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September 15th 2009 Olympus technical review at DESY, F.Brinker 1
DORIS storage ring
•Olympus in the IP-region
•Beam optic, changes on the lattice
•Beam dimensions, Target cell
•Synchrotron Radiation
•Beam acceleration, Particle polarity
•Machine studies
September 15th 2009 Olympus technical review at DESY, F.Brinker 2
Geometry of the detector and the IP-region
September 15th 2009 Olympus technical review at DESY, F.Brinker 3
View to the IP-region from outside with ARGUS on the left side
September 15th 2009 Olympus technical review at DESY, F.Brinker 4
Top view with radiation shielding
September 15th 2009 Olympus technical review at DESY, F.Brinker 5
Straight section from the arc to the IP
Vertical scraper
Horizontal scraper
Main source of synchrotron
radiation
beam direction
September 15th 2009 Olympus technical review at DESY, F.Brinker 6
doct3w doct3wBlast (symm.point / at 1.2 m) Emittance at 4.5 GeV 465 nm 438 nm Qx 7.17 7.17 Qz 4.77 5.23 βx 26 m 2.4 m 3.2 m βz 9.7 m 1.5 m 2.6 m Dx -1.3 m -0.5 m
Blast IP Additional quad at ± 7m
New optic with a reduced beam size at the IP :
from σx x σz = 3.7 x 0.7 mm2 to 1.1 x 0.3 mm2
Due to the asymmetry of the detector the target cell is not at the IP but at about 0.75 m
Optical functions at the insertion devices and injection are kept nearly unchanged
September 15th 2009 Olympus technical review at DESY, F.Brinker 7
Energy [GeV] 2.0 2.3 4.5
Max Beam Current [mA] 140
Target cell 27 mm x 9 mm
Beta-x IP < 2.7 m
Beta-z IP < 1.5 m
Lifetime ≈ 0.7 h
Energy acceptance > 0.8%
hor. Emittance [nm] 91 119 440
hor. Dispersion at IP [m] -0.5
hor. beamsize (1) at Target[mm] 0.55 0.63 1.2
vert. Emittance (5% coupl.) [nm] 4.5 6.0 22
vert. beamsize (1) at Target[mm] 0.09 0.11 0.21
energy spread (1) [%] 0.049 0.056 0.11
hor. damping time [ms] 29.0 19.1 2.6
vert. damping time [ms] 27.6 18.1 2.5
long. damping time [ms] 13.5 8.8 1.2
Main
Parameter
September 15th 2009 Olympus technical review at DESY, F.Brinker 8
Horizontal Acceptance and Beam sizes at 4.5 and 2.3 GeV
The acceptance is defined by the existing aperture limitations and limits the extend of any beam halo
0
10
20
30
40
50
60
70
80
90
-40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15
position from IP [m]
[mm
]
Acceptance 20 sigma(4.5 GeV) 20 sigma (2.3 GeV)
September 15th 2009 Olympus technical review at DESY, F.Brinker 9
vertical Acceptance and Beam sizes at 4.5 and 2.3 GeV
0
5
10
15
20
25
-40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15
position from IP [m]
z [m
m]
Acceptance 20 sigma(4.5 GeV) 20 sigma (2.3 GeV)
September 15th 2009 Olympus technical review at DESY, F.Brinker 10
Vacuum system
current position
to be removed
new position
current position
new position
valves
Adapter chambers
September 15th 2009 Olympus technical review at DESY, F.Brinker 11
Synchrotron Radiation [B.Nagorny, A.Schmidt]
Energy [GeV] 2.0 4.45
Power through Target [W] 1.1 23.9
Photons through target [1/sec] 1.4E16 3.0E16
Power on fixed collimator [W] 3.4 76.4
Photon on fixed collimator [1/sec] 4.4E16 9.7E16
Critical energy [keV] 1.56 16.0
About 60% of this could be shielded by the movable scaper stations
September 15th 2009 Olympus technical review at DESY, F.Brinker 12
0
10
20
30
40
50
60
-0.08-0.06-0.04-0.02 0 0.02 0.04 0.06 0.08
-0.04
-0.02
0
0.02
0.04
0 10 20 30 40 50 60
Synchrotron radiation at 4.5 GeV - dipole
W/cm²
Linear power density: 24 W/cm
0 2 4 6 8 -8 -6 -4 -2
4
2
0
-2
-4
x [cm]
y [cm]
September 15th 2009 Olympus technical review at DESY, F.Brinker 13
Injection for DORIS III and PETRA III
For OLYMPUS particle beams with electrons and positrons are needed with energies of 2.0 to 2.3 GeV
The Linac, PIA and DESY are able to deliver both particles.
The energy of the DESY synchrotron varies sinusoidal with a maximum energy of up to 7 GeV
The extraction energy is defined by the peak energy and the timing of the extraction within the energy cycle. Both are variable.
Modifications are needed for fast switching of the magnet polarity of DORIS and the transport.
450 MeV Linac: Gun delivers electrons, which can be converted to positrons after half of the linac
PIA : accumulation of several linac pulses to increase the bunch current
DESY : 12.5 Hz / 7 GeV Synchrotron – a trigger generator allows the extraction at different energies to either Doris or Petra
September 15th 2009 Olympus technical review at DESY, F.Brinker 14
Machine studies on February 7th •Injection into 10 bunches
•Final current 170 mA after 6 minutes
•Varying efficiency – probably due to effects at DESY:
•DESY operated at normal maximum energy of 4.5 GeV
•At 2.3 GeV the beam is not fully damped to its equilibrium emittance
•Possibly beam blow up due to resonances
September 15th 2009 Olympus technical review at DESY, F.Brinker 15
Machine studies on February 7th
Stored beam with good conditions:
• I = 150 mA• Lifetime = 8.5 hours
Not so nice:
Longitudinal beam excitation (oscillation with ~1cm Amplitude)
Limits lifetime at higher currents
maybe increased particle background
September 15th 2009 Olympus technical review at DESY, F.Brinker 16
Machine shift Aug. 3rd
Beam intensity limited to 120 mA in 10 Bunches , long. stable
September 15th 2009 Olympus technical review at DESY, F.Brinker 17
Machine shift Sept. 9th
90%+ injection efficiency , 30 mA injected in 2 min.
September 15th 2009 Olympus technical review at DESY, F.Brinker 18
Sept. 9th, horizontal scraper measurements
2.3GeV, Lifetime dependance on scraper position
-1.5
-1
-0.5
0
0.5
1
1.5
2
0 100 200 300 400 500
scraper position x^2 [mm^2]
log
(L
ife
tim
e[h
])
beam core - gaussian
profile
region of beam halo
halo ends at≈ 19mm
since the horizontal beam size at the IP is about a factor 2 smaller, the beam halo would extend to ± 10 mm from beam center
results are preliminary, the scraper position has to be verified!
September 15th 2009 Olympus technical review at DESY, F.Brinker 19
2.3 GeV, Lifetime dependence on vert. scaper position
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
0 10 20 30 40 50
scraper position z^2 [mm^2]
log
( l
ife
tim
e[h
] )
Sept. 9th, horizontal scraper measurements
beam core - gaussian
profile
region of beam halo
halo ends at≈ 5.5 mm
since the vertical beam size at the IP is about a factor 3 smaller, the beam halo would extend to ± 1.8 mm from beam center
results are preliminary, the scraper position has to be verified!
September 15th 2009 Olympus technical review at DESY, F.Brinker 20
topics for further studies:
• stabilize ejection from synchrotron / improve transfer efficiency
• find optimal working point for tunes
• experiences with second long. feedback amplifier (installation at end of September)
• investigate max. stable beam current (presently 120mA)
• tests at 2.0 GeV
September 15th 2009 Olympus technical review at DESY, F.Brinker 21
Infrastructure
•Detector power supply
•Detector cooling
•Polarity switches
•Kicker pulser
•Preparation of the experimental hall
•Modification of the IP region
•Installation of Olympus
September 15th 2009 Olympus technical review at DESY, F.Brinker 22
Detector power supply
• A 10kV to 480V transformer is available and will be placed outside the experimental hall
• The foundation has to be prepared• The 7000 A power supply from Petra has to be installed
in the hall • The cabling to the transformer (10kV), to the power
supply (2500A, 480V DC) and to the detector (7000A, 225V DC) has to be done mainly by an external company
September 15th 2009 Olympus technical review at DESY, F.Brinker 23
Water cooling of toroid• The capacity of the cooling tower is sufficient• The cooling water circuit to ARGUS is still available• It’s now in use for the cooling of transport line magnets• The capacity of the circuit is sufficient for Olympus after
smaller modifications ( 20 m of new tubes with larger cross section )
• The two installed pumps have to run in parallel • The pressure has to be reduced from 12 bar to 5 bar
Cooling for the moved cavities is still available, the last few meters are missing
Cold water for air conditioning is also available, tubes have to be laid
September 15th 2009 Olympus technical review at DESY, F.Brinker 24
Trans-former
Water cooling
Power-supply
Electronics hutch
September 15th 2009 Olympus technical review at DESY, F.Brinker 25
Polarity switches• There are 46 main magnet power supplies at DORIS and
the transport line• 12 of those are already replaced by bipolar devices• 10 devices with currents below 270A can be modified
with polarity switches from HERA• The remaining 24 devices need new polarity switches,
14 devices for 400A and 10 devices for 800A• Cabinets, controls and cabling have to be done
September 15th 2009 Olympus technical review at DESY, F.Brinker 26
Kicker pulser
• The extraction/injection elements at DESY and DORIS have to be bipolar
• The Septa can be modified accordingly• The Kicker ( 2 DORIS + 1 DESY ) need new power
supplies and new pulsers which would be build at DESY
September 15th 2009 Olympus technical review at DESY, F.Brinker 27
Preparation of the experimental hall
• Part of the hall is in use for an DESY exhibition, these objects will be removed and partly find a new home in HERA hall west
• The ARGUS detector will be disassembled and removed
This work will start soon and should be finished by the end of this year
September 15th 2009 Olympus technical review at DESY, F.Brinker 28
Modification RF-lab
• An RF laboratory for testing of Tesla cavities is placed on the outside of the DORIS ring
• A rectangular region of 2.5 x 9.5 m has to be cut out – Install dust cover– Remove walls – Cut ceiling and floor– Build new walls– Change installations ( crane, electricity, water etc.)
This work can start in summer 2010, when the ongoing work in the laboratory is finished (earlier, if possible)
September 15th 2009 Olympus technical review at DESY, F.Brinker 29
Modification of the IP region (1. shut down in winter 2010/11)
• Move signal cables from IP region ( can be done in advance )
• Remove interlock installations• Remove shielding blocks• Remove accelerator components
– Cavities, vacuum chambers– 4 quadrupoles– Girders
• Install dust cover• Demolition work on parts of concrete
September 15th 2009 Olympus technical review at DESY, F.Brinker 30
Modification of the IP region, cont.
• Build up new shielding• Install new girders/support for experiment vacuum• Put in 6 new quadrupoles• Install vacuum system, including target chamber and
new vacuum valves• Install cavities at the new position• Cabling, water connections• Install modified interlock system• Surveying
September 15th 2009 Olympus technical review at DESY, F.Brinker 31
Installation of Olympus ( 2. shut down in summer 2011 )
• Remove part of shielding• Remove vacuum system between valves• Roll in the detector• Install vacuum chambers• Connect cooling water and electrical power• Rebuild shielding• Surveying• Interlock tests
September 15th 2009 Olympus technical review at DESY, F.Brinker 32
Summary• The space for the detector is still available• Some modifications to the storage ring are necessary – but no
“show-stoppers” are visible• A beam optic has been developed which should work for
synchrotron radiation runs as well as for OLYMPUS• The most time consuming work takes place outside the Doris tunnel
and needs no shutdown time• The modifications of the IP region can be done within 2 shutdown
periods• The infrastructure for the experiment can be provided to a large
extend with available equipement
The effort to realize the experiment is significant, but it’s only a small fraction of what’s already available.