# Presentation: 684217

## Some Proposals for ILC Beam Test Facilities at FNAL

- Mike Church
- ILC R&D Meeting
- 4/19/06

## Where Did This Come From? -- Agenda and Attendees for Initial Discussions on Beam Facilities – 3/14/06

## 5 Tiered Proposals

## Beam Test Facilities and What Can Be Learned from Them

## Flat Beams from Photoinjector

|   | A0 photoinjector | A0 photoinjector - comment | ILC |
| --- | --- | --- | --- |
| bunch charge (nC) | up to 16 |   | 3.2 |
| bunch spacing (nsec) | 1000 |   | 330 |
| RF pulse length (ms) | up to .6 | new gun design required to prevent overheating and breakdown | 1 |
| pulse repetition rate (Hz) | 1 | requires RF upgrade to increase rep. rate | 5 |
| normalized horizontal emittance (mm-mrad) | 40  (@ 0.5nC) |   | 8 (DR extraction); 10 (IP) |
| normalized vertical emittance (mm-mrad) | .4  (@ 0.5 nC) |   | .02 (DR extraction);  .04 (IP) |
| emittance ratio | 100  (@ 0.5nC) |   | 400 (DR extraction); 250 (IP) |
| RMS bunch length after bunch compression (mm) | .5  (@1 nC) |   | .3 |
| RMS momentum spread  after compression (%) | ~4  (@1 nC) |   | 1.1 |
| polarized? | no | R&D in progress -- vacuum issues may be difficult | yes |

## ILCTA @ New Muon Lab

**P. Piot**

**round to flat beam transformation**

**(will be 3)**

## Emittance Evolution in the ILC Main Linac

- Lattice is “BCD” with 1 Quadrupole per 4 Cryo Modules. Length of a FODO cell is 86 m. Number of cells is 114
- Initial Beam Energy is 15 GeV, final 250 GeV
- Initial Vertical Normalized Emittance is 20 nm*rad
- The plot shows that large emittance growth occurs in the first 10 FODO cells (~1 km length), even with all steering algorithms applied (both 1-1 steering and Dispersion Free steering applied).

**A. Valishev**

**Projected vertical emittance, using MATLIAR**

## Emittance Evolution in a Model Test Facility Linac

- Simple model of a Test Linac: 10 FODO cells of ILC (~1 km)
- Initial Beam Energy is 100 MeV, final energy 23 GeV
- Initial Vertical Normalized Emittance is 20 nm*rad
- With nominal element misalignments and no steering applied the emittance growth of 2 orders of magnitude is observed

**A. Valishev**

**Projected vertical emittance, using MATLIAR**

## Civil Construction Issues (5 GeV linac)

**A 5 GeV linac should duplicate as much of the ILC infrastructure as possible:**
** ****2 tunnel design**
** ****identical RF and cryo distribution systems**
** ****1 cryoplant/service building**
** ****large access shaft plus emergency egress paths**
** ****vertical curvature**

## Possible Location of 500m Linac Inside Tevatron Ring

**500m linac**

**C0 collision hall**

**approximate site of PD**

## A Survey of e- Rings

| e- Ring | Energy (GeV) | Circ. (m) | Bunch Int. (E10) | #  Bunches | Beam Current (A) |
| --- | --- | --- | --- | --- | --- |
| ILC | 5.0 | 6000 | 2 | 2820 | 0.451 |
| CESR-C | 5 | 768 | 1.2 | 40 | 0.03 |
| KEKB (HER) | 8 | 3016 | 6 | 1388 | 1.35 |
| PEP-II (HER) | 9 | 2200 | 4.6 | 1230 | 1.23 |
| HERA | 30 | 6336 | 3 | 189 | 0.043 |
| VEPP-4M | 6.0 | 366 | 15 | 2 | 0.04 |
| BEPC | 2.2 | 240 | 20 | 1 | 0.04 |
| ATF | 1.3 | 138 | 1 | 20 | 0.07 |
| ALS | 1.9 | 197 | .5 | 320 | 0.390 |
| APS | 7 | 1104 | .7 | 324 | 0.099 |

**2 new DR proposals in progress:**
**-  HERA – competing with XFEL**
**-  CESRTF – conversion starting in 2008; 1.5 – 5.5 GeV; e****+**** and e****-****; low emittance (3nm); up to .36A(??); competing with CHESS**

## Cross Section of HERA Magnet in Tevatron Tunnel

## HERA Tunnel and Magnets

## Possible Scheme for Positron Production and Acceleration

**Conventional positron target**
**Return beamline to front end of linac**
**Two options for acceleration**
**Accelerate positron bunches between electron bunches spaced at 308 nsec**
**Use widely spaced bunches so that interleaved positrons/electrons is not an issue**
**The point is to fill the positron ring for beam stability/emittance studies**
**Two options for DR configuration**
**Reverse polarity of magnets and circulate positrons in same direction as electrons**
**Keep polarity the same and have duplicate feedback, collimators, masks, aborts, etc**

## This is a Work in Progress with Many Questions Unanswered

**Could any of these facilities be (or evolve to) “the final thing”?**
**Should any of these facilities by deep underground?  Differences in ground motion, temperature/humidity control, etc?**
**Can (an upgraded) photoinjector satisfy emittance, intensity, and pulse train length requirements for linac and DR tests?**
**cost?  timeline?**
**Can competing facilities do better?  (CESRTF and HERA DR)**
**Can any of these facilities have “dual use”  -- ie, besides ILC beam physics/technology?**
** .........**