# Presentation: 556007

## MCTF progress & status

**Andreas Jansson**

## Introduction

- The directors charge to the MCTF is to investigate the long term prospects of a Muon Collider
- The main focus is on Muon Collider specific issues complementary to the NFMCC program
- E.g. 6D cooling, Collider optics...
- During this year, a joint MCTF/NFMCC 5-year R&D plan was developed and submitted to DOE.

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

## First beam in MTA line

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Beam to first beam stop, visible **
**on multiwire 3m upstream**

**Johnstone (talk this meeting)**

## MTA Beamline

- Permission for first beam into hall contingent on
- Shielding assessment approval by DOE
- Replacing shielding in pit and hatch.
- Will be low rate (1/min) for first experiment

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Johnstone (talk this meeting)**

## HPRF tests (w/o beam)

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Yonehara et al (talk this meeting)**

## Dependence on surface material

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Yonehara et al (talk this meeting)**

**(Note that there is **
**disagreement **
**as to whether **
**melting point the **
**relevant parameter**
**here)**

## 4-coil HCC model magnet

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Main goal is to develop the mechanical concept which could be extrapolated to the long solenoids without changing the structure**
**Each coil is wound from Rutherford type superconducting cable on a stainless steel bobbin**
**Outer stainless steel collar rings provide the coil support and intercept the radial Lorentz forces**
**The short model consists of four superconducting coils with support structures and end flanges**
**By operating at high current, 14 kA, it is intended to reach the fields, forces, and stresses of the long HS to verify the design concept and fabrication technology**
** **

**Kashikin et al (w. Muons Inc)**

## 4-coil model magnet tests

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Kashikin et al**

***Short sample limit **
**estimate 16K**

## Future HCC models

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**NbTi 4-coil model 2 plans**
** ****The base line of magnetic and mechanical design is the same as for Model 1**
** ****The design should accommodate NbTi and Nb3Sn cable technology**
** ****Need to improve mechanical structure and insulation:**
**	****- Place G10 spacers between turns to compensate for ****	****cable keystone**
**	****- Use the same ground insulation as in Model 1**
**	****- Correct the leads outlet areas to avoid shorts and**
**	****   ****carefully secure the leads in space outside the ****	****solenoid**

**Nb****3****Sn 4-coil model 3 plans**
** ****Same base line magnetic and mechanical design as for Model 2**
** ****Use the Nb****3****Sn ~ 15mm x 28 strands 1 mm diameter cable**
** ****Insulation and reaction details need to be worked out**

**Kashikin et al**

## HTS

- Single and double layer HTS coils designed and tested
- Modular HTS test facility designed and being procured
- Test many coils inside 16T solenoid
- BSCO-2212 cable and wire work will be done within National Collaboration

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Barzi (talk this meeting)**

## Optimal HCC Frequency

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Balbekov**

**Particles loss vs relative wavelength**
**(simulation at  250 MeV/c,  30 MV/m,  **
**15 MeV/m,  L = 1 m).**
** **
** **

**Perturbation of longitudinal motion by betatron       oscillations decreases the channel acceptance**

**Equilibrium emittance proportional to L!**
** **
** **

## How to make space for RF

- Possible to increase available aperture by  adding correction coils to the helical solenoid.
- Correction scheme will depend on required aperture for a given helix wavelength, and may be very challenging (impossible?) for short helix/high frenqency.

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**200 MHz RF**

**Yonehara (talk this meeting)**

## Can we make cavities smaller

**Toroidal cavity**

**Ceramic loaded cavity**

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Popovic (talk this meeting)**

**Balbekov**

**(HCC can work with **
**lower average gradient **
**and lower gas pressure)**

**(Also an idea for helical travelling wave **
**structure from L. Thorndahl/Muons Inc)**

## FOFO Snake

- Moved from planar snakes to helical snakes with some encouraging results.
- Need further study.

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**py**

**x**

**y**

******p**

**px**

**Alexahin (talk this meeting)**

## Weak Focusing PIC ring

- Weak focussing ring have large momentum acceptance and less problems with aberrations.

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Balbekov**

## RLA RF power estimate

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**HE2008, 1.5 TeV**

| 
N | Muon  losses,% | RF power, MW | Total cryogenic losses, MW | Losses in HOM couplers, MW | Total power, MW | Number of
klystrons (10 MW) | Number of cavities | Average klystron power, kW |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 10 | 6.4 | 20 | 4.8 | 1.5 | 24.8 | 180 | 2920 | 59 |
| 20 | 9.3 | 16 | 3.8 | 2 | 19.8 | 122 | 1460 | 70 |
| 30 | 11.1 | 14 | 3.5 | 2.2 | 17.5 | 92 | 973 | 81 |

**LE2008, 1.5 TeV**

| N | Muon  losses,% | RF power, MW | Total cryogenic losses, MW | Losses in HOM couplers, MW | Total power, MW | Number of
klystrons (10 MW) | Number of cavities | Average klystron power |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 10 | 6.4 | 68 | 13.9 | 1.8 | 81.9 | 90 | 2920 | 402* |
| 20 | 9.3 | 48.6 | 8.7 | 2.5 | 57.3 | 61 | 1460 | 424* |
| 30 | 11.1 | 42 | 7.4 | 2.8 | 49.4 | 46 | 973 | 486* |

***Available 10 MW klystrons have an average power of 150 kW****.**

**Yakovlev/Solyak**

## Wakefields in SC cavities

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Short range longitudinal wake per unit length:**
**W****max**** ~ *****q*****/(*****λσ******)***** for a “long” bunch  (*****λσ******>a******2*****, *****a***** - aperture)****.**

**σ****=1 mm**

**σ****=2 mm**

**σ****=4 mm**

**σ****=8 mm**

**For N=2e12, f=1.3 GHz (ILC-like structure) and ****σ****=8 mm W****max****= 6.2 MV/m!**

**Yakovlev/Solyak**

## Bunch timing

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Acceleration gradient along linac, **
***Red -one direction, ***
***Blue-opposite direction***

**Preferred **
**by RF **

**Preferred **
**machine**
**design**

**Yakovlev/Solyak**

## Collider Ring Optics

- “Dipole first”: bending magnets are introduced to create dispersion in the IR (not at IP) and accommodate sextupoles close to the IR quadrupoles (local chromaticity correction)
- Oide-like optics: Non-interleaved sextupole correction scheme requiring “ad hoc” optics and using a large number of sextupoles to control higher order chromaticity.

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**Gianfelice/Alexahin (talk this meeting)**

## The MCTF Scenario

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

**	****	****	****Low Emit.****	****High Emit.****	****MCTF07****	****MCTF08****	**
******s  (TeV)****	****	****	****	****1.5****	**
**Av. Luminosity (10****34****/cm****2****/s) *****	****2.7****	****1****	****1.33-2****	**** ****	**
**Av. Bending field (T)****	****	****10****	****6****	****6****	**
**Mean radius (m)****	****	****361.4****	****500****	****500     ********	****495**
**No. of IPs****	****	****	****4****	****2****	****2****	**
**Proton Driver Rep Rate (Hz)****	****65****	****13****	****40-60****	**
**Beam-beam parameter/IP****	****0.052****	****0.087****	****0.1****	**
******* (cm)****	****	****	****0.5****	****1****	****1****	**
**Bunch length (cm)****	****	****0.5****	****1****	****1****	**
**No. bunches / beam****	****	****10****	****1****	****1****	**
**No. muons/bunch (10****11****)****	****1****	****20****	****11.3****	**
**Norm. Trans. Emit. (********m)****	****2.1****	****25****	****12.3****	**
**Energy spread (%)****	****	****1****	****0.1****	****0.2****	**
**Norm. long. Emit. (m)****	****	****0.35****	****0.07****	****0.14****	**
**Total RF voltage (GV) at 800MHz****	****407********10****3********c****	****0.21** ****	****0.84** ******** ****	****0.3****†**
**Muon survival N********/N********0****	****0.31 ****	****0.07****	****0.2****	****?**
******+ in collision / proton****	****0.047 ****	****0.01****	****0.03****	****?**
**8 GeV proton beam power****	****3.62*** ****	****3.2****	****1.9-2.8****	****?**
**---------------------------------------------------------------------------****	**

***) Luminosity calculated taking account of the hour-glass factor but ignoring the dynamic beta effect.**
****) Momentum compaction in the present ring design ********c****=1.5********10****-4****. Note that it would be better to assume f=1.3GHz to keep the RF voltage at a reasonable level (0.52GV for MCTF07 set)**
*****) Assumes ******** /p ratio of 0.15 after capture and precooling, and only decay losses afterwards. Positive and negative muons are assumed to be produced independently (from different protons).**
**†****) The latest ring design has ********c****=5.5********10****-5****. Voltage for HE option is now 75MV**

**Alexahin**

## The 5-year plan

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson

|  | Now | Year 1 | Year 2 | Year 3 | Year 4 | Year 5 |
| --- | --- | --- | --- | --- | --- | --- |
| BNL | 6.5 | 7 | 8 | 10 | 10 | 10 |
| FNAL | 20.8 | 23 | 28 | 30 | 33 | 33 |
| LBNL | 2.5 | 6 | 8 | 9 | 11 | 13 |
| Other | 7 | 13 | 35  | 32 | 32 | 32 |
| TOTAL | 35.6 | 49 | 79 | 81 | 86 | 88 |

**Organisation**

**Budget request**

**Manpower needs**

**Geer et al (talk this meeting)**

## Summary

- Progress in many areas, despite very difficult year in terms of budget.
- More details in talks during this meeting.
- Focused most of M&S budget on completing MTA beam line.
- Expect beam into hall in a couple of months
- Major undertaking to propose 5-year plan in order to increase funding in coming years.
- We are ready to ramp up effort.
- Hopefully, “change is coming” (perhaps in the form of a large stimulus package).

- 1/25/09

**NFMCC meeting, LBL**

- A. Jansson