Discussion of min/max 4GLS energies 5th March 2007

Magnet designs going 550->600 MeV would be different
RF 550->600 MeV is increased gradient rather than power (check with Peter?)
Cryogenic load would be increased going 500->600 MeV
Collimation depth 550->600 would be increased
Water cooling 550->600 would be increased
CSR emitted power in HACL 550->600 MeV would increase.

Could consider and increase of energy with a decrease of current, to allow greater exploration of undulator output wavelength.

Twin-line variability:
We can straightforwardly change the HACL energy by turning off the XUVFEL.
In the present spreader design the energy ratio is fixed. So
550->600 MeV means 750 MeV->818 MeV on XUVFEL (for same energy ratio), so therefore XUVFEL injector goes 210->228 MV (assume same phases in everything) - the phase might be possible to change (but is complicated!)
The change 540->590 is 9%
The change 210->228 is 8%, so this can be done

So output energy of XUVFEL would now be 818 MeV.

Lower limit is around HACL 450 MeV - no real lower limit identified yet, except perhaps wakes (cavity/resistive and CSR) inducing larger energy spread on the bunch. The VUVFEL may stop working.

Upper limit on cavities is 20 MV/m, which is about 650 MeV. It is agreed to cost items (magnets, collimators, PSUs etc.) at 650 MeV (HACL). Need to work out what this is in XUVFEL line.

It was agreed that no inter-line energy variability is assumed - if operating together, the energy ratio is fixed at 550/750.

EMMA Design Review 27th February 2007

Day 2

RF Requirements - Scott Berg
RF Aperture 34.751 mm (diameter), assumes 0.439 mm offset
Flanges can be different sizes, maybe can help put up the shunt impedance
Also add 3mm for phase-space-painted energy spread/dispersion in ring

BPMs can resolve 16 pC vertically and 25 pC horizontally.
50 um resolution is what is required.

EMMA Design Review 26th February 2007

Neil Bliss - Specification Update

Can there be a window between ERLP and EMMA? Check this action - we know that the emittance is increased, but what about the energy spread and bunch length.


Run ERLP at lower gradient? Need to run some S2E simulations with lower gradient. Check after Bruno's presentation.
People have been talking about 19 cavities rather than 21.
Geometry of magnets has been changed to make F and D parallel in each cell now.
F magnet translation has reduced substantially to only a few mm.
RF cavity length has been increased 105 to 110 mm to increase the shunt impedance.
Field clamp plates have been added to the engineering drawing.
Injection by Carol may be on inside of the ring. This raises the possibility of having the ring anticlockwise rather than clockwise.
Single girder option is being considered - arc sections would be machined and then linked together.
When the quadrupoles move, their fields will push on each other and therefore move the magnets slightly on their slides. This effect needs to be examined.

Scott Berg - Lattice Update

The lattice elements in one cell are now all co-parallel; a very small increase in apertures
Frequency range in cavities has to be increased to allow scanning over energy range.
The end field in the magnets causes a horizontal position shift at large apertures, which affects the required aperture (it jumps at the end of the magnets, when plotted longitudinally).
Energy spread/length in input bunch may affect the energy spread, and therefore dispersion, and therefore aperture, in the ring. Need to check the longitudinal emittance and give to Scott.
The FODO option is basically discounted.
The RF cavities are offset from the cell centre-line, at least in the model, by about 0.5mm.

Modelling requirements;
Stefan Tzenov will look at modelling ERLP injector at 10 MeV, and estimate the injection parameters. Injection phase may be random (no sync lock between RF systems) and then measured, or instead synchronisation can be attempted.
Ideal emittance is about 12 mm-mrad. See if 10 mm-mrad is possible from the injector.
Check slice energy spread, projected energy spread, bunch length, peak current and longitudinal emittance from ERLP at this energy.

4GLS Planning Meeting, 23rd February 2007

Review of configuration v1.2

Things to check:
HACL Injector Energy Spread (uncorrelated)
XUV Injector outline parameters
Review of quadrupole strengths and lengths
Boris to check the geometry and layout of the HACL injector and associated equipment with the engineers
Check that 4m is available at end of XUVFEL Linac 3 for possible laser heater

Borehole investigation is about to start, on Monday 26th February
Artesian groundwater cooling to be investigated
Photon energy ranges required from IR-FEL are still unclear. For the purposes of the next year of design
VUV-FEL 3-10eV
XUV-FEL 8-100 eV
IR-FEL 2.5-25 um, 20 to 200um in two branches - separate operation only! A conceptual overview of alternatives (e.g. the simultaneous Klug scheme) is also to be included.

Chat with John Dainton

Just had a chat with John, and showed him all the great things you can do with Blogger.

AP Group Meeting 22nd Feb 2007

ASTeC Risk Register - to be reviewed.
EuroFEL booking and projections to be reviewed.
ASTAB Meeting - presentations went well.
4GLS funding - core project unlikely to be funded before 2010.
Group objectives - 4GLS and EuroFEL, HLO to do.
Bids for next FY - consider AP work.

CI Symposium - 15th February 2007

Mike Poole - ASTeC and the history of Daresbury Laboratory

1957 - Wilkinson proposes HE e synchrotron
1960 - Cockcroft + Cassels propose 4 GeV version
1961 - Cockcroft proposes Cheshire site
1962 - NINA approved
Proposed sites: Macclesfield, Crewe, Winsford, Risley, Skelmersdale
1963 - Daresbury selected

Mike Poole has some great photos of the history of the lab.

CICT/CI/ASTeC Support Meeting, 12th Feb 2007

Notes and actions:

I.Bailey - to do website updates on new CI web server during interim period.

J.Dainton - to discuss with M.Poole who will be website manager and to arrange that person to take over management of the website.

G.McBain - to look at option of filtering all CI outgoing mail at mailserver to appear to come from @cockcroft.ac.uk.

H.Owen/J.Smith - to circulate how to change 'Reply-to' addresses in Exchange/Outlook

H.Owen - to check with FBU IT whether all functionality is possible in Sharepoint web access using Firefox.

Decision - Arrange with B.Runcie and S.Eyres to do design and update of CI website.

J.Dainton - to provide budget code for website work.

C.Dean/J.Smith/H.Owen - to put printer Linux PPD files onto CI website.

G.McBain - to check IMAP/POP3 instructions for offsite email access for all types of users.

H.Owen - to email H.Gun-Why about site information for non-staff.

M.Enderby - to propose recommendations for CI data backup, e.g. server-based? on-site/off-site options, best practice instructions? strategy?

4GLS AP Meeting 8th Feb 2007

Martin's seminar on radiation protection - no change in our collimation/machine protection philosophy at the moment.
David Holder will book a meeting to brainstorm ideas about beam loss philosophy.
Spreader design - need to review once energy choice is made.

4GLS Layout Meeting 7th Feb 2007

Actions:
Boris Militsyn to provide draft HACL injector layout to engineers, including indications of power supply heights.
Simon Appleton to provide detailed layouts of v1.2 including internal cavity dimensions
Julian McKenzie to check that he has the correct x-section of HACL injector model.
Neil Thompson to check he has provided XUV-FEL ID layout information (quads); also minimum height for ID modules.