H. Haseroth Friday, August 31, 2001 MUG Meeting 1 Overview of the CERN Neutrino Factory Machine Studies H. Haseroth for the Neutrino Factory Working Group

H. Haseroth Friday, August 31, 2001 MUG Meeting 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.

H. Haseroth Friday, August 31, 2001 MUG Meeting 3 Goal: 10E21 muons/year

H. Haseroth Friday, August 31, 2001 MUG Meeting 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 R&D 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.

H. Haseroth Friday, August 31, 2001 MUG Meeting 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)

H. Haseroth Friday, August 31, 2001 MUG Meeting 6 Schematic Layout of the SPL (4 MW of Beam Power)

H. Haseroth Friday, August 31, 2001 MUG Meeting 7 The SPL on the CERN site

H. Haseroth Friday, August 31, 2001 MUG Meeting 8 RAL Accumulator (1) ISR tunnel 2.2 GeV RAL Accumulator Mean ring radius=150 m

H. Haseroth Friday, August 31, 2001 MUG Meeting 9 RAL Accumulator & CERN Compressor (2) Accumulator & Compressor Accumulator Compressor in ISR Tunnel

H. Haseroth Friday, August 31, 2001 MUG Meeting Hz Operation with p/p : End of Compression (Phase painting +/- 90 deg) 8 turns 10 turns

H. Haseroth Friday, August 31, 2001 MUG Meeting 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)

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H. Haseroth Friday, August 31, 2001 MUG Meeting 14 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. Principle of Ionisation Cooling

H. Haseroth Friday, August 31, 2001 MUG Meeting 15 pp  t Why a compressor ring? Why bunch rotation? (146 bunches during 3.3  s) Pions (used) 10 ns 1 ns 10 ns Protons in accumulator Pions wasted Pions (used) Protons after compressor Pions after target Muons after drift Muons after phase rotation 1 ns Works only if  < 1 Works only if   1 (RF gradients)

H. Haseroth Friday, August 31, 2001 MUG Meeting 16 Asymmetric 88 MHz cavities

H. Haseroth Friday, August 31, 2001 MUG Meeting 17 Layout of 40/80 MHz Cooling Channel beam in beam out

H. Haseroth Friday, August 31, 2001 MUG Meeting 18 Parameters of Recirculating Linacs (RLAs) Parameters of Decay Ring

H. Haseroth Friday, August 31, 2001 MUG Meeting 19 Preliminary Layout of Neutrino Factory

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H. Haseroth Friday, August 31, 2001 MUG Meeting 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 H 2 absorber heat load due to electron beams from the cavities.

H. Haseroth Friday, August 31, 2001 MUG Meeting 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

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H. Haseroth Friday, August 31, 2001 MUG Meeting 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)

H. Haseroth Friday, August 31, 2001 MUG Meeting 25 Cooling experiment at PSI?