1. UK Neutrino Factory Conceptual Design
Stephen Brooks, Christopher Prior
ASTeC Intense Beams Group, RAL
Physics Motivation
The discovery of neutrino masses requires the standard model of physics to be modified. Measuring their mass precisely is one of the few ways a new theory can be constrained. The mass differences between neutrino flavours cause oscillation from one type to another with a wavelength proportional to D(Mass2)*(Baseline)/(Energy), meaning baselines in the >1000km range are needed for the best detectable >10GeV neutrinos.
Staging Scenario (UK Case)
The neutrino factory complex could be built up in stages: upgrades to the ISIS proton synchrotron at RAL could supply both the neutrino factory and enhanced flux for existing neutron and muon science. The neutrino factory could itself be upgraded to a multi-TeV muon collider, which would have high-energy particle physics capabilities surpassing the LHC and ILC in several areas.
This diagram shows the main subsystems of the neutrino factory. Four areas are highlighted in which the UK will perform key technology demonstrations within the next five years.
180MeV H− Linac
Proton Driver Front End
Proton Driver
Required energy 5-15GeV
Repetition rate 50Hz
Mean power 4-5MW
3-6 bunches formed
Compressed to 1-3ns RMS  Peak power 8-60TW
972MHz Side-Coupled Linac (SCL)
to 180MeV
324MHz Drift Tube Linac (DTL)
to 90MeV
Beam Chopper
RFQ
to 3MeV
LEBT
at 35keV
H− Ion
Source
Achromat for removing beam halo
Proton Driver Front-End Test Stand (FETS)
Two Stacked Proton Synchrotrons (full energy)
6GeV
78m mean radius
Each operating at 25Hz, alternating for 50Hz total
See also:
FETS poster
A prototype of the first stages in a high power proton driver is being constructed at RAL.
Muon Ionisation Cooling Experiment (MICE)
This project will construct a fully-engineered cooling cell with diagnostics and test its performance using muons extracted from the ISIS beam.
Stripping Foil
(H− to H+/protons)
Two Stacked Proton Synchrotrons (boosters)
1.2GeV
39m mean radius
Both operating at 50Hz
Present
2010s
2020s
2030s
Proton Power
150kW
1MW  2.5MW  5MW
Neutron Science
ISIS
ISIS MW Upgrades
ESS-class Machine
Neutrino Physics
Neutrino Factory
Fundamental & Higgs Physics
Muon Collider
Solenoidal Decay Channel
(in which pions decay to muons)
Muon Cooling Dogbone
Solid Target R&D Programme
Pictured above is a test being conducted at RAL of the durability of wire samples of target materials under thermal shocks comparable to those in the real NF target, which are induced by an intense pulsed current.
See also:
MICE poster
RF Phase Rotator
Residual proton Beam Dump
Tungsten target enclosed in 20T solenoid
(produces pions from protons)
Plan view of the new accelerators superimposed on the RAL and Harwell site.
FFAG Electron Model of Muon Acceleration (EMMA)
Dogbone Recirculating Linac (RLA)
5½ pass,
2-13GeV
A new type of accelerator called a non-scaling FFAG is used in the final muon acceleration stages. The prototype EMMA is scheduled for construction at Daresbury.
See also:
EMMA
poster
Muon Decay Ring
(muons decay to neutrinos)
Solenoidal Muon Linac 0.2-2GeV
Near Detector
R110
R109
Far Detector 1
Far Detector 2
Neutrino Factory
FFAG 2
25-45GeV
FFAG 1
13-25GeV
To Far Detector 1
To Far Detector 2
~300m below ground