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Prepare DORIS for particle physics again
F.Brinker, DESY, March 31st 2008
•Injector chain to Doris and Petra
•Situation at the IP-region
•Beam optic
•Work laying ahead
•Operational constrains
Injection for DORIS and PETRA
Mode 1 (e+) :
DORIS needs new injection every 8 hours
PETRA runs in top up mode – one new bunch every
1-30 seconds, depending on current and lifetime
Mode 2 (e- or e+):
DORIS and PETRA are running in top-up mode
1 bunch to PETRA every 1-30 sec
1 bunch to DORIS every 30-60 sec
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
doct3w doct3wBlast Emittance 465 nm 438 nm Qx 7.17 7.17 Qz 4.77 5.23 βx 26 m 2.4 m βz 9.7 m 1.5 m Dx -1.3 m -0.45 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
Topic DORIS shutdown Necessary ?
Components to buy
Remove Argus No - Revise rails and container No ? Install Blast No ? Electric power for detector No Low voltage distribution
(230V/50Hz ?) Magnet power supply (reuse existing?)
Water cooling of detector No Water pumps Cooling pipes
Air conditioning No Air conditioning Construction of vacuum parts No ? Move cavities from IP to SL 26m Yes Pipes, cables Modification of vacuum system Yes 2 valves
additional UHV pumps ? Modification of magnet girder Yes - Installation of 2 Quadrupoles Yes Magnet PS. ( reuse existing?) Installation of PS polarity switches Yes Remotely controlled polarity
switches relocate cables and water pipes from IP Yes Pipes, cables Remove concrete blocks from IP-region Yes - Shift detector in the ring Yes - Build up radiation shielding Yes ? Safety ( interlock, emergency stop, fire detector, gas detector )
Yes Detectors, cables, interfaces
Tasks for installing the detector :
Operational issues
• e+/e- operation of LINAC, PIA and DESY is possible – switching takes about 5 min. ( … on the long term DORIS and Petra should run with electrons only )
• For a fast change of the polarity of the DORIS magnets additional power supply switches have to be installed.
• The change of the particle type in DORIS should be possible within one hour.
• Due to the lifetime reduction and energy changes a parallel operation with Hasylab is not possible.
• Due to the frequent changes of the particle type also a common operation with Petra III is excluded ( Top-up mode at Petra!)
• The particle optic in DORIS is matched to keep the optical functions nearly unchanged at all wiggler positions – therefore it has not to be changed for the synchrotron radiation runs. The target cell can stay in the ring.
Summary
• The space for a detector like Blast is still available• Some modifications (and investments) are necessary – but no
“show-stoppers” are visible• An optic has been developed which should work for synchrotron
radiation runs as well as high energy runs• The most time consuming work can be done outside the Doris
tunnel and needs no shutdown time