# Presentation: 586439

## Neutrino Factory R&D in Europe

***Helmut D. Haseroth***
***CERN, Geneva, Switzerland***

*or the art to talk for half an hour about nothing...*

## Organisation of European R&D:

Previously the CERN Neutrino Factory Working Group was quite active together with other European labs.

- Previously the CERN Neutrino Factory Working Group was quite active together with other European labs.

***Then came (BIG surprise?) the LHC catastrophy...***

*Huge reduction in accelerator R&D*

*CLIC cut drastically (to around 4 MCHF)*

*SPL* down to around 200 k€

- Neutrino Activity down to a bit of travel money

- (That‘s why I am still here...)

## There are, however, a few positive points:

- We have some (positive) impact from directors of big European labs with the intention to contribute towards neutrino R&D in spite of CERN‘s reduction!

**FIRST SET OF BASIC GOALS**
- The long-term goal is to have a Conceptual Design Report for a European Neutrino Factory Complex by the time of LHC start-up, so that, by that date, this would be a valid option for the future of CERN.* *
**  **
- An earlier construction for the proton driver (SPL + accumulator & compressor rings) is conceivable and, of course, highly desirable. The SPL, targetry and horn R&D have therefore to be given the highest priority.

- We have a **European Muon Concertation and Oversight Group (EMCOG)**

## EMCOG members

- Rob Edgecock

- Pascal Debut

**EMCOG members**

##  Charged me to create European working group called: ENG (European Neutrino Group).
Plenary meetings during Muon Weeks 

*Plenary meetings during Muon Weeks*** **

**Chair: ****	****	****	****Helmut D. Haseroth**
**Scientific Secretary: ****	****Rob Edgecock**
**Sub-working groups with conveners:**
- 	Proton Driver:
- 		SPL: 			   **Pascal Debu, Roland Garoby**
- 		Proton Rings: 		   **Chris Prior**
- 	Targetry: 			   **Roger Bennett**
-  	Collection: 			   **Jean-Eric Campagne**
- 	Frontend: 			   **Rob Edgecck**
- 	Muon Acceleration + Decay Ring: **Francois Meot**

*One person still from CERN...*

## MUON Weeks

-    MUON Weeks: Organized by V. Palladino:
-    3/year at different locations in Europe at participating labs. Covers physics and machine aspects.

*Resources at all European labs (manpower and money) very limited => ask the EU for support!*
*No hope in the past for support from EU neither for high energy physics nor for accelerators, especially not for CERN.*

## ...but now  there is FP6 (framework program 6) of the European Union

- and ECFA is encouraged to ask for EU support.

*Another committee of lab directors*

**have decided to form a European Steering Group on Accelerator R&D (ESGARD)**** **

## Slide 8

## Slide 9

## Neutrino Factories are part of ESGARD activities

## From the minutes of the Restricted ECFA, November 29, 2002

**From the minutes of the **_**Restricted ECFA, November 29, 2002**_
**The chairman thanked R.Aleksan and ESGARD for the enormous amount of work they have already done as well as M.Spiro who has set the project going (Applause). RECFA fully supports the steps taken by ESGARD in building up the bids and will closely follow its work**

**Statement made in the Chairman's Summary of Conclusions of the **_**December 2002 SPC meeting**_** at CERN**
** **
**The SPC strongly supported the effort to co-ordinate the accelerator R&D at the European level through the promotion of the ESGARD initiative to get support of the European Union. **

**From the minutes of the **_**Restricted ECFA, March 31, 2003**_
**RECFA was impressed by the huge amount of work done by ESGARD and congratulated them for having so successfully built the proposal on accelerator R&D to the 6th EU Framework Programme. This proposal includes 6 Joint Research Projects and 3 Networks Activities, which are all considered with high priority by RECFA**

## Not a lot of money for these activities. Typically 1 to 1.5 M€ for 5 years!

***Not a lot of money for these activities. Typically 1 to 1.5 M******€ for 5 years!***

## Slide 13

## CERN Scheme

## SPL basics

- Study group since 1999   
- design of a Superconducting Proton Linac (H-, 2.2 GeV).
-     higher brightness beams into the PS for LHC
-     intense beams (4 MW) for neutrino and
- 					radioactive ion physics

- CERN 2000-012

## SPL design parameters

**For neutrino physics, it has **
**to be compressed with an**
**Accumulator and a**
**Compressor ring into**
**140 bunches, 3 ns long,**
**forming a burst of 3.3 ********s**

## A large inventory of LEP RF equipment is available 

**(SC cavities, cryostats, klystrons, waveguides, circulators, etc.)**
**which can drastically reduce the cost of construction**

- LEP cavity modules in storage

- Stored LEP klystrons

## SPL lay-out

## SPL cross section

## Accumulator and Compressor Rings (“PDAC”)

**2 synchrotron rings**
**in the ex-ISR tunnel**

## Roadmap (1): 3 MeV injector

- 1) 3 MeV pre-injector		2006 at CERN
*On-going collaboration with CEA (Saclay-F) and CNRS (Orsay-F) to build, test and install at CERN a 3 MeV pre-injector based on the “IPHI” RFQ (Injecteur de Protons de Haute Intensité*)

## Roadmap (2): Linac4

*Idea: **	**Take only the **room temperature** part of the SPL (120 MeV) **	**and install it in the PS **South Hall**, to inject H- into the **PS** **Booster*
*	**	**	*    > *twice the number of protons/pulse in the PSB  **(5 10**13**)*

- 120 MeV, 80m, 16 LEP klystrons

## Linac4 layout in South Hall

- to inflector & PSB

## HIPPI

- In the frame of the CARE Initiative (ESGARD), *Joint Research Activity* called HIPPI (High Intensity Pulsed proton Injector) (total 6 JRA’s)
- 8 European Laboratories join efforts for a common R&D on high intensity linacs with energy in the range 3-200 MeV (CEA, CERN, ISN-Grenoble, GSI, IAP-Frankfurt, FZ Juelich, RAL, INFN-Mi) to prepare the upgrade of the proton accelerator facilities at CERN, GSI, RAL
- 4 Work Packages: 1. Normal-conducting accelerating structures
- 			2. Superconducting accelerating structures
- 			3. Beam chopping
- 			4. Beam dynamics
- Total investment of some 15 M€ (including lab salaries), request to EU for a contribution of 4 M€** **over 5 years (2004-08)

***For CERN, this means 130 k€/yr (...)******.***

## R&D Topics - CCDTL

- CCDTL = Cell Coupled Drift Tube Linac,
- a simpler and cheaper alternative to DTL for energy > 40 MeV

- quadrupole

- coupling cell

- DTL-like accelerating cell
- (2 or 3 drift tubes)

- CCDTL prototype

## Roadmap (3): SPL ...

- New technology can provide better performance (=gradient!)
- More EU-wide interest on 700 MHz frequency, bulk Nb
- Consequences:
- Slowly relax the option on the LEP cavities
- Consider 700 MHz already for the 100-150 MeV at Linac4.
- Start market survey for 700 MHz klystrons
- R&D options must be valid for both frequencies

## Preliminary Layout of Neutrino Factory

## European Scenarios 

- SPL + accumulator and compressor rings
- 5 GeV, 50 Hz synchrotron-based system
- 15 GeV, 25 Hz synchrotron-based system
- 30 GeV, 8 Hz slow cycling synchrotron
- 8 GeV, 16.67 Hz rapid cycling synchrotron for ISIS/Fermilab, plus upgrades

## CERN PDAC: Bunch Compression

## RAL 5 GeV Proton Driver

## ISIS MW Upgrades and possible use as a NF test bed

- 800 MeV,160 kW, 50 Hz, spallation neutron source
- Current upgrade to 240 kW with new ion source, RFQ and dual harmonic RF accelerating system

## Stage 1: upgrade to 1MW neutrons

- Addition of a new synchrotron to increase beam energy to 3 GeV at 50 Hz
- Operated at 16.67 Hz, with every third ISIS pulse, could take beam to 8 GeV and be used as a test bed for 1 ns bunch compression

## Stage 2: Upgrade to 4-5 MW

- Design and build new linac and two new booster synchrotrons with radius 39 m, operating at 50 Hz to 1.6 GeV (h=3)
- Build a second 78 m racetrack
- Operate the two racetracks at 25Hz on alternate cycles
- 2MW beam power in each rings
- 4MW neutron source
- 2MW to neutron target
- 	+ 2MW to pion target
- 4MW to pion target

- 78m radius

- 39m radius

- 180 MeV Linac

## Target Studies

**Target Studies**

## The Liquid Metal (Mercury) Jet

- The jet is constantly being reformed for every pulse. The jet becomes “heated” by the beam and disperses to hit the walls
**No Problems with:**
-  Radiation Damage
-  Shock Damage
-  Power dissipation
**Possible Problems with:**
-  Jet formation
-  Interaction with the magnetic field
-  Interaction of the mercury with other equipment
**Tests to date indicate that the jet is viable**

## Hg-jet p-converter target with a pion focusing horn 

- Hg-jet p-converter target with a pion focusing horn

## Targetry

- Proposed rotating tantalum target ring

**Targetry**

- Many difficulties: 	enormous power density						 lifetime problems	pion capture

- Replace target between bunches:
- Liquid mercury jet or rotating solid target

- Stationary target:

- Densham

- Sievers

## Granular Target

## A Water Cooled Cu-Ni Rotating Band Target (BNL and FNAL, Bruce King)

**A Radiation Cooled Rotating Toroid, (RAL)**
**TOROID OPERATES AT  2000-2500 K**
**RADIATION COOLED **
**ROTATES IN A VACUUM**
**VACUUM CHAMBER WALLS WATER COOLED**
**NO WINDOWS**
**SHOCK? Pbar target OK. Tests using electron beam simulation indicate no problem.**

## Individual Targets Levitated

**Individual Targets Levitated**

**V**

**Reservoir for targets to collect and cool**

*V* = *Lf*
*R* not fixed

- No threading solenoid

## Advantages of Solid Target

- No windows
- Cooling in the walls
- Simple concept
**Disadvantages**
**Large rotating toroid or individual targets**
**Problems if toroid breaks**
**Thermal shock - toroid breaks**
**Very radioactive**

## Tests by RAL with electron beams show that tantalum foils can withstand at least 200000 pulses and have lasted for 1000000. 

##     Problems with:

- 1. Solenoid, 10-20 Tesla
-       US consider they have a long life (>1 year)
-      design
- 2. Horn
-     Problems with:
-       Heat dissipation, Radiation damage, Stress
-       Possible 6 week life
-       Studies will continue

## Double horn concept

## Horn prototype ready for tests

## Acoustic frequency meas.

- Horn eigenfrequencies from horn “sound”

- Hz

- dB

## What we planned to do

- First “inner” horn 1:1 prototype
- Power supply for Test One:      30 kA and 1 Hz, pulse 100 s long
- First mechanical measurements
- Test of numerical results for vibration
- Test of cooling system
- Test Two: 100 kA and 0.5 Hz, 100 s long
- test of this power supply during last weeks
- Last test: 300 kA and 50 Hz

- Unknown schedule

- Goal: Horn Life-Time 6 weeks (2*108 pulses)

## Slide 48

## Hg-jet system

- Power absorbed in Hg-jet	1 MW
- Operating pressure	100 Bar
- Flow rate		2 t/m
- Jet speed		30 m/s
- Jet diameter		10 mm
- Temperature- Inlet to target		30° C- Exit from target	100° C
- Total Hg inventory	10 t
- Pump power		50 kW

## If you do not like this... 

***Try funneling!***
***B. Autin, F. Meot, A. Verdier***

## What are the problems?

- Proton beam power:		4 MW
- Target to cope with high power(must be a high Z target because of the modest proton energy)
- Horn to be pulsed at:		50 Hz(Linac frequency)

***It would be much simpler if we had only 1 MW and e.g. 12.5 Hz***

## How does it work?

- The proton beam is switched to 4 targets in sequence.
- Each of the 4 pion lines contains an integrated system of target and magnetic horn.
- The funnel is made of large aperture magnets with quadrupolar and pulsed dipolar coils.

- No exotic and expensive technology.
- Lifetime in excess of one year.
- Evolutionary design.

- Why a funneling system?

## Funneling step by step

## Horn Parameters

| Radius of the waist [mm] | 40 |
| --- | --- |
| Voltage on the horn  [kV] | 4.2  |
| Skin depth [mm] | 1.25   |
| Pulse length [s] | 93 |
| Peak current [kA] | 300 |
| Repetition frequency [Hz] | 50 → 12.5 |
| rms current in the horn [kA] | 14.5 → 3.6 |
| Power dissipation by current [kW] | 39 → 9.7 |

## Target dynamics

- High repetition frequency f reduces instantaneous energy deposited W at given power P: W = P/f .
- Long pulse heats the spheres adiabatically:        no shock.
-                                                                                                   									Without funneling
- 			                                                 																									With funneling

## Polarities

- Scheme 1: AC quadrupoles	 	Scheme 2: DC quadrupoles
- Good transmission.			Reduced transmission (2/3).
- Complicated power supplies due 	Conventional power supplies.
- to high stored magnetic energy.

## Muon production

- Y = N/Nversus longitudinal emittance for two transverse admittances:
- t = 1 cm (no cooling)
- t = 4 cm (cooling)

## Introduction

- Frontend

## CERN Baseline Frontend

- Replaced with an all 88MHz frontend ****** eliminates 44MHz****	****	****	****	****	****	**** cavities**

- target and horn:
-      as before

- 15 m decay channel

- 7.2 m phase rotation

- cooling (6.4 m/cell)

- Same performance as 44/88MHz channel

## Frontends without Cooling

**Frontends without Cooling**

- Grahame Rees et al

- Pion-muon decay channel

- 88 MHz muon linac

## Frontends without Cooling

**Frontends without Cooling**

- Transmission comparable to 44/88MHz scheme

## AG Phase Rotation

- Jaroslaw Pasternak et al

-  Extend AG structure to phase rotation:			- 8 triplet FODO cells matched to decay channel
-  Add magnetic compression chicane:				- 2 periods, each 3 FODO cells

- 1.8x increase

## Rings

**Rings**

- S = solenoid, A = absorber, 36 cavities in blocks of 3

- Grahame Rees et al

-  Hybrid ring, using solenoids and dipoles
-  44m circumference: 18m straights, 4m bends
-  4m sections for injection and extraction
-  Initial results looking promising

## Working Group of F. Meot / CEA - DAPNIA

## Working Group of F. Meot / CEA - DAPNIA

**Design studies - Plans for the future **
** **
**a full design of a single- or double-RLA,**
**a full design of an FFAG ring - 6D tracking, DA, etc.**
**polytron scheme ?**
**converge on, finalise muSR design**
**in all cases, perform tracking simulations end to end**
***need develop simulation (including tracking) tools***
**"These acceleration systems are the largest cost items in the system" [DN,**
**Acceleration for the mu-storage ring neutrino-source]**
**prime goal : reduce costs**

## High Energy Frontier...

**Some time ago regarded by some people as science fiction, it must be noted that the advances in cooling theory and technology are so impressive as to ****consider this type of machine as a real possibility in the future****.**

***Muon Colliders***

## also : proton decay search, supernovae events solar and atmospheric neutrinos.

**300 MeV ************Neutrinos**
**small contamination from ********e****  (no K at 2 GeV!)**

**A large underground water Cerenkov (400 kton) **
**UNO/HyperK is best choice**
**also : proton decay search, supernovae events solar and atmospheric neutrinos.**

**Possible step 0: Neutrino SUPERBEAM**

**Fréjus underground lab.**

## + proton/H- driver 

**NUFACT (superbeam/neutrino factory)**

**isol production of **
**rare ions******

**+betabeam acceleration to ********(CERN)**

**4 MW target station **

**collection, horn**

**Cooling **

**muon acceleration and storage **

**+ proton/H****-**** driver **
**nuclear-synergy group **

**NA : BENE**

**Large cavern and UNO**

**proton driver  **

**Design studies (preliminary thoughts) **

**Driver  **********

**Post-accelerator**

**Mass separator**

**5 MW target**

**Scientific instrumentation**

## Many thanks to my European colleagues for their help to prepare this talk, in particular to:

**R. Aleksan**
**R. Garoby**
**Ch. Prior**
**R. Bennett**
**S. Gilardoni**
**B. Autin **
**R. Edgecock**
**F. Méot**
**M. Lindroos**
**and many others...**