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Evaluation of Uncertainty Contributions of Measurement Surface and Number of Microphone Positions in Determination of Sound Power Levels

100%

Bilgic E., Mutaf H., Kirbas C., Sadikoglu E.

Acta Physica Polonica A

2017

vol. 132

issue 3

642-649

Sound power level of a noise source is determined by means of sound pressure level or sound intensity level measurements performed in accordance to relevant ISO standards. The determination of sound power level according to ISO 3744, 3745 and 3746 standards is used for free field or for approximated free field conditions. Kinds of measurement surfaces, enveloping the noise source, number of microphones and their positions over the measurement surface are stated in the applied ISO standard. The effects of measurement surface and number of microphone positions on the determination of sound power level were investigated theoretically. As a measurement surface; hemisphere, parallelepiped rectangular box and cylindrical surfaces were selected. Key and additional microphone positions were taken into account in the calculations as well. Sound pressure levels of a commercially available reference sound source were measured in hemi-anechoic room using FFT with 4 Hz steps and also at 1/1, 1/3, 1/12 and 1/24 octave bands for all surfaces defined in ISO 3744 and 3746 standards. Sound power level, directivity index and uncertainty contributions resulting from measurement surfaces and number of microphone positions were calculated by using data obtained in measurements. In this paper the theoretical and experimental results are presented.

Determination of Pulse Width and Pulse Amplitude Characteristics of Materials Used in Pendulum Type Shock Calibration Device

100%

Bilgic E.

Acta Physica Polonica A

2017

vol. 132

issue 3

857-860

Calibration of shock and vibration transducers is performed by using the methods described in ISO 16063-13 and 16063-22 standards, at primary and secondary levels respectively. At secondary level, the devices, generating mechanical shock, are pendulum shock calibrator, dropball shock calibrator, pneumatically operated piston shock calibrator and Hopkinson bar shock calibrator. The main parameters and requirements of the shock calibrator devices, named here, are also given in ISO 16063-22 standard. Pulse width and pulse amplitude are the important parameters in calibration of the shock and vibration transducers. Pulse width and shape depend on the material properties. In this paper the determination of pulse width and pulse amplitude characteristics of materials used in pendulum type shock calibration device, designed in TUBİTAK UME, is presented.

Time Calibration of the J-PET Detector

64%

Skurzok M., Silarski M., Alfs D., Białas P., Shivani, Curceanu C., Czerwiński E., Dulski K., Gajos A., Głowacz B., Gorgol M., Hiesmayr B., Jasińska B., Kisielewska-Kamińska D., Korcyl G., Kowalski P., Kozik T., Krawczyk N., Krzemień W., Kubicz E., Mohammed M., Pawlik-Niedźwiecka M., Niedźwiecki S., Pałka M., Raczyński L., Raj J., Rudy Z., Sharma N., Sharma S., Shopa R., Wieczorek A., Wiślicki W., Zgardzińska B., Zieliński M., Moskal P.

Acta Physica Polonica A

2017

vol. 132

issue 5

1641-1644

The Jagiellonian positron emission tomograph project carried out in the Institute of Physics of the Jagiellonian University is focused on construction and tests of the first prototype of PET scanner for medical diagnostic which allows for the simultaneous 3D imaging of the whole human body using organic scintillators. The J-PET prototype consists of 192 scintillator strips forming three cylindrical layers which are optimized for the detection of photons from the electron-positron annihilation with high time-and high angular resolutions. In this article we present time calibration and synchronization of the whole J-PET detection system by irradiating each single detection module with a ²²Na source and a small detector providing common reference time for synchronization of all the modules.

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Evaluation of Uncertainty Contributions of Measurement Surface and Number of Microphone Positions in Determination of Sound Power Levels

Determination of Pulse Width and Pulse Amplitude Characteristics of Materials Used in Pendulum Type Shock Calibration Device

Time Calibration of the J-PET Detector