Recent observations on the APS storage ring using synchrotron radiation monitors. Page: 1 of 5
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RECENT OBSERVATIONS ON THE APS STORAGE RING USING
SYNCHROTRON RADIATION MONITORS*
The Advanced Pho
and our synchrotron
noticeably in the past,
mation from two sepa
dispersive point in the
nostic undulator. Data
transverse beam size
parameters to calculate
tion on the beam emit
dard lattice and a low
4%), and beam positi
measurements of dive
length (- 35 ps), and
the source point image
M. Borland, L. Emery, A. H. Lumpkin, N. Sereno, and B. X. Yang
Advanced Photon Source
Accelerator Systems Division
1~ Argonne National Laboratory
P 2 ~ ~Argonne, IL 60439 USA
2 EXPERIMENTAL BACKGROUND
ton Source (APS) 7-GeV storage ring The APS storage ring diagnostics have been summarized
radiation diagnostics have matured in more detail elsewhere , and the initial OSR diagnos-
year. The monitors now include infor- tics results were described at PAC'95 . The basic acceler-
rate bending-magnet sources (one at a ator parameters for diagnostics are listed in Table 1. The
lattice) as well as a 198-period diag- fundamental rf frequency is 351.9 MHz with a harmonic
logging via EPICS of the observed number of 1296 in the 1104-m-circumference ring. The rev-
is coupled with the measured lattice olution period is 3.68 ps with a minimum bunch spacing of
e emittance on-line as well. Informa- 2.8 ns. Our most used fill patterns include a train of 6 con-
tance (7 t 1 nm rad) in both the stan- secutive bunches (used for rf BPM electronics) and then
Py lattice, the vertical coupling (1 to sets of 25 triplets about 100 ns apart or 22 singlets about
on and jitter are logged. In addition, 150 ns apart. Three source points for synchrotron radiation
ergence, (3 to 7 prad), beam bunch are now imaged: two bending magnets and one insertion
even effects of the moon's gravity on device. The natural emittance baseline is 8.2 nm rad.
position have been performed.
Table 1: Accelerator Parameters for Diagnostics in the
TRODUCTION Storage Ring Baseline Design Lattice
As the Advanced Photon Source (APS) storage ring (SR)
has matured, our diagnostics capabilities using optical syn-
chrotron radiation (OSR) and x-ray synchrotron radiation
(XSR) have also been developed. In the 1997-98 period, we
have supplemented our initial bending magnet source point
imaging lines [1,2] with the recent commissioning of trans-
port lines for a diagnostics undulator and another bending-
magnet source at a zero dispersion point in the lattice.
Within this period, the SR lattice has also been adjusted for
a reduced vertical P value in the straight sections to accom-
modate a small-gap (5 mm) insertion device vacuum cham-
ber in one area of the ring. The tests on vertical coupling
and beam divergence were checked with our full comple-
ment of source points. On-line data logging of the beam's
transverse size and the calculated emittance based on the
measured lattice parameters was done under user condi-
tions. Improvements in the x-ray pinhole camera hardware
and image analysis have allowed the detection of the effects
of the moon's gravity on the SR effective orbit circumfer-
ence. This phenomenon has been previously reported using
a laser polarimeter at the LEP storage ring  and using rf
BPMs  at the APS storage ring.
"Work supported by U.S. Department of Energy. Office of Basic
Energy Sciences, under Contract No. W-31-109-ENG-38.
Energy (GeV) 7
Natural emittance (nm rad) 8.2
rf freq. (MHz) 351.93
Harmonic no. 1296
Mn. bunch spacing (ns) 2.8
Revolution period (ps) 3.68
Design max. single-bunch current (mA) 5
Nominal multibunch current (mA) 100
Bunch length (2a) (ps) 35-100
Transverse beam profiles and bunch lengths have been
measured using both OSR and XSR imaging techniques. In
the case of transverse beam size, the visible light pick-off
mirror is a single Mo surface whose central region is shad-
owed from the intense x-rays by a water-cooled copper
tube. The visible light is transported out of the tunnel to an
optics room. The standard charged-coupled device (CCD)
The submitted manuscript has been created by the University of Chicago as Operator of Argonne National Laboratory ("Argonne") under Contract No. W-31-109-ENG-38
with the U.S. Department of Energy. The U.S. Government retains for itself. and others acting on its behalf, a paid-up, nonexclusive. irrevocable worldwide license in said
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Borland, M. Recent observations on the APS storage ring using synchrotron radiation monitors., article, July 30, 1998; Illinois. (digital.library.unt.edu/ark:/67531/metadc619563/m1/1/: accessed April 24, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.