Laboratory Setup and Service Fees
We have two main measurement systems:
Positron Annihilation Lifetime Spectroscopy (PALS) as a fast-fast coincidence system
Doppler Broadening Spectroscopy (DBS)
The first measures the lifetime of ortho-positronium (o-Ps) as a measure of free volume in materials, and the latter measures broadened spectra of annihilation radiation that give information about free volume hole sizes and chemical defects in materials.
We also have a Variable Energy Positron Beam System (VEPOS) to study surfaces and interfaces. We measure the depth defect (vacancy and chemical) profile of surfaces, changing the positron energy up to 30 keV. We have DBS ready, but we are still working on the lifetime spectroscopy.
For bulk materials:
Positronium Annihilation Lifetime Spectroscopy (PALS)
Doppler Broadening Spectroscopy of Positron Annihilation (DBS)
For films, coatings, etc. on the Variable Energy Positron Beam System:
Doppler Broadening Spectroscopy (DBS)
Laboratory Service Fees
Item | Quantity | Fees (Euros) |
Each measurement Positron Annihilation Lifetime Spectroscopy (PALS) for bulk materials | 1* | 200 |
Each measurement of Doppler Broadening Spectroscopy (DBS) of Positron Annihilation for bulk materials |
1* | 250 |
Measurement of Doppler Broadening Spectrocopy (DBS) on Variable Energy Positron Beam System for 5 different positron energies. |
1 | 400 |
Free volume analysis using the Simha Somcynsky Hole Theory (PVT data must be supplied.) |
1 | 200 |
*Single measurement and analysis of prices for each sample. If some temperature measurements are requested for the same sample, a 50% discount is made for each temperature on the indicated prices. PALS is limited to 1 million counts. Add 50 euros for each million-count increase. |
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Taxes (KDV) are not included. | ||
Positron Annihilation Lifetime Measurement (PALS) |
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By using Positron Annihilation Lifetime Spectroscopy, we estimate three lifetimes (possible four upon request) and their intensities. These are para-positronium, direct annihilation, and ortho-positronium (o-Ps). Using this information, we calculate the free volume hole size and radius values. Additionally, we calculate free volume according to the Kobayashi scheme using fv=C I3*vf(τ3). |
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Doppler Broadening Spectroscopy (DBS) of Positron Annihilation |
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Using Doppler Broadened Emission Spectroscopy, we calculate the S and W parameters. The S parameter is calculated as the area under the curve in the central (511 keV peak) region as a contribution of lower momentum divided by the total area in the region of interest (ROI). The W parameter is the area under the wing regions as a contribution of higher momentum divided by the total area in the ROI. Both parameters have sensitivity to defect type and concentration in materials. |
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Free Volume Analysis Using the Simha Somcynsky Hole Theory |
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Using Simha-Somscynsky hole theory, for given PVT data in liquid and glassy states as well as crystalline, characteristic parameters mo, c, s, P*, T*, V*, v*, and e* will be calculated and tabulated. The scaled graph of V with respect to P and T or any combination will be drawn upon request. Using these parameters, the hole fraction as a measure of free volume (free volume fraction) will be calculated and graphs drawn with respect to T and P upon request. Additional information can be extracted from the SS theory upon request. In addition to these basic calculations, Tait equations (in forms requested or forms we offer) will be given for PVT scaled data or hole fraction in terms of scaled T and P.
The calculation of the additional two different thermodynamic quantities below is required to add the same charge With available experimental data, some transport properties such as viscosity, ionic conductivity, dielectric relaxation, and diffusion in terms of temperature and pressure can be calculated and will be related to the hole fraction as a measure of free volume. All the information will be tabulated and graphed upon request. |
Contact:
Prof. Dr. Uğur YAHŞİ
E-mail: uyahsi@marmara.edu.tr Phone: +90 (216) 777 3320
Prof. Dr. Cumali TAV
E-mail: ctav@marmara.edu.tr Phone: +90 (216) 777 3307
Address:
Marmara University Göztepe Campus
Faculty of Science, Physics Department Office: GZF-C120
34722 Kadıköy, İSTANBUL
This page updated by Pozitron/Pozitronyum Araştırma ve Hizmet Laboratuvarı on 27.12.2023 17:03:44