combustion diagnostic techniques.

10 There are many laser based techniques which can be used for diagnostic purposes as discussed in chapter two. The technique used in the current study is dual - broadband rotational coherent anti-stock Raman spectroscopy (DB-RCARS), which previously has shown to be a good technique for temperature measurements. Nitrogen is usually probed with this technique. Figure : Plot of global energy use as a function of years. The use of organic and fossil fuel is expected to increase at least until 2020 and then remain relatively constant [1].