doris iii modernisation - desy · doris is a synchrotron radiation source with a high emittance,...

DORIS III Modernisation

DESY MAC, Nov 8th 2005F.Brinker, MDO

DESY MAC Nov 8 th 2005 2F.Brinker, DESY

Overview

Current status of DORISModernization programOptions for sharing preaccelerators with PETRASummary


Where we are now:

Synchrotron radiation runs:

140 mA in 5 bunches or 80mA in 2 bunches15-25 hours lifetime9 wiggler / undulator beam lines30 dipole beam linesAbout 5000 hours user operation per yearOrbit stability typ. < 1% of beam size ☺


Reliability95 %93 %96.9 %availability45 h61.8 h41.6 hMTBF

5100 h4761 h4538 hRun time2005 e20042003

DORIS III

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1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

average current[mA] integr. Current [Ah]electronruns


no. of beam losses in 2005 (jan-oct)

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beamlineinterlock

PowerSupplies

MBFeedback

RF cooling electr.Powerglitch

software Vacuum technicalinterlock

wigglerdamage

Failure breakdown 2005


DORIS is a synchrotron radiation source with a high emittance, which can not be reduced without a complete redesign ( 30 degrees bending angle )

Naturally Hasylab sets its focus on experiments which need a high flux of high energy photons

The number of users is constant around 2000/y and the number of experiment proposals is still growing.


DORIS has its strength in the VUV to hard X-Range regime for high flux applications

Flux density compared to other HGF sources


New Harwi wiggler beamline:Geo-Forschungszentrum PotsdamHigh-pressure instrument25 GPa; temp. up to 2000 Ksample volume of 1 cm3BW5 beam line:

s.c. split pair magnet, 10 T max.(52 mm split, 51 mm bore radius)

2 examples of recent beam line upgrades:


Presumably in 2007 will be decided whether DORIS will continue as a SR-source to complement PETRA and the FEL facilities

What must / should we do to prepare DORIS for the next x years of operation?


Old plants or machinery should be replaced if:1. The failure probability is high ( or expected to grow )2. The maintenance effort is intolerable high3. The beam quality can be significantly increased4. The investment costs are more than compensated by

reducing the operating expenses ( in terms of money or manpower )

Modernization Plan

Since the new installation would happen short after the rebuild of PETRA, we would have the chance to get similar ( or identical ) systems wherever possible with great advantages concerning maintenance and spare parts


Reliability and maintenance

> 2008230 V distribution from transformer down to the tunnel

2008Replacement of MBFB tube amplifier by semiconductor amplifier

> 200810 kV switch board

> 2008HV room, rf-controlling, klystron protection for one 500 MHz system

> 2008HV power supplies for both 500 MHz Rf-systems

2005/0610 kV cables from transformers to power sup.

Part in 2005/06, rest in 2008/09

Main magnet power supplies Schedule (expected)Installation


Reliability and maintenance 2 (cooling)

Basic fabric is corrodedReplace cooling tower with hybrid cooler

Demand for lower temperature and better stability

Cooling of experimentsCooling switchboard

Cleaning needs ~2 weeks shutdown each summer

RF cooling system no backup from PETRA after 2008 Water demineralizationremarkInstallation

In addition to increase the reliability and simplify the maintenance, we would profit from a significant step towards higher temperature stability


Reduce/ simplify maintenance

Spare parts no longer availablePart of analog electronicsInterlock systemLow temperature compressors

Make identical to PETRA and pre accelerator system

Control system software

Cavity and absorber cooling

Gone through all modifications of DORIS over 30 years!

Replace cooling installation in the DORIS tunnel

remarkInstallation


Beam quality

local tune compensation of wigglers

faster recovery after ventingreplace o-ring valves by all metal valves

increase TSP pumping capacitydone with new cooling systemincrease temperature stability

first IDs in DORIS with high field integrals, significant effect on orbit and dynamic aperture

replace wigglers W2 and BW3

avoid hysteresis effects and time lag

replace backleg windings with stand alone correction coils

mechanical vibrations ( 6-8 Hz)faster orbit feedbackRemarkInstallation


What will be used further on

new installed – 10 μm resolution, 300 Hz

BPM electronicnew installedcorrection power suppliesstate of the artRF station SR, long. FB transmitter

necessary modification done over the last years

vacuum system, cavities

radiation damage only on PU parts prepare order for dipole coils

magnet coilsno severe corrosion visiblemagnet yokesRemarkInstallation


Rough Estimation of costs and time schedule:

The investment costs are about 10 M €To minimize the risk of repelling users, the work could be done in two shutdowns of about 5 months duration each instead of one long oneThe planning and preparation would be done in 2007 and 2008The modernization could then be done in two shutdowns in 2009 and 2010To manage this in parallel to PETRA III and the XFEL project, additional staff would be needed.


Top Up option

A further step towards improved beam quality would be to run DORIS in a Top Up injection mode.

The technical possibility for frequent injections is given already now. The linac and synchrotron will be pushed for high availability for PETRA III in 2008.

The crucial point, which has to be worked out, is to fulfill theradiation security issues.

If one adapts the “permanent magnet” solution from PETRA this could demand a modification of each beam line.


PETRA III will use Top-Up injection for optimal conditions. It‘s not practical, if not impossible, to switch the particle

polarity within seconds

DORIS and Petra have to run both with the same particles

The last time DORIS has seen electrons was in 1993. Since then large parts of the vacuum system have been replaced. To examine the current lifetime behaviour we decided to make a 12 day e- test run in August.

Choice of particle type


2 days of electron runs with 5 and 2 bunch fillings:

This Lifetime was not relatedto dust


Statistics of 12 days e- operation in August 2005

Loss rates at DORIS with electrons within 4 hour time slots

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04.Aug.200505.Aug.200506.Aug.200507.Aug.200508.Aug.200509.Aug.200510.Aug.200511.Aug.200512.Aug.200513.Aug.200514.Aug.200515.Aug.200516.Aug.2005

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mean Loss Rate @ 140mA rms Loss Rate


Implications with electrons

no conversion target – less radioactivitymore redundant linacaccelerator sectionsrather simple electron gun

→ higher availability of the Linac

frequent lifetime reductions in DORIS down to 0.5 hmean lifetime is about half of that with positronsthat implies that DORIS has to run in Top-Up mode tooit seems not possible to upgrade DORIS for Top-Up during the PETRA shutdown 2008Also at PETRA lifetime reductions have been observed


Implications with positrons

conversion target needed with maintenance problemsavailability of linac is reducedhigh current electron gun needed

good conditions at DORIS and PETRA II are provencurrent DORIS operation (without Top-Up) is compatible with PETRA Top-Up – ejection from DESY at 4.5 GeV within the ramp to 6 GeV has been done recently


Summary

The success of DORIS encourages us to plan for the next one or two decades of DORIS operationAs a basis for the pending decision we prepare a modernisation programConcerning the startup after the PETRA III shutdown we state that DORIS still needs positronsTop up mode will be investigated to further increase the beam quality and allow the operation with electrons at a later stage if necessary

doris iii modernisation - desy · doris is a synchrotron radiation source with a high emittance,...

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