Setup for the crystal purification by the traveling molten zone method. - PowerPoint PPT Presentation

1 / 1
About This Presentation
Title:

Setup for the crystal purification by the traveling molten zone method.

Description:

... raw material/powder is melt and transferred into TMZ setup. ... In the TMZ method the heating ring moves along the tube/ampoule and creates a molten zone-disk. ... – PowerPoint PPT presentation

Number of Views:127
Avg rating:3.0/5.0
Slides: 2
Provided by: sora3
Category:

less

Transcript and Presenter's Notes

Title: Setup for the crystal purification by the traveling molten zone method.


1
Setup for the crystal purification by the
traveling molten zone method. TMZ for XEUS
V. Kozlov1b, M. Leskelä1b, M. Ritala1b, H.
Sipilä2, J. Huovelin1a, H. Kärkkäinen2, E. Kiuru2
and J. Hiltunen2
1aDepartment of Astronomy, University of
Helsinki, Helsinki, Finland 1bDepartment of
Chemistry, University of Helsinki, Helsinki,
Finland 2Metorex International Oy, Espoo, Finland
  • Introduction
  • The XEUS mission is characterised by ambitious
    science goals, which will require substantial
    technological advances in many parallel fields.
    One of such is the search and development of
    compound semiconductors for X-ray and gamma-ray
    detectors. Our preliminary studies on TlBr
    material have showed that the material quality is
    far from perfect. Improved materials are needed
    for the future planetary and astrophysics
    investigations.

LT
Degassing
Tc / M
F
Z
HBr Preparation Drying
F
FC
PM
  • The aim of this work is to construct a traveling
    molten zone (TMZ) setup for the crystal
    purification. TMZ-method is traditionally used in
    semiconductor technology for materials
    purification. The TMZ-instrument has been
    designed by METOREX International and University
    of Helsinki (Department of Chemistry) for the
    rectification of thallium halides under various
    atmospheres. The system consists of two parts
    (see Figure 1)
  • - Preliminary material treatment
  • - TMZ purification

NT
TMZ
M
Tc
Pump
Figure 1. System for the preliminary material
treatment and purification (degassing, TMZ,
vacuum and Tl -fixation).
(Purge) gas system
Vacuum System
  • Preliminary material treatment
  • The preliminary melting allow to avoid the use of
    aggressive atmosphere during prolonged TMZ
    cleaning. During preliminary treatment, water and
    another components adsorbed are removed using
    vacuum or appropriate gas atmosphere and step by
    step heating. After full degassing, the raw
    material/powder is melt and transferred into TMZ
    setup.

Outlet filter
Chemical pump
Filter
Liquid nitrogen trap
Tl-fixation
Flow control
Pressure meter
M
Tc
SM
  • TMZ purification
  • In the TMZ method the heating ring moves along
    the tube/ampoule and creates a molten zone-disk.
    Due to the equilibrium between solid-melt-solid
    phases the trace components are separated and
    collected at opposite sides of the ampoule. The
    rate is controlled from 1mm/h to 1mm/day. Because
    of the different mobility of elements the
    appropriate rate can be chosen according to the
    contamination presented. Higher rates can be used
    for the annealing and lower ones for the single
    crystal growth and re-crystallization. The TMZ
    setup is presented in Figure 2.

Heating control HR supply
Step motor control
valve soft valve
decompressor
Figure 2. TMZ purification setup
  • Status
  • The setup is under the testing and probe running
    in METOREX International Oy.
  • Acknowledgements
  • This work is a part of the consortium High Energy
    Astrophysics and Space Astronomy (HESA) financed
    by the Academy of Finland and the Finnish
    Technology Agency TEKES within the framework of
    the Finnish space research programme ANTARES.
  •  
Write a Comment
User Comments (0)
About PowerShow.com