1. Central Region Working Group
K. Yokoya
CRWG meeting
ADI, , Yokoya

2. Charge (1)
To develop a conceptual design for the central region of the ILC
at a level of detail consistent with a change request and
sufficient to define the CFS features of this area of the machine.
The central region = downstream of the two main linacs:
e- source,
Undulator driven e+ source,
DR transfer lines (but not DR),
RTML,
BDS including associated hardware (dumps, collimators, spoilers etc..) IR
ADI, , Yokoya

3. Charge (2) Should assume Positron source
Detector Hall layout as specified in CR-003.
Tunnel geometry as specified in CR-004 (2x1.5km extension) and lattice ILC2015b.
ML tunnel cross-section as outlined for a 1.5 m central shielding wall (CR note the number changed 1312).
Positron source
Should be based on the undulator driven, positron source as modified by CR-011.
To be understood as the relocation of the 5GeV booster upstream
Should not incorporate any active features of a conventional positron source (e.g. klystron galleries, additional shielding, etc..) at this time.
Should however satisfy yourselves that the CFS layout you propose is consistent with the possibility of the subsequent adoption of such a source
should that prove advantageous at some point in the future.
ADI, , Yokoya

4. Charge (3)
Some of the information you will likely need is not completely specified at this time. Hopefully it will be available soon.
The Working Group will thus need to exercise a degree of judgment in how it approaches this task.
Avoid the temptation of trying to produce an engineering level of detail.
We are not scoped for such a task at this time
It is important to develop the central region concept in a timely way since changes have been made since the TDR and we need to progress towards a Kitakami site specific CFS footprint.
The Working Group should attempt to derive a cost- neutral (or cost reducing) approach
though I appreciate that the TDR baseline was estimated in a somewhat generic fashion for this part of the machine thus cost comparisons might prove difficult.
ADI, , Yokoya

5. Charge (4)
You should plan towards having a working concept for the ECFA workshop in Santander, in June (May 30 – Jun 5).
ADI, , Yokoya

6. Members BDS: Glen White, Toshiyuki Okugi, Sources: Masao Kuriki, CFS: Masanobu Miyahara, Tomoyuki Sanuki, General: Benno List, Ewan Paterson, Kaoru Yokoya
Meetings
Normally Tuesday, standard time (6pm California, 3pm EU, 11pm Japan)
Right after CFS (1hr earlier) …… what to do in DST?
Same time as TB
First meeting on Dec.15
Every other week
Archives?
ADI, , Yokoya

7. What must be considered? (1)
Positron line
Relocation of booster linac  decided already
Positron spin rotator
2 parallel line for up and down polarization (strong request from physics and positron groups)
Superconducting or normal-conducting solenoid?
Lattice in the undulator region --> positron group
Lattice in the booster  positron group
Auxiliary positron source
ADI, , Yokoya

8. What must be considered? (2)
Positron line
Global timing chicane (where?)
Insert a chicane with orbit length > 46cm (+-23cm) in the transfer line of produced positron to the DR
3 possibilities
At 400MeV
At 5GeV in BDS tunnel  lattice 2015b will include this
At 5GeV after the bend to DR
Controllability
Range of online control
Fine feedback for IP??
400MeV
5GeV DR
ADI, , Yokoya

9. Okugi. LCWS2015
ADI, , Yokoya

10. What must be considered? (3)
BDS line
Muon wall
Related to the transverse size of BDS tunnel
Relation to the background
To be studied by BDS group
Beam diagnostics section  Okugi
Collimator area
Required shielding
Amount of radiation  BDS
Beam dump (emergency dump, tune-up dumps, main dumps)
Abort kicker  BDS
Flat-top length
Dump hall design
Who? By when?
Emergency signal
ADI, , Yokoya

11. Okugi. LCWS2015
ADI, , Yokoya

12. What must be considered? (4)
Tunnel shape/size
Shielding wall
Local shielding in e+ target region, collimator region  estimation by positron group
Laser hut
But don’t go into detail of CFS
ADI, , Yokoya

13. What must be considered? (5)
Must take into account
Installation path
Where are the access halls?  CFS, cryogenics
Commissioning scenario
Human access when positron beam is on?? Ewan
Safety issues
Possible accidents
Must work with close link to CFS, BDS, positron
Else??
ADI, , Yokoya

14. Central Region Redundancy
From Ewan’s slides at LCWS
TDR
Electron source
2 guns, 2 lasers
Buncher: spare klystron
5GeV booster : 21 cryomodules + 3 spare, spare klystron
Energy compressor: 2x5MW klystrons installed
Positron
Spare undulator?
Spare target, flux concentrator, capture section
Warm RF, booster linac, ECS ?
ALL OF THE ABOVE NEED TO BE, UPDATED, AGREED UPON TO BE CONSISTENT WITH CFS LAYOUTS AND LATTICE, AND ARE INDEPENDENT OF THE DISCUSSION OF A THINNER SHIELD WALL OR TUNNEL CROSS-SECTION .
AUXILLIARY OR ALTERNATIVE E+ SOURCE DESIGNS WILL HAVE A LARGE LOCAL (over 1 or 2 km) IMPACT ON THE LATTER.
ADI, , Yokoya

15. Next meeting 2016 Jan. 5 23:00 Japan, 15:00 Europe, 6:00 west coast
ADI, , Yokoya