Continuation of UK participation in the international Muon Ionization Cooling Experiment (MICE)

Lead Research Organisation: Imperial College London
Department Name: Dept of Physics

Abstract

Neutrinos are three different but related particles; their ability to turn into each other has given physicists their first glimpse of the physics which they know must lay beyond the Standard Model. Investigation of the physics which underlies their properties will: deepen our understanding of how the Universe developed after the Big Bang; how the current asymmetry between matter and anti-matter developed from a situation where they were created in equal amounts in the Big Bang; and help us to understand what happens when a supernova explodes showering the cosmos with the heavy elements necessary for planets and life itself to form.
In order to understand their properties, we must build an accelerator capable of creating neutrinos in immense numbers. They must have energy between well-defined limits and the mixture of different types must be very precisely known. Such a facility, known as the Neutrino Factory, would be revolutionary and to build one is a challenging project, both from the point of view of the particle detectors which must be built, and the engineering problems which must be overcome. This programme needs a world-wide collaboration, but it is one in which physicists and engineers from the UK are playing a leading role.

Neutrinos are created from a beam of muons and the muons themselves are produced from the decay of pions produced by the collision of protons with a metal target. A machine to make an intense beam of neutrinos needs to take the beam of muons, which is large and diverges rapidly, and reduce its size and divergence. The resulting beam can be accelerated, stored and when it decays produces an intense beam of neutrinos. The muons only live for 2.2 microseconds when at rest, and even when they are accelerated and their lifetime is extended by the effect of relativity, there is little time to manipulate the muons so that they are in a state to be accelerated.

MICE is an international collaboration based at the Rutherford Appleton Laboratory in Oxfordshire, which uses a beam of muons created by the ISIS accelerator and aims to show that it is feasible to create such an intense beam. It will do this by creating a beam of muons of much lower intensity and tracking each one individually through one part of the system which has been designed to perform this beam compression at the Neutrino Factory. This process where the random sideways motions of the muons are reduced and we are left with the longitudinal motion is referred to as cooling the beam; the system which performs the cooling is known as the cooling channel.

The first stage was to build a system capable of producing a muon beam whose size and divergence could be adjusted before it enters the cooling channel. This was completed last year and measurements have been made to show that the beam has the flexibility and intensity for MICE to perform the required measurements.
The second stage is to finish construction of the cooling channel itself and to provide a system to measure very accurately the position and momentum of each muon before and after it has passed through the cooling channel. By looking at many muons produced in many different conditions, it will be possible to determine how much cooling has been produced by the channel. In the channel itself the muons will be slowed by passing through a suitable material, such as liquid hydrogen, liquid helium or lithium hydride. As they slow they lose momentum both longitudinally and transversely to the beam axis. Then they are accelerated with high field radio frequency cavities, replacing only the longitudinal momentum.

This experiment which is pushing the boundaries of what is possible with materials, magnets and cooling technologies, represents a collaboration between particle physicists, and accelerator physicists and will demonstrate the UK's ability to host an experiment at the forefront of science and engineering.

Planned Impact

MICE is a large, capital construction project. A significant part of the investment in the project has been used to source products and materials in British industry. For example, of the £4.50M non-staff spend in Phase I of the project, approximately £4.09M was used to source materials and equipment in the UK.

The UK is responsible for the procurement of the focus-coil modules that focus the muon beam at the centre of the liquid-hydrogen absorbers. Each focus-coil module contains two coils capable of producing a field of 5 T on axis. The coils will be kept cold using closed-cycle refrigerators (cryocoolers), a novel technique requiring considerable development. TESLA Engineering based in Surrey won the contract to provide the focus coils. Engineers and physicists from Technology Department at RAL and the University of Oxford are working with TESLA to ensure that the design and its implementation will yield a magnet fit for purpose in MICE. The expertise gained by TESLA will be applicable in the construction of magnets for other applications. In addition, the UK is responsible for the provision of liquid hydrogen to each of the three absorber-modules. The hydrogen delivery system uses state-of-the-art hydride-bed technology and liquefaction is performed with cryocoolers. The development of the systems for MICE will be carried out in collaboration with industry to the benefit of the hydrogen economy.

The MICE programme is varied, encompassing the development of numerical methods and simulation techniques, the development of accelerator hardware (from conventional transfer lines to the development of novel superconducting magnets), the construction of a novel, pion-production target, the development of hydrogen-handling systems, the provision of RF power, and the construction of state of the art diagnostics. Further, the implementation of the large and complicated project has allowed members of the collaboration to develop project management and integration engineering skills.

MICE is an integral part of the Proton Accelerators for Science and Innovation initiative, putting the UK firmly at the heart of the community that seeks to develop the technology required to produce high intensity muon beams suitable for use in the Neutrino Factory and Muon Collider. MICE has created a UK community capable of delivering large and complex projects in an international environment.

Substantial contributions to the experiment in equipment, personnel, and intellectual input are being made by the international collaboration. To date, the international collaboration has provided the muon decay solenoid, beam-line instrumentation (scintillators and scintillating-fibre based beam-position monitors), three time-of-flight hodoscopes, two Cherenkov detectors, a lead-scintillator pre-shower detector, a prototype of the Electron Muon Ranger, the tracker readout and cryogenic systems, three high-power RF amplifiers, and the data-acquisition system. Over the period of the award, the international collaboration will complete the time-of-flight and calorimeter systems and provide the spectrometer solenoids, the liquid-hydrogen absorbers, and the RF-cavity/coupling-coil modules. The total value of these contributions, through hard to estimate, is in excess of £25M.

By making a success of the MICE project, the UK has gained substantial influence in the international Neutrino Factory community. The leverage opportunity for the future will be to forge appropriate partnerships with those laboratories or collaborations wishing to develop the Neutrino Factory and Muon Collider as options for the field. This is being taken forward through the EC FP7 Preparatory Phase Project TIARA in which funds have been secured to turn the infrastructure that supports the MICE experiment into the Ionization Cooling Test Facility (the ICTF).

Publications

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Adams D (2015) Electron-muon ranger: performance in the MICE muon beam in Journal of Instrumentation

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Adams D (2013) Characterisation of the muon beams for the Muon Ionisation Cooling Experiment in The European Physical Journal C

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Adams D (2016) Pion contamination in the MICE muon beam in Journal of Instrumentation

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Adey D (2017) Overview of the Neutrinos from Stored Muons Facility - nuSTORM in Journal of Instrumentation

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Apollonio M (2012) The International Design Study for the Neutrino Factory in Nuclear Physics B - Proceedings Supplements

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Asfandiyarov R (2019) MAUS: the MICE analysis user software in Journal of Instrumentation

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Bayliss V (2019) The liquid-hydrogen absorber for MICE in IOP Conference Series: Materials Science and Engineering

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Bayliss V (2018) The liquid-hydrogen absorber for MICE in Journal of Instrumentation

 
Description Muons are fundamental particles. Their mass is 200 times that of the electron. They are unstable and decay to produce electron and muon neutrinos. These properties make muons the ideal as a source of neutrinos for beams designed to serve experiments that will be able to study the properties of the neutrino with exquisite precision. In addition, muon may be accelerated to very high energy, allowing lepton-antilepton collisions at energies much larger than can be achieved using electrons to be conceived.
Exploitation Route We have developed and characterised an experiment designed to demonstrate that the size of a beam of muons can be controlled using a process known as ionization cooling. The data acquired during the operation of the experiment is being prepared for publication. Over the past year the seminal demonstration of ionisation cooling has been published in Nature. The result is important since it provides the basis on which future development of muon beams of high brightness can be developed. In addition it places Imperial and the UK in an excellent position of leadership in the field.
Sectors Healthcare,Other

URL https://micewww.pp.rl.ac.uk/projects/mice/wiki/For_the_public
 
Description Various publications and proceedings have used the results. The progress of the MICE experiment and developments such as nuSTORM build on the achievements. The publication of the demonstration of ionisation cooling in Nature was fortuitously timed during the revision of the European Strategy for Particle Physics. The updated ESPP includes the recommendation that muon-beam R&D be pursued. This is of value to the development of the activity in the UK and at Imperial. The opportunity to develop the accelerator R&D activity at Imperial through the development of novel techniques for radiobiology and for clinical application has arisen out of our work on proton-accerator design and component design and development. This has led to the formation of the interdisciplinary Centre for the Clinical Application of particles which is a collaboration of personnel the Faculty of Medicine, the Imperial Academic Health Science Centre, the Department of Physics, the Imperial CRUK Cancer Centre, the Institute of Cancer Research, the John Adams Institute and the Oxford Institute for Radiation Oncology. The centre-piece of the Centre's R&D programme, the Laser-hybrid Accelerator for Radiobiological Applications, builds on the groups success in MICE.
Sector Other
Impact Types Cultural,Societal

 
Description Development of proton and muon accelerators for science and innovation 
Organisation STFC Laboratories
Country United Kingdom 
Sector Public 
PI Contribution Development of accelerators for pulsed high-power proton sources, study of beam loss in synchrotron, design of FFAG muon ring for neutrino cross section measurements. Development of beam delivered to MICE at RAL. Organisation of Proton Accelerators for Science and Innovation workshops.
Collaborator Contribution Provision of infrastructure and expertise in the above. Collaboration in organisation of the Proton Accelerator for Science and Innovation workshops.
Impact Joint proposals for research work. Joint publications, listed elsewhere.
Start Year 2020
 
Description Development of proton and muon accelerators for science and innovation 
Organisation Science and Technologies Facilities Council (STFC)
Department ISIS Neutron and Muon Source
Country United Kingdom 
Sector Academic/University 
PI Contribution Development of accelerators for pulsed high-power proton sources, study of beam loss in synchrotron, design of FFAG muon ring for neutrino cross section measurements. Development of beam delivered to MICE at RAL. Organisation of Proton Accelerators for Science and Innovation workshops.
Collaborator Contribution Provision of infrastructure and expertise in the above. Collaboration in organisation of the Proton Accelerator for Science and Innovation workshops.
Impact Joint proposals for research work. Joint publications, listed elsewhere.
Start Year 2020
 
Description MICE beam line, dipping target and beam line, tracker and MICE Step I data analysis 
Organisation International MICE Collaboration
Country Global 
Sector Academic/University 
PI Contribution Construction of, and control systems for the MICE target, construction of the MICE Muon Beam. Construction, commissioning with cosmics, of the MICE tracker. Analysis of data from the MICE experiment and preparation for publication.
Collaborator Contribution Contributions to the MICE dipping target, the decay solenoid and conventional magnet systems. Readout for the tracker and contributions to the commissioning. Development of algorithms for the analysis of MICE data and publication.
Impact Publications in refereed journals (2); many talks at international conferences.
 
Description Hands-on schools engagement programme at Neutrino 2016 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact School pupils were invited to activities at the Wohl Reachout Lab at Imperial for carious hands-on activities on astro-physics and particle physics. The event was organised in conjunction with the 2016 Neutrino conference in South Kensington.
Year(s) Of Engagement Activity 2016
 
Description MICE mural, competition for schools 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Schools across the UK were contacted by Imperial Schools Liaison and the IoP Schools Liaison to invite entries for a mural to be painted on the MICE shielding wall. The schools were invited to events at RAL to promote the competition. Prizes for the winners were presented by Brian Cox and Art McDonald (Nobel Laureate) at the public lecture at the Neutrino 2016 conference in London.
Year(s) Of Engagement Activity 2016
 
Description Public Lecture at Neutrino 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Brian Cox presented the public lecture to a packed audience (750, the maximum the Hall could accommodate) at the Neutrino 2016 conference in South Kensington in Jun2016.
Year(s) Of Engagement Activity 2016
 
Description Public engagement at the time of the publication of the seminal MICE demonstration of ionisation cooling in Nature 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Working with CERN, Fermilab, the STFC and others a press release was prepared to mark the publication of the seminal demonstration of ionisation cooling in Nature.
Year(s) Of Engagement Activity 2020
URL https://micewww.pp.rl.ac.uk/projects/mice/wiki/For_the_public