- Email: [email protected]
The new neutron reflectometer NERO
ARTICLE IN PRESS
Physica B 385–386 (2006) 1167–1169 www.elsevier.com/locate/physb
The new neutron reflectometer NERO D. Solina, D. Lott, U. Tietze, O. Frank, V. Leiner, A. Schreyer GKSS Forschungszentrum GmbH, Max-Planck Str. 1,Geesthacht D-21502, Germany
Abstract The year 2005 saw the opening of the new NEutron ReflectOmeter (NERO) at the GKSS research centre in Geesthacht, Germany for the investigation of magnetic and non-magnetic systems as well as soft matter nano-structures. NERO operates with a monochromatic beam of neutrons of wavelength 0.433 nm with a resolution better than 2%. An angular range of 201o2yo1001 allows for both reflectometry and high-angle diffraction measurements to be made. NERO has both a position-sensitive detector and a pencil detector installed for flexibility when making specular and diffuse measurements. NERO has been designed to accommodate heavy-sample environments such as cryo-furnaces and various kinds of magnets. Polarization analysis is available for the investigation of magnetic nano-structures. A supermirror stack with a wide angular-acceptance range will be available in 2006 for time-efficient measurements of magnetic diffuse reflectivity. Further information and proposal forms can be obtained online at http//:genf.gkss.de. r 2006 Elsevier B.V. All rights reserved. Keywords: Reflectometer; Cold neutrons; Polarization analysis; Diffuse scattering; Thin films
1. Introduction Specular neutron reflectometry is an established technique for the study of magnetic thin films [1,2] and softmatter materials [3]. Recent years have seen a diversity in samples studied which include laterally structured magnetic films in the micron to nanometre scale [4,5]. In this case polarized diffuse scattering can play a strong role in understanding the magnetic behavior of these structures. With the continuing strides made in the field of thin films and structured magnetic materials there is an ever increasing need for instrumentation that can accommodate the needs for the study of these films. This paper will give a short description of the new NEutron ReflectOmeter, NERO (Fig. 1), that came online in the year 2005 at Geesthacht Neutron Facility (GeNF). 2. Description of NERO NERO replaces TOREMA, a standard reflectometer at GeNF which was limited in scan range to about 51 in 2y. In comparison NERO covers the range of 201p2yp1001, Corresponding author. Tel.: +49 4152 87 1373; fax: +49 4152 87 1338.
E-mail address: [email protected] (D. Solina). 0921-4526/$ - see front matter r 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.physb.2006.05.401
allowing it to operate as both a reflectometer and diffractometer. It is situated on a cold-neutron guide at GeNF’s research reactor FRG-1. A pyrolitic graphite monochromator has been used to give a 0.433 nm monochromatized beam of neutrons with wavelength resolution of better than 2%. NERO can be used in both polarized and unpolarized modes. The polarizer and analyzer can be inserted automatically by the user via software commands. The polarizer and analyzer are both transmission-type supermirrors. The slit system on NERO is also automated, allowing for remote control of beam width and acceptance angle during measurements. NERO has a horizontal scattering geometry, thus it requires samples to be oriented vertically. Silicon cells can be used for studying liquid interfaces. The sample stage is adaptable and can accommodate heavy-sample environments such as a cryo-furnace and various kinds of magnets. Available upon request are a 0.9 T magnet and cryostats over a temperature range of about 3–475 K. NERO has been equipped with both a pencil detector for fast specular measurements and a 2-D positionsensitive detector, allowing for the collection of specular and diffuse data. The 2-D detector has an
ARTICLE IN PRESS D. Solina et al. / Physica B 385–386 (2006) 1167–1169
1168
Submitted to Elsevier Science Neutrons control unit
monochromator
shielding polariser flipper 1
Li-shutter
analyser
Slit 1
pencilcounter
slit 3
collimation tube
Slit 2 monitor
NG-1
beamcatcher
flipper 2 2-arm
PSD
Fig. 1. Schematic diagram of NERO showing various instrument components.
All components (excluding flippers) are controlled via LABVIEW. The user interface has been designed to allow simple programming of alignment, scan modes and measurement. Data can be viewed and manipulated as data is collected. All collected data and manipulated data is saved in an easy to view ascii format. Reflectivities over 5 orders of magnitude can be measured quite easily with room for further improvement (see. Fig. 2).
100
Normalized Reflectivity
10-1
10-2
10-3
3. Summary
10-4
10-5 0.0
0.1
0.2 Qz [Å-1]
0.3
0.4
Fig. 2. Specular neutron reflectivity pattern obtained for a Fe/Cr multilayer with 60 2.8 nm bilayers. Open circles—original data, line— footprint-corrected data.
NERO is characterized by its versatility in that it can operate in both reflection and diffraction modes. It can operate in both polarized and un-polarized modes. It also allows for the study of diffuse scattering over a wide range of angles with a sample environment that can accommodate heavy equipment such as magnets and cryostats.
4. Access to NERO efficiency of approximately 60% with a sensitive area of 250 mm 250 mm and resolution of 3 mm. The readout is by charge division. A supermirror stack will be available in 2006 for time efficient measurements of magnetic diffuse reflectivity.
NERO is open to national and international users from universities and other research institutes at no cost. Industrial applications are welcome at a negotiable cost. Proposals are accepted throughout the year and forms can be obtained online at http://genf.gkss.de.
ARTICLE IN PRESS D. Solina et al. / Physica B 385–386 (2006) 1167–1169
Acknowledgements [2]
The authors would like to give special thanks to M. Pauls for making the detector and Th. Krist for the polarizers.
[3]
References
[4]
[1] M.R. Fitzsimmons, S.D. Baden, J.A. Borcher, G.P. Felcher, J.K. Furdyn, A. Hoffman, J.B. Kortright, I.K. Schuller, T.C. Schulthess,
[5]
1169
S.K. Sinha, M.F. Toney, D. Weller, S. Wolf, J. Magn. Magn. Mater. 271 (2004) 103. A. Schreyer, T. Schmitte, R. Siebrecht, P. Bo¨deker, H. Zabel, S.H. Lee, R.W. Erwin, C.F. Majkrzak, J. Kwo, M. Hong, J. Appl. Phys. 87 (2000) 5443. J. Webster, S. Langridge, Curr. Opin. Colloid Interface Sci. 4 (1999) 186. K. Theis-Bro¨hl, T. Schmitte, V. Leiner, H. Zabel, K. Rott, H. Bru¨ckl, J. McCord, Phys. Rev. B 67 (2003) 184415. M. Pannetier, F. Ott, C. Fermon, Y. Samson, Physica B 335 (2003) 54.
Physica B 385–386 (2006) 1167–1169 www.elsevier.com/locate/physb
The new neutron reflectometer NERO D. Solina, D. Lott, U. Tietze, O. Frank, V. Leiner, A. Schreyer GKSS Forschungszentrum GmbH, Max-Planck Str. 1,Geesthacht D-21502, Germany
Abstract The year 2005 saw the opening of the new NEutron ReflectOmeter (NERO) at the GKSS research centre in Geesthacht, Germany for the investigation of magnetic and non-magnetic systems as well as soft matter nano-structures. NERO operates with a monochromatic beam of neutrons of wavelength 0.433 nm with a resolution better than 2%. An angular range of 201o2yo1001 allows for both reflectometry and high-angle diffraction measurements to be made. NERO has both a position-sensitive detector and a pencil detector installed for flexibility when making specular and diffuse measurements. NERO has been designed to accommodate heavy-sample environments such as cryo-furnaces and various kinds of magnets. Polarization analysis is available for the investigation of magnetic nano-structures. A supermirror stack with a wide angular-acceptance range will be available in 2006 for time-efficient measurements of magnetic diffuse reflectivity. Further information and proposal forms can be obtained online at http//:genf.gkss.de. r 2006 Elsevier B.V. All rights reserved. Keywords: Reflectometer; Cold neutrons; Polarization analysis; Diffuse scattering; Thin films
1. Introduction Specular neutron reflectometry is an established technique for the study of magnetic thin films [1,2] and softmatter materials [3]. Recent years have seen a diversity in samples studied which include laterally structured magnetic films in the micron to nanometre scale [4,5]. In this case polarized diffuse scattering can play a strong role in understanding the magnetic behavior of these structures. With the continuing strides made in the field of thin films and structured magnetic materials there is an ever increasing need for instrumentation that can accommodate the needs for the study of these films. This paper will give a short description of the new NEutron ReflectOmeter, NERO (Fig. 1), that came online in the year 2005 at Geesthacht Neutron Facility (GeNF). 2. Description of NERO NERO replaces TOREMA, a standard reflectometer at GeNF which was limited in scan range to about 51 in 2y. In comparison NERO covers the range of 201p2yp1001, Corresponding author. Tel.: +49 4152 87 1373; fax: +49 4152 87 1338.
E-mail address: [email protected] (D. Solina). 0921-4526/$ - see front matter r 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.physb.2006.05.401
allowing it to operate as both a reflectometer and diffractometer. It is situated on a cold-neutron guide at GeNF’s research reactor FRG-1. A pyrolitic graphite monochromator has been used to give a 0.433 nm monochromatized beam of neutrons with wavelength resolution of better than 2%. NERO can be used in both polarized and unpolarized modes. The polarizer and analyzer can be inserted automatically by the user via software commands. The polarizer and analyzer are both transmission-type supermirrors. The slit system on NERO is also automated, allowing for remote control of beam width and acceptance angle during measurements. NERO has a horizontal scattering geometry, thus it requires samples to be oriented vertically. Silicon cells can be used for studying liquid interfaces. The sample stage is adaptable and can accommodate heavy-sample environments such as a cryo-furnace and various kinds of magnets. Available upon request are a 0.9 T magnet and cryostats over a temperature range of about 3–475 K. NERO has been equipped with both a pencil detector for fast specular measurements and a 2-D positionsensitive detector, allowing for the collection of specular and diffuse data. The 2-D detector has an
ARTICLE IN PRESS D. Solina et al. / Physica B 385–386 (2006) 1167–1169
1168
Submitted to Elsevier Science Neutrons control unit
monochromator
shielding polariser flipper 1
Li-shutter
analyser
Slit 1
pencilcounter
slit 3
collimation tube
Slit 2 monitor
NG-1
beamcatcher
flipper 2 2-arm
PSD
Fig. 1. Schematic diagram of NERO showing various instrument components.
All components (excluding flippers) are controlled via LABVIEW. The user interface has been designed to allow simple programming of alignment, scan modes and measurement. Data can be viewed and manipulated as data is collected. All collected data and manipulated data is saved in an easy to view ascii format. Reflectivities over 5 orders of magnitude can be measured quite easily with room for further improvement (see. Fig. 2).
100
Normalized Reflectivity
10-1
10-2
10-3
3. Summary
10-4
10-5 0.0
0.1
0.2 Qz [Å-1]
0.3
0.4
Fig. 2. Specular neutron reflectivity pattern obtained for a Fe/Cr multilayer with 60 2.8 nm bilayers. Open circles—original data, line— footprint-corrected data.
NERO is characterized by its versatility in that it can operate in both reflection and diffraction modes. It can operate in both polarized and un-polarized modes. It also allows for the study of diffuse scattering over a wide range of angles with a sample environment that can accommodate heavy equipment such as magnets and cryostats.
4. Access to NERO efficiency of approximately 60% with a sensitive area of 250 mm 250 mm and resolution of 3 mm. The readout is by charge division. A supermirror stack will be available in 2006 for time efficient measurements of magnetic diffuse reflectivity.
NERO is open to national and international users from universities and other research institutes at no cost. Industrial applications are welcome at a negotiable cost. Proposals are accepted throughout the year and forms can be obtained online at http://genf.gkss.de.
ARTICLE IN PRESS D. Solina et al. / Physica B 385–386 (2006) 1167–1169
Acknowledgements [2]
The authors would like to give special thanks to M. Pauls for making the detector and Th. Krist for the polarizers.
[3]
References
[4]
[1] M.R. Fitzsimmons, S.D. Baden, J.A. Borcher, G.P. Felcher, J.K. Furdyn, A. Hoffman, J.B. Kortright, I.K. Schuller, T.C. Schulthess,
[5]
1169
S.K. Sinha, M.F. Toney, D. Weller, S. Wolf, J. Magn. Magn. Mater. 271 (2004) 103. A. Schreyer, T. Schmitte, R. Siebrecht, P. Bo¨deker, H. Zabel, S.H. Lee, R.W. Erwin, C.F. Majkrzak, J. Kwo, M. Hong, J. Appl. Phys. 87 (2000) 5443. J. Webster, S. Langridge, Curr. Opin. Colloid Interface Sci. 4 (1999) 186. K. Theis-Bro¨hl, T. Schmitte, V. Leiner, H. Zabel, K. Rott, H. Bru¨ckl, J. McCord, Phys. Rev. B 67 (2003) 184415. M. Pannetier, F. Ott, C. Fermon, Y. Samson, Physica B 335 (2003) 54.