# Presentation: 034883

## AGS Upgrade and Super Neutrino Beam

- DOE Annual HEP Program Review
- April 27-28, 2005
- Derek I. Lowenstein

## R&D Plan

- Long baseline neutrino experiments are a compelling  next high energy physics initiative in the US.
- BNL (AGS) and Fermilab (MI) are the two possible sources of neutrinos that could satisfy the neutrino intensity and energy spectrum.
- The R&D effort focuses on a phase 1 delivery of 9 x 1013 protons / 0.4 sec (1.0 MW); 2.3 x 1021 protons/107 sec
- The AGS has previously delivered 7 x 1013 protons/ 2 sec (.14 MW); 3.5 x 1020 protons / 107 sec
- Ultimate possibility of 1.8 x 1014 protons /0 .2 sec (4 MW); 9 x 1021 protons / 107 sec.

## AGS Intensity History

- 1 MW AGS

## High Beam Power Proton Machines

## AGS Alternative Intensity Enhancement Paths

- Linac upgrade
- Conceptual design in 2004 neutrino experiment proposal
- FFAG
- An old concept with a new twist
- Under investigation

## Path to increased intensity

- Minimize space charge at injection to the Booster and the AGS
- Maximize AGS repetition rate

## Slide 7

## AGS Proton Driver Parameters

- 	present AGS	**1 MW AGS**	**4 MW AGS**	J-PARC
- Total beam power [MW]	0.14	1.00 	4.00	0.75
- Beam energy [GeV]	24	28	28	50
- Average current [A]	6	36 	144	15
- Cycle time [s]	2	0.4	0.2	3.4
- No. of protons per fill	0.7  1014	0.9  1014	1.8  1014 	3.3  1014
- Average circulating current [A]	4.2	5.0	10	12
- No. of bunches at extraction	6	24	24	8
- No. of protons per bunch	1  1013	0.4  1013 	0.8  1013 	4  1013
- No. of protons per 107 sec.	3.5  1020	23  1020	90  1020	10  1020

## AGS Upgrade to 1 MW 

-   1.2 GeV superconducting linac extension for direct injection of  ~ 1  1014 protons	low beam loss at injection; high repetition rate possible	further upgrade to 1.5 GeV and 2  1014 protons per pulse possible (x 2)
-   2.5 Hz AGS repetition rate	triple existing main magnet power supply and magnet current feeds	double rf power and accelerating gradient	further upgrade to 5 Hz possible (x 2)

## Several of the items that were discussed in the October 2004 CDR will require R&D support.

**A second approach has developed since the CDR.**
**Not everything has to be reinvented by a particular laboratory, so we will take full advantage of Fermilab’s NuMi experience and future R&D efforts, BNL’s and JLab’s experience with the SNS.**

## 1.2 GeV Superconducting Linac

- Beam energy 	0.2  0.4 GeV	0.4  0.8 GeV	0.8  1.2 GeV
- Rf frequency	805 MHz	1610 MHz	1610 MHz
- Accelerating gradient	10.8 MeV/m	23.5 MeV/m	23.4 MeV/m
- Length	37.8 m	41.4 m	38.3 m
- Beam power, linac exit	17 kW	34 kW	50 kW

## Some other areas that require further study

## Beam Loss at H- Injection Energy

- 	AGS 	PSR 	SNS	**1 MW AGS**	Booster	LANL
- Beam power, Linac exit, kW	3	80	1000	50
- Kinetic Energy, MeV	200	800	1000	1200
- Number of Protons NP, 1012	15	31	100	100
- Vertical Acceptance A,  m	89	140	480	55
- 23	0.57	4.50	6.75	9.56
- NP /23 A), 1012 m	0.296	0.049	0.031	0.190
- Total Beam Losses, %	5	0.3	0.1	3
- Total Loss Power, W	150	240	10001440
- Circumference, m	202	90	248	807
- Loss Power per Meter, W/m	0.8	2.7	4.0	1.8

## AGS Injection Simulation

- RF voltage	450kV
**Injection parameters:**
- Injection turns	360
- Repetition rate	2.5 Hz
- Pulse length	1.08 ms
- Chopping rate	0.65
- Linac average/peak current	20 / 30 mA
- Momentum spread	 0.15 %
- Inj. beam emittance (95 %)	m
- Bunch length	85 ns
- Longitudinal emittance	1.2 eVs
- Momentum spread	 0.48 %
- Circ. beam emittance (95 %) 100m

## New AGS Main Magnet Power Supply

- 	_**Upgrade**_	_**Present**_
- Repetition rate	2.5 Hz	1 Hz
- Peak power	110 MW  	50 MW
- Average power	4 MW  	4 MW
- Peak current	5 kA        	5 kA
- Peak total voltage	 25 kV 	  10 kV
- Number of power converters / feeds	6	2

## Eddy Current Losses in AGS Magnets

- For 2.5 (5.0) Hz:
- In pipe: 	65 (260) W/m
- In coil: 	225 (900) W/m

## AGS RF System Upgrade

- Use present cavities with upgraded power supplies (two 300 kW tetrodes/cavity)
- 		_**Upgrade**_	_**Present**_
- Rf voltage/turn	0.8 MV	0.4 MV
- harmonic number	24	6 - 12
- Rf frequency	~ 9 MHz	3 - 4.5 MHz
- Rf peak power	2 MW
- Rf magnetic field	18 mT

## Beam line to your favorite western mine

**Beam line to your favorite western mine**

## Neutrino Beam Production

- 1 MW He gas-cooled Carbon-carbon target
- New horn design
- Target on down-hill slope forlong baseline experiment
- Beam dump well above ground water table to avoid water activation

## Costs

- The October 2004 proposal has an initial estimated direct construction cost of _$273M_.
- TEC of $407M (FY04$), including a 30% contingency and 14.5% overhead.
- The incremental AGS operations costs to HEP, concurrent with RHIC, is estimated to be the order of $25M (FY05$) for a 35 week per year operation.
- Cost is dependent upon sharing beam time with other programs using the AGS at the time.

## Slide 21

## Path Towards >1 MW

- 	**Upgrade I**	**Upgrade II**	**Upgrade III**
- Linac intensity/pulse	1.0  1014 	2.0  1014 	2.0  1014
- Linac rep. rate	2.5 Hz	2.5 Hz	5.0 Hz
- Linac extraction energy	1.2 GeV	1.5 GeV	1.5 GeV
- 23	9.6	14.9	14.9
- Beam power	54 kW	144 kW	288 kW
- AGS intensity/pulse	0.9  1014 	1.8  1014 	1.8  1014
- AGS rep. rate	2.5 Hz	2.5 Hz	5.0 Hz
- Rf peak power	2 MW	4 MW	8 MW
- Rf gap volts/turn	0.8 MV	0.8 MV	1.5 MV
- AGS extraction energy 	28 GeV	28 GeV	28 GeV
- Beam power	**1 MW**	**2 MW**	**4 MW**

## 4 MW AGS Proton Driver Layout

**4 MW AGS Proton Driver Layout**

**200 MeV Drift Tube Linac**

**BOOSTER**

**High Intensity Source**
**plus RFQ**

**Superconducting Linacs**

**To RHIC**

**400 MeV**

**800 MeV**

**1.5 GeV**

**To Target Station**

**AGS**
**1.2 GeV ******** 28 GeV**
**0.2 s cycle time (5 Hz)**

**0.1 s**

**0.1 s**

**200 MeV**

## A new use of an old idea. 
An FFAG injector to the AGS.

- An FFAG injector to the AGS.

## FFAG proton drivers

- Renewed interest in Fixed Field Alternate Gradient (FFAG) accelerators  [F. Meot (Saclay)]
- Advantages: High repetition rate (~ kHz), final energy > 1 GeV
- Successful demonstration of scaling (fixed tune) FFAG  [Y. Mori/S. Machida (KEK)]
- Non-scaling designs with small tune variation are being developed
- Example: Idea of a 10 MW proton driver: [A. G. Ruggiero (BNL)]
- 1 GeV,  10 mA , 10 MW, 1 kHz
- After FFAG: DF: ~ 3 x 10-4, Ipeak ~ 30 A
- Issues: High rf power, fast frequency tuning,             complicated magnetic field profile

## AGS Upgrade with 1.5-GeV FFAG

**	****	****   ****Performance**
- Rep. Rate	        0.4      ->    2.5 Hz
- Top Energy	         28 GeV
- Intensity 	        0.70    ->    1.0 x 1014 ppp
- Ave. Power       0.125  ->    **1.0 MW**

**1.5**-GeV FFAG

- AGS Cycle with 1.5-GeV FFAG

- 0.4 sec

- 1.2-GeV SCL

## R&D funding request

- We are preparing an accelerator R&D funding request (FY06) to  investigate cost saving and performance enhancing alternatives for the development of a next generation neutrino source, directed towards a long baseline experiment.
- Simulating the space charge effects of high intensity beams.
- Reducing the costs and improving the reliabilty of the proton source and the neutrino production target station.
- Study the FFAG as an alternative to a high energy linac.

## Conclusion

- An upgraded AGS with 1 MW
- (further upgradeable to 2 and 4 MW)
- beam power is a cost effective and
- competitive proton driver for a
- neutrino super-beam long baseline
- experiment.