august 11, 2011 fnal meeting global design effort 1 dr-cfs discussion mark palmer gde

Global Design Effort 1August 11, 2011 FNAL Meeting

DR-CFS Discussion

Mark PalmerGDE

Global Design Effort 2

DR Layout (BTR version)

August 11, 2011 FNAL Meeting


Topics for Today• Magnet System Heat Load Update• Review of Tunnel Elements

– Alcoves & Caverns– Cross Sections

• Miscellaneous• Discussion and other

• Afternoon Discussion– Central Region Layout



Heat Load Estimate• Get away from % estimates of heat transferred to

air vs water (depends on relative temperatures and affected surface areas).

• So attempt a better estimate as follows:1. Convective heat transfer to air (non-forced):

~25W/m2/°C (high-end coeff. for non-forced case)where we need to consider the differential in temperature between the air and the avg magnet temperature

2. For non-cooled cables, treat full heat load as transferred to air

• Discuss on next 2 pages…



Magnet Heat Loads• Convective piece (ie, what fraction of magnet

heat goes to air…)– Estimate 0.5m2 of effective magnet surface area

per ring per meter of length– Thus we can write:

– So we have a ~25W/m convective contribution per ring for setting the air temp set point 2°C away from nominal water-based average temperature.

– But don’t forget to include fixed piece…August 11, 2011 FNAL Meeting


Contribution from Cables• Rough estimate is that cable losses will likely

be 5-10W/m per ring

• Note: all estimates based on arcs (region with highest conventional magnet load)

• Note: still need to do a full conceptual design update for the power supply system due to the significant changes in magnet strengths



Overall Contribution• Key assumptions:

– Fixed water supply temperature everywhere in ring a this implies that the operating point in different regions of the ring will be slightly different

– Convective estimate– Re-calculated cable loads based on new cable

runs for the DTC lattice• This suggests that we can hold the total heat

load per ring to the 30-50 W/m level as long as we have the control structure necessary to set the air temp in each section



Comments?• Would welcome any comments you might

have on carrying out the updated analysis in this way…



Alcoves and Caverns



Alcove Locations• RF cavern a OK• 4 AORs a OK• Alcoves to ELTR/PLTR a OK

– Septa PSs can potentially go here– May need some straight ahead radiation protection from

ELTR/PLTR lines • Inj/Ext Straight PS alcoves need to be next to kickers

between the ELTR and PLTR sections• May need a bump-out at the end of the wiggler

straight for a straight-ahead photon stop exiting through the first dipole.

• Need to discuss options for beam size monitor lines at some point



Cross Sections• Cornell designer (Joe Conway

<[email protected]>) picking up Norbert’s designs

• Will allow considerably better cross-checking (and will look at a further reduction in beam line separation) with the new designs

• DTC01 – 2 arc cells



Some Cross-Sections



Miscellaneous Issues• Ozone – primarily a wiggler region concern

– Thermal jackets around VC – is there boil-off N2 available to have a slow flow to prevent ozone build-up?

• Shaft size – Can we lower magnets already aligned on beams?



Central Region Definitions• Region A

– Injection to and extraction from the DR• e+ injection side

– e+ injection septum 78.66m from centerline of DR» Angle1 = 105.6 mrad @ Dx=0m» Angle2 = 243.0 mrad (total) @ Dx=21.3m» End of line @ Dx=27.16m (Dy=3.735m)

– e- extraction septum 77.64m from centerline of DR» Angle1 = 106.6 mrad @Dx=0m» Angle2 = 215.16 mrad (total) @Dx=23.3m» End of line @ Dx=27.41 (Dy=3.326m)


august 11, 2011 fnal meeting global design effort 1 dr-cfs discussion mark palmer gde

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