MARPOS Laboratory Services

Laboratory Setup & Service Fees

We have two main measurement systems:

Positron Annihilation Lifetime Spectroscopy (PALS) as a fast-fast coincidence system

Doppler Broadened Emission Spectroscopy (DBES)

The first measures lifetime of ortho-positronium (o-Ps) as a measure of free volume in materials and the latter measures broadened spectra of annihilation radiation that gives information about free volume hole sizes and chemical defects in materials.

We have also Variable Energy Positron Beam System (VEPOS) to study surfaces and interfaces. We measure depth defect (vacancy and chemical) profile of surfaces changing the positron energy up to 30 keV. We have DBES ready, but we are still working on the lifetime spectroscopy.

MARMARA POZİTRON/POZİTRONYUM LABORATUVARI

For Bulk Materials:

Positronium Annihilation Lifetime Spectroscopy (PALS, PLTAS)

Doppler Broadened Emission Spectroscopy of Positron Annihilation (DBES)

For Films, Coatings, etc. on Variable Energy Positron Beam System:

Doppler Broadened Emission Spectroscopy (DBES)

Laboratory Service Fees

Item Quantity* Fees (Euro)
Each measurement Positron Annihilation Lifetime Spectroscopy for bulk materials 1 400 

Each measurement of Doppler Broadened Emission Spectroscopy (DBES) of Positron Annihilation for bulk materials

1 500

Measurement of Doppler Broadened Emission Spectroscopy (DBES) for each positron energy on Variable Energy Positron Beam System

1 300 
Free volume analysis using the Simha Somcynsky Hole Theory
(PVT data must be supplied)
1 500

*Single measurement and analyzing prices for each sample. If some temperature measurements are requested for the same sample, 40% discount is made for each temperature on the indicated prices.
If the sample is liquid or liquid-like material, then we charge extra 300 Euro for each sample.

Taxes (KDV)  is not included.    

 

Positron Annihilation Lifetime Measurement (PALS)

By using Positron Annihilation Lifetime Spectroscopy, we estimate three lifetimes (possible 4 upon request) and their intensities. These are para-positronium, direct annihilation, and ortho-positronium (o-Ps). Using these information, we calculate free volume hole size and radius values. Additionally, we calculate free volume according to Kobayashi scheme using fv=C I3*vf(τ3).

 

Doppler Broadened Emission Spectroscopy of Positron Annihilation Measurement (DBES)

Using Doppler Broadened Emission Spectroscopy, we calculate 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 as 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.  

 

Free Volume Analysis Using the Simha Somcynsky Hole Theory

Using Simha-Somscynsky hole theory, for a given PVT data in liquid and glassy states as well crystalline, characteristic parameters; mo, c, s, P*, T*, V*, v*, 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, hole fraction as a measure of free volume (free volume fraction) will be calculated and drawn graphs 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.

 

Calculation of additional two different thermodynamic quantities below is required to additional same charge
With available experimental data, some other thermodynamic quatities such as thermal expansion, expandibility,  ... will be calculated. All the information will be tabulated and graphed upon request.

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 with 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 Arts and Sciences Physics Department No: C120  
34722 Kadıköy, İSTANBUL


This page updated by Pozitron/Pozitronyum Araştırma ve Hizmet Laboratuvarı on 09.02.2022 12:05:49

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