Here - PMOD/WRC

wavelength / nm
U180 @ MLS
band width
U49 @ E/ E= 10 -2
BESSY II
photon flux / s -1
MLS
W180 @ MLS
BESSY II
WLS
7T
200 MeV 600 MeV
PTB special
900 MeV 1700 MeV
far IR and IR VIS UV VUV / soft X-rays X-rays
photon energy E / eV
Figure 2: Spectrum of the radiation from MLS and BESSY II.
Instrumentation and tasks
Figure 3 illustrates the planned instrumentation at the MLS,
a list of the beamlines is given in table 2.
The spectral photon flux of synchrotron radiation from
bending magnets can be precisely calculated from
Schwinger’s theory [5], given that all parameters entering
the equation are known. At the MLS, PTB will install
equipment for the measurement of these parameters with
high accuracy. The storage ring parameters taken into
account in the calculation are the electron beam current,
the electron energy, the magnetic induction at the radiation
source point and the vertical beam size and divergence.
The electron energy will be measured by Compton
backscattering of laser photons (beamline 2), the other
parameters will be determined in a similar way as done at
BESSY II [2, 3]. The relative uncertainty in the calculation
of the spectral photon flux will be below 0.04 % for
photon energies below 100 eV and will then gradually
increase for increasing photon energies. For 1000 eV
photons, the relative uncertainty will be 0.17 %.
PTB will use the storage ring as a primary source standard
for the calibration of energy-dispersive detectors (beamline
4) and radiation sources (beamline 5). For these
applications, it is essential that the electron energy and
electron beam current allow adjustment as required by the
current calibration task in order to achieve low relative
uncertainties. In combination with a monochromator beam
line as a source of monochromatic radiation of high
spectral purity, the storage ring is also used for
detector-based radiometry and reflectometry (beamlines 6,
7). IR (beamline 9) and FIR/THz radiation (beamline 8)
will be available for radiometry, photon metrology or
analytics.
Besides bending magnet radiation, highly intense
undulator radiation in the spectral range from the IR to the
EUV will be available for high accuracy radiometry based
on a cryogenic radiometer (beamline 3) or high flux
experiments (beamline 1 and 2).
Figure 3: Planned instrumentation at the MLS.
Table 2: List of planned beamlines and experimental stations at
the MLS
1 deflected undulator radiation
2 direct undulator radiation / IR /
Compton-backscattering
3 UV/VUV monochromator for undulator radiation
4 direct bending magnet radiation
5 UV/VUV monochromator (source calibration)
6 EUV plane-grating monochromator
7 UV/VUV monochromator (detector calibration)
8 FIR/THz beamline
9 IR beamline
10 diagnostics frontend
Summary
The parameters of the MLS, especially the electron beam
current and the electron energy, can be varied in a wide
range in order to create measurement conditions that are
tailor-made for specific calibration tasks. All storage ring
parameters can be precisely measured, which enables PTB
to operate the storage ring as a primary source standard.
Bending magnet radiation with characteristic energies
ranging from 11.6 eV up to 314 eV will be available and
so will be undulator radiation from the IR up to the EUV
spectral region.
The MLS complements the measurement potential
available at BESSY II in the lower energy range and thus
enables PTB to use synchrotron radiation from the THz up
to the hard X-ray region for high-accuracy photon
metrology, especially radiometry.
References
1. Klein, R. et al., Proc. of EPAC04, Lucerne, Switzerland,
2290–2292, 2004.
2. Klein, R., R. Thornagel, G. Ulm, Proc. of EPAC04,
Lucerne, Switzerland, 273–275, 2004.
3. Thornagel, R., et al., Metrologia, 38, 385-389, 2001.
4. Klein, R., et al., Synchrotron Rad. News 15, no. 1, 23-29,
2002.
5. Ulm, G., Metrologia, 40, S101–S106, 2003.
6. Ulm, G., et al., Proc. SPIE, 3444, 610–621, 1998.
7. Ulm, G., et al., Rev. Sci. Instrum., 66, 2244–2247, 1995.
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