H' Haseroth

1

• Overview of the CERN Neutrino Factory Machine
  Studies
• H. Haseroth
• for the
• Neutrino Factory Working Group

2

• The Basic Concept of A
• Neutrino Factory
• Proton driver
• High-power proton beam onto a target
• System for collection of the produced pions and
  their decay products, the muons.
• Energy spread and transverse emittance have to be
  reduced phase rotation and ionisation cooling
• Acceleration of the muon beam with a linac and
  RLAs (Recirculating Linear Accelerators)
• Muons are injected into a storage ring (decay
  ring), where they decay in long straight sections
  in order to deliver the desired neutrino beams.

3
Goal 10E21 muons/year
4

• The original idea as expressed by Kurt had the
  goal of having ready two future options for CERN
  at the time when LHC is running CLIC and the
  Neutrino Factory.
• CLIC had been started much earlier and with this
  argument a distribution of RD resources of 1/3
  for the NF and 2/3 for CLIC has been justified.
• Formally we are not too far away from the 1/2
  ratio (of course we are lower!). It must,
  however, be remembered - especially when we are
  compared to the US - that in our case the proton
  driver (SPL and accumulator / compressor rings)
  is counted as "NF activity". The proton driver is
  a substantial element in our CERN scenario. In
  the US this is not really counted as NF activity,
  but as a mere and simple upgrade of their
  existing machines.

5

• Activities concerning the Proton Driver
• (Main CERN Actors with substantial fraction of
  their time)
• SPL (Garoby, Lombardi, Vretenar)
• Accumulator Ring (Schonauer, Metral, Cappi)
• Compressor Ring (Schonauer, Metral, Cappi)
• Fast cycling Synchrotrons (Schonauer)

6
Schematic Layout of the SPL (4 MW of Beam Power)
7
The SPL on the CERN site
8
RAL Accumulator (1)
2.2 GeV RAL Accumulator
ISR tunnel
Mean ring radius150 m
9
RAL Accumulator CERN Compressor (2)
Accumulator Compressor
Accumulator
Compressor
in ISR Tunnel
10
33 Hz Operation with 3.41 1014 p/p End of
Compression (Phase painting /- 90 deg)
10 turns
8 turns
11

• Non Proton Driver Activities
• (Main CERN Actors with substantial fraction of
  their time)
• Target and collection (magnetic horn) work, i.e.
  simulations of pion production, simulations of
  capture and experimental work on target issues
  (Ravn, Lettry, Volker, Maugain)
• Simulation of the phase rotation (energy
  reduction), of the cooling channel and of the
  acceleration in the first linac (Lombardi, Hanke,
  Holzer)
• Simulation the RLAs (Recirculating Linear
  Accelerators) and of the Decay Ring (Keil,
  Verdier)
• Work by ST for layout on the site (Poehler)
• Detector locations being investigated (Wenninger)

12
(No Transcript)
13
(No Transcript)
14
Principle of Ionisation Cooling
Ideally a muon is stopped by passing through some
material and is being accelerated in the forward
direction. Because it would have decayed in the
meantime, only some reduction in longitudinal and
transverse momentum is applied. The longitudinal
momentum is being replaced again by RF
acceleration. Problem Heating because of
multiple scattering.
15
Why a compressor ring? Why bunch rotation? (146
bunches during 3.3?s)
Pions (used)
Pions wasted
Protons after compressor
?p
Protons in accumulator
Muons after phase rotation
Pions (used)
Muons after drift
10 ns
10 ns
1 ns
10 ns
Works only if ? ? 1 (RF gradients)
Works only if ? lt 1
1 ns
? t
Pions after target
16
Asymmetric 88 MHz cavities
17

• Layout of 40/80 MHz Cooling Channel

beam in
beam out
18
Parameters of Recirculating Linacs (RLAs)
Parameters of Decay Ring
19
Preliminary Layout of Neutrino Factory
20
(No Transcript)
21

• Arguments for an International Muon Cooling
  Experimental Demonstration
• There are quite different opinions about the
  necessity to do a cooling experiment, however,
  the majority believes strongly that there is a
  need to demonstrate that ionisation cooling is
  indeed technically feasible. Some people feel
  that even the relevant programs need checking by
  experiments. One remark to answer criticism like
  "we know Moliere scattering and Maxwell's laws"
  is that in spite of knowing Maxwell's laws and
  the properties of superconducting cable one has
  built not only one but several magnet prototypes
  for the LHC. Muon ionisation cooling is by no
  means more trivial.
• As a by-product of the discussions in the context
  of the cooling experiment several new ideas came
  already up, which were the result of stimulating
  exchange of ideas, not limited to the SPL and the
  target
• The idea of "Beta - beams", i.e production of
  neutrino beams by decay of radioactive isotopes
• Very important findings about the H2 absorber
  heat load due to electron beams from the
  cavities.

22

• A possible (poor man's ) Muon Cooling Experiment
• The main hardware is composed of the following
  items
• RF cavities
• RF transmitters, modulators and charging
  supplies
• Cavity sc solenoids
• Hydrogen absorbers
• Measuring lines at input and output including sc
  solenoids and data acquisition

23
(No Transcript)
24

• To minimise the cost, the following distribution
  of hardware contributions is envisaged (very
  personal and provisional!)
• 1) One 4 cell cavity from the US collaboration
  (LBNL)
• 2) CERN (One rf transmitter refurbished with
  pieces from Linac1, one spare borrowed. Upgrading
  of power with special tube (old 516) needed.
  Russian manpower is sought to help)
• 3) Swiss confederation, RAL, EU money?
• 4) American / Japanese collaboration (IIT et al.)
• 5) Collaboration of different physics institutes
  (V. Palladino)
• a Muon Beam (PSI or RAL)

25
Cooling experiment at PSI?