A multi-wire beam profile monitor in the AGS Page: 1 of 5
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1997 Particle Accelerator Conf., Vancouver, B.C., Canada,
May 12-16, 1997.
A Multi-wire Beam Profile Monitor in the AGS*
H. Huang , W. Buxton, V. Castillo, J.W.Glenn,
G. Mahler, M. Syphers, W. van Asselt, R.L. Witkover, S.Y. Zhang
Brookhaven National Laboratory, Upton, NY 11973, USA
A multi-wire beam profile monitor which can be used to
directly monitor and control the optical matching between
the Booster and AGS rings has been installed and tested in
the AGS. Placement of a multi-wire monitor directly in the
AGS provides profile measurements taken upon injection
and the first two or more revolutions of the beam. The data
from such measurements can be used to determine the op-
tical properties of the beam transport line leading into the
1 INTRODUCTION 3 M
As the AGS prepares to serve as the injector for RHIC,
monitoring and control of the beam transverse emittances -
will become a major and important topic. Before installing 5"
the multi-wire beam profile monitor, there was no device im "
for directly measuring the optical matching between the ARP
Booster and AGS rings. Previously the only beam profile
measurement device in the AGS was the Ionization Profile Figure 1: The A20 harp wires and corr
Monitor (IPM) . However, the IPM measurement is inte- channels. The Reset, Integrate, and H
grated over a finite time interval and therefore can provide shown for simplicity.
only the average profile over a great many number of turns.
Hence, at injection, the profile obtained with the IPM is the
profile after dilution has occured, instead of the profile as beam pipe. To insert, a 3-way solenoid
delivered by the Booster and BTA (Booster to AGS) beam- is powered allowing 60 psi air to move
line. Placement of a multi-wire monitor in the AGS can turn, moves the harp into the beam path
provide profile measurements taken upon injection and the taken off the solenoid and the air move
first two or more revolutions of the beam. The data from opposite direction (out of the beam p
such measurements can be used to determine the optical close when the plunger reaches the e
properties of the beam transport line leading into the AGS. readbacks indicating position are relay
2 HARDWARE AND ELECTRONICS In the A20 harp electronic system
multi-wires goes to individual gated
Multi-wire profile monitors (harps) have been used in the producing an output voltage. These v
HITL (Heavy Ion Transfer Line) , the LTB (Linac to zontal information and 32 for vertical,
Booster) line and the BTA line . These are commer- pIe and hold) channels which are read
cially produced devices which have proven to be very reli- fed to the control system which prod
able. The newly installed harp built for the AGS is similar beam profiles displayed in the AGS m
to existing units and is located in the A20 straight section There are two main processes going
which is close to the injection into the AGS. process during which the charge is Coll
Fig. I shows the arrangement of the harp wires. Horizon- in ss buin hich the integrating cal
tal beam-profile information is derived from the 64 wires a proportional voltage which is directly
that run vertically and the vertical beam-profile informa- channel; and the scan process during
tion is derived from the 32 wires that run horizontally. The on the 96 MUX channels are sequen
0.1 mm diameter tungsten wires are separated by 2 mm control system.
spacing to cover an area of 13.2 cmx 6.4 cm. The hori- When the A20 harp is inserted in
zontal and vertical wires are mounted on the same plane. charge on the wires bleed off to the ir
The harp is pneumatically inserted to a fixed position in the
_______________The integrating op-amp presents a hi~
'Work performed under the auspices of the U.S. Dept. of Energy and in balancing the charge on the i
A STER -STRIBUTION OF THIS DOCUME
old switches are not
d valve on the harp
a plunger which, in
to extract, power is
es the plunger in the
nd of its travel and
ed to the control sys-
, charge from the
oltages, 64 for hori-
go to 96 MUX (sam-
)ut sequentially, and
uces both transverse
ain control room.
on: the integration
ected from the wires
pacitor is charged to
coupled to a MUX
which the voltages
ally read out to the
the beam path the
gh impedance input
N IS UNUM IT7 '
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Huang, H.; Buxton, W.; Castillo, V. & Glenn, J.W. A multi-wire beam profile monitor in the AGS, article, July 1, 1997; Upton, New York. (https://digital.library.unt.edu/ark:/67531/metadc676598/m1/1/: accessed June 15, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.