# Presentation: 713690

## MCTF View of Scenarios

**MCTF View of Scenarios**

**Y.Alexahin**
**(FNAL)**

## Parameters of Different MC options

**Parameters of Different MC options**

- 			Low Emit.	High Emit.	MCTF06	MCTF07
- s  (TeV)					1.5
- Av. Luminosity (1034/cm2/s) *	2.7	1	1	1.33-2
- Av. Bending field (T)		10	6	8.33	6
- Mean radius (m)		361.4	500	363.8	500
- No. of IPs			4	2	2	2
- Proton Driver Rep Rate (Hz)	65	13	60	40-60
- Beam-beam parameter/IP	0.052	0.087	0.1	0.1
- * (cm)			0.5	1	3	1
- Bunch length (cm)		0.5	1	2	1
- No. bunches / beam		10	1	1	1
- No. muons/bunch (1011)	1	20	12	11.3
- Norm. Trans. Emit. (m)	2.1	25	13	12.3
- Energy spread (%)		1	0.1	0.1	0.2
- Norm. long. Emit. (m)		0.35	0.07	0.14	0.14
- Total RF voltage (GV) at 800MHz	407103c	0.21** 	0.26103c	0.84**
- Muon survival N/N0		0.31 	0.07	 floss 	0.2
- + in collision / proton		0.047 	0.01	0.15	0.03
- 8 GeV proton beam power	3.62*** 	3.2	0.6/ floss 	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
- ***) 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).
- )  floss  =  muon losses during cooling and acceleration, which has not yet been fully simulated

## MC options

**MC options**

**Low emittance option**
**it is more of a dream than an option so far: **
**- no convincing ideas of how to incorporate RF into HCC**
**- no proof that HPRF will work under ionizing beam**
**- no viable design for the next cooling stages – PIC/REMEX **
**- no collider lattice design with necessary parameters**
**High emittance option**
**a rather solid ground under the feet, but not without its risks and deficiencies:**
**- high muon bunch intensity 2********10****12**** **
**- slow cooling resulting in poor muon transmission**
**- enormous p-driver bunch intensity**
**MCTF scenario**
**tries to alleviate the shortcoming of the high emittance option by borrowing some ideas from the low emittance option:**
**- faster 6D cooling by using HCC and/or FOFO snake**
**- bunch merging at high energy (20-30GeV)**
**- additional cooling using Fernow lattice or PIC (may become possible due to later bunch merging and lower total intensity)**
**- increased reprate to compensate for reduction in peak luminosity**

## Cooling Schemes in HE and MCTF Scenarios

**Cooling Schemes in HE and MCTF Scenarios**

- bunch coalescing

- 201 MHz FOFO snake

- new Fernow or PIC

## R. Palmer’s suggestion

**R. Palmer’s suggestion**

**According to Bob, he abandoned the idea of the ****New Ring**** employing one of Rick’s lattices due to strong Space Charge effects. Will a 10-fold reduction in intensity help?**
**Starting with much lower transverse emittance, will it be possible to cool it down to ~10 ********m without excessive longitudinal blowup in 50T solenoids?**

## Where we are w.r.t. LE option?

**Where we are w.r.t. LE option?**

**MCTF**

**we are not so outrageous optimists after all!**

## 201 MHz FOFO snake

**201 MHz FOFO snake**

**Cell length =3.2 m, solenoid inner radius = 40cm, Bmax=2.4 T at p=100MeV/c**
**HPRF cavities  2×16cm long, E=25MV/m, GH2 fill with density 10% of LH2 **
**Emittance decrement 1/25m, equilibrium emittances ~1.5 ********mm**

## Emittances & Transmission in HE/MCTF schemes

**Emittances & Transmission in HE/MCTF schemes**

**stage****	****	****	**** ************N**** (********mm)****	**** ****	********||N  ****(********mm) ****	****transmission**
**High emittance option**
**RF capture/rotation****	****	****20****	****	****40****	****	****-**
**4D cooling in linear channel****	****12****	****	****40****	****	****0.7**
**201/402 MHz RFOFO****	****	****1.4****	****	****1.4****	****	****0.45**
**bunch merging****	****	****1.4****	****    21×1.4= 30****	****	****0.8**
**201/402 MHz RFOFO****	****	****1.4****	****	****5****	****	****?**
**804 MHz RFOFO****	****	****0.38****	****	****1.2****	****	****0.55**
**50T solenoids****	****	****0.025****	****	****65****	****	****0.7**
**Acceleration****	****	****0.025****	****	****65****	****	****0.7**
**	****	****	****	****	****	****total=****	****0.068**
**MCTF scenario**
**RF capture/rotation****	****	****20****	****	****40****	****	****-**
**201 MHz FOFO snake****	****	****3****	****	****5****	****	****0.85*******
**402/804 MHz HCC****	****	****0.7****	****	****0.5****	****	****0.9*******
**Fernow channel (PIC?)****	****0.07****	****	****0.5****	****	****0.5(?)**
**50T solenoids****	****	****0.012****	****	****14****	****	****0.85**
**Acceleration (total)****	****	****0.012****	****	****-****	****	****0.7**
**bunch merging****	****	****0.012****	****	****140****	****	****0.85**
**	****	****	****	****	****	****total=****	****0.19**
**----------------------------------------**
***) Critically depends on success with HPRF**

**N protons/bunch ~ 10****12****/ 0.15/ 0.19 = 3.5 ×10****13**** at 8GeV**

## REMEX in 50T Solenoids (R.Palmer)

**REMEX in 50T Solenoids (R.Palmer)**

- *LN* (mm)

- no momentum tail cut

**MCTF path does not seem to contradict Bob’s simulations, in fact it is based on them!**

## Critical Issues for MCTF Scenario

**Critical Issues for MCTF Scenario**

****** ****proof that HPRF will work under ionizing beam**
**       ****- Alvin is doing theoretical analysis, experiments at MuCool TA under preparation**
****** ****incorporation of RF into HCC**
**       ****- Katsuya and others are working hard to find a viable solution**
****** ****technological**** ****feasibility of 50T solenoid **
****** ****complete design of 50T solenoid channel with matching and RF**
**       ****- BNL team**
****** ****p-driver scheme capable of delivering 4×10****13**** protons on the target in a 3-5ns pulse**
**       ****- Chuck Ankenbrandt and Dave Neuffer are working on schemes based on the              Project X linac**
**       ****- collaboration with the Heavy Ion Fusion Science Virtual National Laboratory (Will Barletta is one of the leaders) to study the feasibility of high gradient induction linac?**
** **

## FY08 MCTF Design & Simulations Plan

**FY08 MCTF Design & Simulations Plan**

**Collider ring:**
**	******** ****Optimization of the collider ring design**
**	******** ****Study of implications of the “dipole first” option for detector protection**
**	******** ****Beam-beam simulations**
**	******** ****Detailing of the design with corrector circuits, injection and collimation systems**
**Basic 6D ionization cooling:**
****** ****“****Guggenheim” RFOFO channel:**
**	******** ****More realistic modeling of the magnetic field **
**	******** ****Alternative design with open cell RF cavities with solenoids in the irises**
****** ****Helical cooling channel**
**	******** ****Design of RF structure which can fit inside the “slinky” helical solenoid**
**	******** ****Design and simulation of the segmented channel**
****** ****FOFO snake:**
**	******** ****tracking simulations and optimization**
****** ****Side-by-side comparison of the three structures with the aim of choosing the baseline scheme**
**Final cooling:**
****** ****Complete design of the 50T solenoid channel with required matching between the solenoids**
****** ****Channel design incorporating Fernow’s lattice with zero magnetic field in RF**
****** ****Feasibility study of the PIC/REMEX scheme**

## FY08 MCTF Design & Simulations Plan (continued)

**FY08 MCTF Design & Simulations Plan (continued)**

**Driver:**
****** ****Schemes based on the Project X linac**
**	******** ****high reprate at 8GeV**
**	******** ****with acceleration in MI to 30-60GeV**
****** ****High-gradient induction linac**
**Muon acceleration**
****** ****RLA**
****** ****Fast ramping synchrotron**
****** ****FFAG for the initial stage**
**Bunch coalescing**
****** ****More realistic modeling of the bunch merging process at initial stages of 6D cooling**
****** ****Alternative scheme with bunch coalescing at high energy (~30GeV).**