1. DR Interface to Sources and RTML
Mark Palmer
GDE
August 10, FNAL Meeting
Global Design Effort

2. DR Layout (BTR version)
August 10, FNAL Meeting
Global Design Effort

3. ELTR Block Diagram (Ewan’s Section A)
Electron Injection (reverse for e- extraction)
H-bend and horizontal dispersion suppressor section (10s of meters)
RDR treaty point
Transport line
Positron Extraction (reverse for e+ injection)
H dispersion suppresion (10s of meters)
RDR treaty point
Vertical elevator (V-bend a full-wave section a opposite V-bend, 10s, possibly man 10s, of meters)
Merging section (length depends on single element kick)
Vertical dispersion suppressor section (10s of meters)
Reverse arrows for PLTR region V E+
Pulsed & DC Separators E- E+ E-
H bend
x 2? V E+
August 10, FNAL Meeting
Global Design Effort

4. DR Injection-Extraction Lines
RDR picture
Concept based on lines created by I. Reichel for RDR, which include
Extraction
Dispersion control section
Extraction angle plus 1 bend result in transition into tunnel ~30m from septum location
Injection
Same basic concept in reverse
DO NOT handle any vertical adjustments!
August 10, FNAL Meeting
Global Design Effort

5. Reorganization for Post-RDR Straight
DR elements reorganized to put all Inj/Ext in one straight with the Central Region re-design
No direct impact on these lines
Beams should exit tunnel approximately 30 m from the septa
Consistent with present ELTR/PLTR layout at few meter level (item to fine tune for January)
RDR picture
August 10, FNAL Meeting
Global Design Effort

6. DR Layout (BTR version)
Beam lines at ~3.75 m from axis of DR straight with final angle of 243 mrad (13.9°). Location ~30 m “outboard” of inj/ext septa
August 10, FNAL Meeting
Global Design Effort

7. Implications Initial horizontal dispersion correction complete
Should keep this to avoid coupling into vertical emittance due to errors
Thus vertical “elevator” is effectively in the central region tunnels, NOT part the ELTR/PLTR
August 10, FNAL Meeting
Global Design Effort

8. Vertical Elevator Section
Comments
10mrad a ~100m length (1mrad a ~1km!)
Hesitate to go with larger kick due to the magnitude of the vertical dispersion created with reasonable strength quads
To what precision can we null this vertical dispersion?
Pulsed elements for merger (or splitter)
10mrad scale should be fine for slow pulsed elements (ie, inject/extract positron rings one after the other).
Fill pattern discussions have led to the tentative conclusion that we likely need to support alternating bunch extraction from the rings to flexibly meet any of the possible ML bunch spacing requirements!!
Alternating bunches from the two rings will require a ~3MHz AC element (or elements). What kick magnitude can we assume per unit? What technology.
Stability specification directly impacts level at which vertical dispersion is nulled.
August 10, FNAL Meeting
Global Design Effort

9. Vertical Elevator Section (cont’d)
Comments (cont’d)
Dispersion suppression elements
Will this need a pulsed dispersion correction of some sort???
Do we need to measure/monitor the vertical emittance at the end to adequately correct?
Allowing a dispersion wave to propagate sounds like a VERY bad idea to me.
August 10, FNAL Meeting
Global Design Effort

10. Needs Lattice designer to lay out the vertical “escalator”
Explore expected level of dispersion correction versus escalator length with realistic errors. Pass these numbers to the Low Emittance Transport group to evaluate impact of residual dispersion wave.
Who??? Needed immediately
Could we target a report for a joint session at Granada?
Immediate review of pulsed element options for splitter and merger operation
Contact multiple pulsed magnet experts
Request attendance at Granada for joint session? At least will need a report
Target an escalator configuration down-select at Granada? Then document for DESY meeting.
August 10, FNAL Meeting
Global Design Effort