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

The DORIS storage ring with photon-beamlines

Comparison of Blast with Argus

View to the IP-region from outside with ARGUS on the left side

Sketch of the situation at the IP

View to the IP – the cavities has to be moved to SL 26m

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