EPOS consits of several setups

Latest news ( for system description see below):  

22. February 2013: New beam time - preparation for user operation
Beam time in February 2013

27. March 2013: preparation for next beam time (5.-7. April 2013)
Accelerator exit with aperture
2011 Nov. 9th: Photos shown during a small party in our workshop to celebrate the first successful use of MePS at HZDR (Link)
September 2011 - February 2013:
No beam time due to extension of ELBE hall
2011-09-20: Preparation of next beam time (Link)
Sample chamber with Faraday cup
2011-09-26: Successful beam time in September 2011(Link)
Lifetime spectra of low-k layers measured by MePS
2011-06-02: Beam time in begin of June 2011(Link)
One half of the chopper system
2011-06-20: MePS beamtime: test of chopper (Link)
Beam profile measured using a film
Kicker Meeting FZD 12.1.2011- Talk of RKR (Link) 2010-11-11: MePS Beamtime: 2nd test of chopper (Link)
View into open MePS beam line
2010-May-25: Continuation of MePS beamline (Link)
Beamline on MePS
2010-June-03: Beamtime for MePS adjustment (Link)
Beam as scanned over an aperture by the steering coils
2010-March-02: Further built-up of MePS system and test of time structure
top view to the MePS system @ March 2010
2010-April-22: Adjustment of large magnet by 4 Hall probes at beam line

4 Hall probes at beamline
2009-Nov-30: Coil winding around a further bended coil
2010-01-29: GiPS Beamtime - neutron activated Fe-Cr samples were measured
Laser adjustment of beamline in MePS
2009-September-15: First positrons at MePS (Mono-energetic Positron Spectroscopy) @ EPOS!
First positron lifetime spectrum at MePS!
2009-October-29: Further beam time for testing the time structure at MePS and for GiPS development
GiPS setup using NaI instead of Ge detector for coincidence
2009-February: Beam adjustment by electrons
February 2009: Beam adjustment by electrons
2009-March-4: Final preparations for initial operation of positron converter
Pt moderator in front of electrostatic extraction lens
2008-October: 22-Na source installed for test purposes
Positron source capsule in front of extraction lense
2008-December: We successfully tried GiPS (Gamma-induced Positron Spectroscopy)
our first GiPS spectrum: pure, annealed iron
2008-July-15: We got the electrons through the beam line!

Electron beam spot visible at end of beam line...
August 2008: we are starting the beamline in the lab
 Beamline in lab starts growing...
2008-July-02: We (RKR, Marco Jungmann, Maik Butterling, and Nicki Hinsche) continued to build up the lead screening

Further buildup of the Pb screening...
2008-July-09: We installed an electron beam source for the easy adjustment of the magnetic beam guidance system

The electron beam source in place to check the magnetic beam guidance...
Wolfgang Anwand is now member of the EPOS construction team

Acceleration of 1 ton of lead is sometimes impossible ...
We started the erection of the concrete radiation screening

The final concrete block gets its position...
2008-April-23: Vacuum system sufficiently tight. Lead castle is growing
Lead castle growing around positron converter in Cave 111b.
2008-April-30: This time we mounted additional steering coils in the cable tunnel.- a very difficult work only for sportive students

Nicki laying in the entrance hole for the cable tunnel in Lab111d
2008-April-02: Converter chamber removed for welding

Converter chamber is being removed to be welded in Workshop due to a leak.
2008-April-10: Converter chamber is still leaking after additional welding (p-end=8E-7 mbar). We decided to built a new chamber from stainless steel. We will use an alloy which resists neutron activation (Alloy 1.4006 without Ni, which would form 60-Co). However, the leak of the current chamber is not so bad, so that we can continue to test the beam guidance system by electrons and positrons from a 22-Na source. Moreover, we started the wiring for the magnetic guidance and steering system.

Andreas conects cables from the cave to the steering power supplies.
2008-March-26: some vacuum problems solved, but still one weld leaking...

Inner stand for the top Pb layer is installed

Miniworkshop "Die Positronenannihilation in der modernen Werkstoff-Forschung" FZD Dresden - Rossendorf, 2. April 2008

2008-Febr-27: Vacuum system at converter chamber is installed

First lead bricks of the radiation shield in position
2008-March-3: Problems with cutting lead bricks
Marco attempts to cut Pb bricks, but saw is not suitable
2008-January-22: Welding of water pipes for beam dump
Dump is elevated for welding
2008-Febr-14: Mounting of converter chamber

Converter chamber mounted to the beam dump in Cave 111b
2007-12-19: Leak testing - finally the system was tight
Leaktesting of beamline through cable tunnel
2008-01-15: Beamdump and converter chamber mounted for the first time

Converter & Dump mounted for the first time in Cave 111b
  • 2007-11-13: Transport of most vacuum parts to FZD by two lorries

  • June ... October 2007: test setup for vacuum testing at Univ. Halle (photo 1 und 2)

  • June 2006: Stability test of beam dump rack performed

  • November 2005: Talks about EPOS given at HIPOS Workshop in Bergen /Netherlands (here and here)

  • November 2005: Al-Beamdump ready for use

  • October 2005: First tests for buncher electronics

  • September 2005: computer-driven current sources for correction coils ready

  • August 2005: First parts are done in the workshop (Buncher)

  • Second User meeting EPOS-04 at Halle University (1./2. March 2004)

  • Talk about EPOS given at Hahn-Meitner-Institute Berlin in September 2003

  • August 2003: Construction of Laboratory started!

  • See the oral contributions as PDF and some photos of EPOS-02 meeting in Rossendorf!

2007-11-27: Start of assembling the EPOS vacuum system in Cave 111b - Beam line through cable tunnel is installed

Mounting the EPOS beam line trough cable tunnel


The intense positron source EPOS is under construction as an external research facility of the “Center of Materials Research - CMAT” of the University Halle at the ELBE Radiation Source at Research Center Rossendorf. It will be dedicated to materials research. The unique time structure of ELBE (short electron bunches in cw mode – 5ns, 13 MHz) will directly be used to form a monoenergetic positron beam. Positron lifetime spectroscopy will become the most important experiment. A large counting rate will be possible by a multi-detector system. Moreover, Coincidence Doppler Broadening Spectroscopy and AMOC will be possible. The detector system shall be completely digital in order to have almost no tuning elements. This allows the remote control of the system. The EPOS system will be operated as a user-dedicated facility. The lab itself is now under construction, and the design work for the positron beam itself started too.


Concept of EPOS

EPOS will make use of the unique features of the intense 40 MeV electron beam of ELBE (up to 40 kW). Positrons will be generated by pair production and are guided from the well shielded inner cave (room 111b) through a tunnel to the outer positron laboratory (111d). The above mentioned unique feature is the time structure (bunch width about 5ps; repetition rate 13 MHz) which makes ELBE to an ideal host for a bunched positron beam.

EPOS Scheme

Scheme of EPOS.


Top View Drawing of Cave 111b.

 Top View Drawing

The Positron Lab

This is the location of the EPOS lab (enlarged view)


EPOS homepage

University Halle

Department of Physics at Univ. Halle

CMAT at Univ. Halle

Research Center Dresden

ELBE Radiation Source at Rossendorf

Positron Laboratory Halle

personal home page of Reinhard Krause-Rehberg

Halle, 28-Mrz-13