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The infrared line IR4 at the NSLS
Nuclear Instruments and Methods in Physics Research A246 (1986) 165-167 North-Holland, Amsterdam
THE INFRARED
165
L I N E IR4 A T T H E N S L S
G w y n P. W I L L I A M S ,
P e t e r Z. T A K A C S , R o g e r W. K L A F F K Y
a n d M. S H L E I F E R
National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973, USA
We describe the infrared beamline which is being constructed at the NSLS. In order to maintain the high brightness at long wavelengths (up to 1 mm) where diffraction becomes a problem, a high aperture extraction port is used. Problems of cooling of the first mirror will also be discussed. Large off-axis ellipsoids are used to bring the beam to a secondary focus on a mezzanine floor before entering a monochromator or being collimated for an interferometer.
1. Introduction
3. Beamline details
We have previously analyzed and discussed the attractive characteristics of synchrotron radiation (SR) [1] and the National Synchrotron Light Source in particular [2] in the infrared region. The brightness is between 2 and 3 orders of magnitude higher than that of a black body. The total radiated flux is, however, less than that of a blackbody so that the advantages of synchrotron radiation depend on the application. Full advantage of the enhanced brightness is taken in experiments such as surface vibrational spectroscopy where the sample acceptance matches the beam emittance. The NSLS is implementing an infrared facility to take advantage of the uniqueness of the source and in this paper we describe the design details of this beamline which is designated IR4.
A schematic (not to scale) of the beamline is shown in fig. 2. The geometry was determined by three main requirements: (1) The first mirror should be able to be retracted and replaced, (2) clearing neighboring existing beamline front ends, and (3) delivering the beam to a platform above existing beamlines for extra floor space. Requirement (1) is satisfied by having the mirror pair M1, M2 on a manipulator which allows M1 to be retracted through a gate valve. M2 is also a plane mirror 550 m m above M1 and also at 45 °. It measures 115 x 163 mm. The M1, M2 "periscope" sends the beam back along in the " u p s t r e a m " direction of the electron beam to M3, which is an ellipsoidal mirror 145 × 205 mm, situated 314 m m from M2. M3 deflects the beam horizontally by 90 ° (p-polarization) onto the experimental floor where it is intercepted by plane mirror M4 880 m m away and of dimension 72 x 102 mm. M4 deflects the beam vertically to M5 which is 820 m m away and is a focusing mirror identical to M3. Thus, an image of the source with a magnification of 0.9 is produced (primary focus) between M4 and M5 which is remagnified to give a 1 : 1 image (secondary focus) at the platform.
2. Extraction The large natural radiation opening angle for synchrotron radiation in the infrared, combined with diffraction considerations lead to the requirement of a large vertical aperture of - 100 mrads in the machine. The limit to the vertical aperture is provided by the dipole coils and therefore the closer the source is to the edge of these coils, the larger the angle. The best position then turns out to be as shown in fig. 1, that is immediately downstream of the dipole. A slot in the chamber 40 m m high by 290 mm long allows us to extract 90 × 90 mrad. The beam is then deflected vertically upwards by a plane mirror M1 of dimension 63 m m x 90 m m and located 661 mm from the source. The power loading on this mirror is - 5 0 0 W / c m 2 which requires careful consideration of its cooling [3]. The mirror will be silicon carbide, edge cooled by means of clamped on water-cooled copper blocks. 0168-9002/86/$03.50 © Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)
4. Summary
The beamline described produces an f l 0 1 : 1 image of the source at the platform. The useful wavelength range is from 300 A to > 1 mm. It is envisaged that at the platform the beam will pass through a window and then enter a commercial interferometer. Details of this and the experimental chamber are under consideration. It is anticipated that the extraction chamber will be installed sometime in 1986 followed by construction of the beamline. lI(a). INTEGRATED BEAM LINES
G.P. Williams et al. / The infrared line 1R4
166
ELECTRON BEAM VACUUM CHAMBER ,. . . . .
~' ~ t ;"-' t
/ t
DIPOLE MAGNET COILS
~
I
r F
I I
/ /¢ //
/
/
/
/
/ ,' , / / ,/ /
I.R. RADIATION
J
j/
/
5 ° PORT
22 ° PORT
33.5 ° PORT INFRA-RED
TO ION PUMP
Fig. 1. Artist's impression of the beam extraction for the NSLS IR4 beamline.
~-ACTUATOR \,~ ?~OR Box \'\\\ ~ ~-MIRRORMANIPULATOR ,,,, ,,, ", r-MIRRORM5 ' ~
",, ~" ", ", I IIR, ',
,/ ..... ~MIRROR M2
-rATE,,A.,,E
EX,TCHAMBER
/~
j--MIRROR MANIPULATOR ~MIRRORM~
~'~"-'.
~-.EWPORT ;ABLE ' --,NTE.FEROM~TER
%--",~ ",
@MIRROR M4 ---
I I
MIRROR MANIPULATOR
" ~-PLATFO~
/'"
~
I ~
~'-
I
Fig. 2. Schematic view of the NSLS IR4 beamline (not to scale). M3, M5 are focussing ellipsoids.
G.P. Williams et al. / The infrared line IR4
We are indebted to our colleagues, notably Y, Chabal, F. H o f f m a n n and D. Moller who have participated in many discussions prior to and during the design stages of this project. This work performed under the auspices of the U.S. Department of Energy under contract DE-AC0276CH00016.
167
References [1] W.D. Duncan and G.P. Williams, Appl. Optics 22 (1983) 2914. [2] G.P. Williams, Nucl. Instr. and Meth. 195 (1982) 383. [3] R. Alforque et al., these Proceedings (Synchrotron Radiation Instrumentation, Stanford, 1985) Nucl. Instr. and Meth. A246 (1986) 168.
II(a). INTEGRATED BEAM LINES
THE INFRARED
165
L I N E IR4 A T T H E N S L S
G w y n P. W I L L I A M S ,
P e t e r Z. T A K A C S , R o g e r W. K L A F F K Y
a n d M. S H L E I F E R
National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973, USA
We describe the infrared beamline which is being constructed at the NSLS. In order to maintain the high brightness at long wavelengths (up to 1 mm) where diffraction becomes a problem, a high aperture extraction port is used. Problems of cooling of the first mirror will also be discussed. Large off-axis ellipsoids are used to bring the beam to a secondary focus on a mezzanine floor before entering a monochromator or being collimated for an interferometer.
1. Introduction
3. Beamline details
We have previously analyzed and discussed the attractive characteristics of synchrotron radiation (SR) [1] and the National Synchrotron Light Source in particular [2] in the infrared region. The brightness is between 2 and 3 orders of magnitude higher than that of a black body. The total radiated flux is, however, less than that of a blackbody so that the advantages of synchrotron radiation depend on the application. Full advantage of the enhanced brightness is taken in experiments such as surface vibrational spectroscopy where the sample acceptance matches the beam emittance. The NSLS is implementing an infrared facility to take advantage of the uniqueness of the source and in this paper we describe the design details of this beamline which is designated IR4.
A schematic (not to scale) of the beamline is shown in fig. 2. The geometry was determined by three main requirements: (1) The first mirror should be able to be retracted and replaced, (2) clearing neighboring existing beamline front ends, and (3) delivering the beam to a platform above existing beamlines for extra floor space. Requirement (1) is satisfied by having the mirror pair M1, M2 on a manipulator which allows M1 to be retracted through a gate valve. M2 is also a plane mirror 550 m m above M1 and also at 45 °. It measures 115 x 163 mm. The M1, M2 "periscope" sends the beam back along in the " u p s t r e a m " direction of the electron beam to M3, which is an ellipsoidal mirror 145 × 205 mm, situated 314 m m from M2. M3 deflects the beam horizontally by 90 ° (p-polarization) onto the experimental floor where it is intercepted by plane mirror M4 880 m m away and of dimension 72 x 102 mm. M4 deflects the beam vertically to M5 which is 820 m m away and is a focusing mirror identical to M3. Thus, an image of the source with a magnification of 0.9 is produced (primary focus) between M4 and M5 which is remagnified to give a 1 : 1 image (secondary focus) at the platform.
2. Extraction The large natural radiation opening angle for synchrotron radiation in the infrared, combined with diffraction considerations lead to the requirement of a large vertical aperture of - 100 mrads in the machine. The limit to the vertical aperture is provided by the dipole coils and therefore the closer the source is to the edge of these coils, the larger the angle. The best position then turns out to be as shown in fig. 1, that is immediately downstream of the dipole. A slot in the chamber 40 m m high by 290 mm long allows us to extract 90 × 90 mrad. The beam is then deflected vertically upwards by a plane mirror M1 of dimension 63 m m x 90 m m and located 661 mm from the source. The power loading on this mirror is - 5 0 0 W / c m 2 which requires careful consideration of its cooling [3]. The mirror will be silicon carbide, edge cooled by means of clamped on water-cooled copper blocks. 0168-9002/86/$03.50 © Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)
4. Summary
The beamline described produces an f l 0 1 : 1 image of the source at the platform. The useful wavelength range is from 300 A to > 1 mm. It is envisaged that at the platform the beam will pass through a window and then enter a commercial interferometer. Details of this and the experimental chamber are under consideration. It is anticipated that the extraction chamber will be installed sometime in 1986 followed by construction of the beamline. lI(a). INTEGRATED BEAM LINES
G.P. Williams et al. / The infrared line 1R4
166
ELECTRON BEAM VACUUM CHAMBER ,. . . . .
~' ~ t ;"-' t
/ t
DIPOLE MAGNET COILS
~
I
r F
I I
/ /¢ //
/
/
/
/
/ ,' , / / ,/ /
I.R. RADIATION
J
j/
/
5 ° PORT
22 ° PORT
33.5 ° PORT INFRA-RED
TO ION PUMP
Fig. 1. Artist's impression of the beam extraction for the NSLS IR4 beamline.
~-ACTUATOR \,~ ?~OR Box \'\\\ ~ ~-MIRRORMANIPULATOR ,,,, ,,, ", r-MIRRORM5 ' ~
",, ~" ", ", I IIR, ',
,/ ..... ~MIRROR M2
-rATE,,A.,,E
EX,TCHAMBER
/~
j--MIRROR MANIPULATOR ~MIRRORM~
~'~"-'.
~-.EWPORT ;ABLE ' --,NTE.FEROM~TER
%--",~ ",
@MIRROR M4 ---
I I
MIRROR MANIPULATOR
" ~-PLATFO~
/'"
~
I ~
~'-
I
Fig. 2. Schematic view of the NSLS IR4 beamline (not to scale). M3, M5 are focussing ellipsoids.
G.P. Williams et al. / The infrared line IR4
We are indebted to our colleagues, notably Y, Chabal, F. H o f f m a n n and D. Moller who have participated in many discussions prior to and during the design stages of this project. This work performed under the auspices of the U.S. Department of Energy under contract DE-AC0276CH00016.
167
References [1] W.D. Duncan and G.P. Williams, Appl. Optics 22 (1983) 2914. [2] G.P. Williams, Nucl. Instr. and Meth. 195 (1982) 383. [3] R. Alforque et al., these Proceedings (Synchrotron Radiation Instrumentation, Stanford, 1985) Nucl. Instr. and Meth. A246 (1986) 168.
II(a). INTEGRATED BEAM LINES