DAEδALUS (Decay At rest Experiment for δcp At a Laboratory for Underground Science) has been proposed to measure the value of the CP violating phase delta through the oscillation of low energy muon anti-neutrinos to electron antineutrinos. With a single large detector, three accelerators at different distances enable the oscillation to be measured with sufficient accuracy. We have proposed the superconducting multi-megawatt DAEδALUS Supercinducting Ring Cyclotron (DSRC) as the means of producing the 800 MeV 12 mA protons required, through the acceleration of H2+, ions with highly efficient stripping extraction. The DSRC comprises twin ion sources and injector cyclotrons, followed by a booster. The injector cyclotron can also be used for a separate experiment, IsoDAR (Isotope Decay At Rest) in which low energy protons produce Lithium 8, and thus a very pure electron antineutrino source which can be used to measure, or rule out, short range oscillation to a sterile neutrino. We describe recent developments in the designs of the injector and the booster, and the prospects for the two experiments

Adelmann, A.

Alonso, J.R.

Barletta, W.A.

Barlow, Roger

Bungau, Adriana

Calabretta, L.

Calanna, A.

Campo, D.

Conrad, J.M.

Kolano, Anna

Méot, F.

Owen, H.L.

Shaevitz, M.H.

English

University of Huddersfield Repository

University of Huddersfield RepositoryBarlow, Roger , Bungau, Adriana, Kolano, Anna, Adelmann, A., Alonso, J.R., Barletta, W.A., Calanna, A., Campo, D., Conrad, J.M., Calabretta, L., Méot, F., Owen, H.L. and Shaevitz, M.H.High Power Cyclotrons for the Neutrino Experiments DAEδALUS and IsoDAROriginal CitationBarlow, Roger, Bungau, Adriana, Kolano, Anna, Adelmann, A., Alonso, J.R., Barletta, W.A., Calanna, A., Campo, D., Conrad, J.M., Calabretta, L., Méot, F., Owen, H.L. and Shaevitz, M.H. (2013) High Power Cyclotrons for the Neutrino Experiments DAEδALUS and IsoDAR. In: Proceedings of the 4th International Particle Accelerator Conference. IPAC 2013 . JACoW, Shanghai, China, pp. 446-448. ISBN 978-3-95450-122-9This version is available at http://eprints.hud.ac.uk/18438/The University Repository is a digital collection of the research output of theUniversity, available on Open Access. Copyright and Moral Rights for the itemson this site are retained by the individual author and/or other copyright owners.Users may access full items free of charge; copies of full text items generallycan be reproduced, displayed or performed and given to third parties in anyformat or medium for personal research or study, educational or not-for-profitpurposes without prior permission or charge, provided:• The authors, title and full bibliographic details is credited in any copy;• A hyperlink and/or URL is included for the original metadata page; and• The content is not changed in any way.For more information, including our policy and submission procedure, pleasecontact the Repository Team at: E.mailbox@hud.ac.uk.http://eprints.hud.ac.uk/HIGH POWER CYCLOTRONS FOR THE NEUTRINO EXPERIMENTSDAEδALUS AND ISODARR.J. Barlow∗, A. Bungau, A.M. Kolano, Huddersﬁeld University, Huddersﬁeld, UKF. Meot, BNL, Upton, Long Island, New York, USA,M. Shaevitz, Columbia University, New York, USA,L. Calabretta, INFN/LNS, Catania, Italy,J. R. Alonso, W. Barletta, A. Calanna, D. Campo, J. A. Conrad, MIT, Cambridge, Massachusetts, USA,A. Adelmann, PSI, Villigen, Switzerland,H. Owen, Manchester University, Manchester, UKAbstractDAEδALUS (Decay At rest Experiment for δcp At aLaboratory for Underground Science) has been proposedto measure the value of the CP violating phase δ throughthe oscillation of low energy muon antineutrinos to elec-tron antineutrinos. With a single large detector, three ac-celerators at different distances enable the oscillation to bemeasured with sufﬁcient accuracy. We have proposed themulti-megawatt DAEδDALUS Superconducting Ring Cy-clotron (DSRC) as the means of producing the 800 MeV12 mA protons required, through the acceleration of H+2ions with highly efﬁcient stripping extraction. The systemcomprises an ion source, a LEBT, and an injector cyclotronwhich feeds into the main ring. The injector cyclotron canalso be used for a separate experiment, IsoDAR (IsotropicDecay At Rest) in which low energy protons produce 8Li.This gives a very pure electron antineutrino source whichcan be used to measure, or rule out, short range oscil-lation to a sterile neutrino. We describe recent develop-ments in the designs of the injector and the booster, and theprospects for the two experiments.INTRODUCTION: THE CONCEPTSThe DAEδDALUS collaboration [1, 2] proposes to de-termine the value of the weak CP violating phase δ throughmeasurements of the oscillation νμ → νe at different dis-tances. Due to the size and cost of suitable neutrino de-tectors, this is achieved though having multiple low-energyneutrino sources. The current design has 800 MeV protonaccelerators at distances of 1.5, 8 and 20 km, with powersof 1.0, 1.6 and 4.8 MW. Each accelerator operates on a 20%duty cycle.A suitable high current proton cyclotron design has beenreported previously[3, 4, 5]. This paper reports on recentprogress[6, 7].CHOICE OF BEAM PARTICLE:H+2We propose to use H+2 ions, accelerated to a total energyof 1.6 GeV (800 MeV per proton). This ion is chosen toenable extraction from the cyclotron, where the orbits are∗R.Barlow@hud.ac.uktoo close to easily accomodate a septum, using a foil tostrip the electron.A second advantage over protons is the reduction in theeffects of space charge, which plays a pivotal role in the in-jector. Large-scale particle simulations [8] show that the in-jector cyclotron is space charge dominated but that a 5 mAbeam current can be extracted with tolerable beam losseson the septum. (By contrast, in the ring cyclotron, no spacecharge induced beam loss is observed during accelerationand extraction.) Space charge effects can be quantiﬁed us-ing the generalised perveance, K = qI2π0mγ3β3 showingthat H+2 has half the effect compared to protons.The use of H+2 imposes more stringent vacuum require-ments : below 10−8 rather than 10−7 torr, to reduce lossesfrom dissociation due to gas collisions. Also the highrigidity of the high energy, high mass particle means thathigh ﬁeld strengths are needed, requiring a superconduct-ing magnet.Lorentz stripping should not be a problem even in thesehigh ﬁelds, as the H+2 ion is considerably more tightlybound than the alternative H− ion (2.8 eV rather than0.7 eV). However not all H+2 molecules produced by theion source are in their ground state, and dissociation froman excited state requires appropriately less energy. Somestates are long lived (compared to the time spent in the ac-celerator) and could be Lorentz stripped in the 6T magneticﬁeld, which would produce unacceptable beam losses. Wedo not know what mixture of states is produced by the ionsource, and we are starting an experimental programme tomeasure this. If there is a problem then the H+2 can becooled by mixing with molecules of an inert neutral gas,such as Helium. This is being investigated using the ORNLfacility.There is also a possibiity that when the H+2 interacts inthe foil it produces H0 - neutral hydrogen atoms, whichwould also result in losses.Assumng a phase acceptance of ±10◦, and a factor of2 due to bunching in the LEBT, the source is required todeliver 50 mA of H+2 . The Versatile Ion Source (VIS),designed and built at INFN-LNS (Catania) should achievethis. It is an off-resonance 2.45 GHz microwave dischargesource[9] and can produce beams with emittance of orderMOPFI071 Proceedings of IPAC2013, Shanghai, ChinaISBN 978-3-95450-122-9446Copyrightc ○2013byJACoW—ccCreativeCommonsAttribution3.0(CC-BY-3.0)04 Hadron AcceleratorsA13 Cyclotrons0.1 π mm mrad. We have currently extracted 20 mA ofH+2 from this source in early tests, and work is ongoing toincrease this number.The LEBT that takes the beam from the ion source com-prises two solenoids, separated by a Wien ﬁlter and a colli-mator slit to select theH+2 ions, and focussing quadrupoles.This section also includes an RF buncher for longitudinal-compression, to increase capture efﬁciency. Experimentaltests with the source, and the matching of the beams fromit, are currently under way at BEST cyclotrons, in Vancou-ver.THE INJECTORThe DAEδDALUS Injector Cyclotron (DIC) will accel-erate 5 mA of H+2 ions up to 60 MeV/amu. This is an or-der of magnitude more than current commercial cyclotrons,giving it a potential application as a productive source ofmedical isotopes.It has 4 sectors, an outer diameter of 6.2 m, is 2.7 mhigh and weighs 450 tons. The ﬁeld, from a conventionalmagnet, increases from 1.075 to 1.16 T.Injection will be done using a spiral inﬂector. Bunchescan be extracted conventionally, as the turn by turn separa-tion at extraction is 2 cm, using two electrostatic deﬂectorsand two magnetic channels. Four 49.2 MHz (6th harmonic)double-gap RF cavities accelerate the bunches in 107 turns.The isochronism is better than 5× 10−4.The effect of space charge has been studied using theOPAL code[10]. Because of these issues, we have in-creased the proposed injection energy from 30 to 70 keV(35 keV/amu), giving the same generalised perveance ascommercial cyclotrons.Figure 1: The InjectorTHE MAIN CYCLOTRONThe DAEδDALUS Superconducting Ring Cyclotron(DSRC), is the main component of the accelerator system.Details of the design have changed considerably since pre-vious studies[3, 4, 5] and may change further as the designis optimised.Eight superconducting sector magnets are used, withcurrent densities of 3400A/cm2. The enormous structuralforces have been analysed in detail using OPERA, andstainless steel plates are used to connect opposite segments.The cryostat is made or iron and stainess steel, with wallsof varying thickness. The magnetic is similar to the ex-isting RIKEN SRC, hence the parameters are in generalcreditable.Four single-gap copper cavtities are used, 3m high and8.8m long, operating at 49.2 MHz (6th harmonic) with aQ value of 37,500, giving an acceleration from 2.0 to 4.0MV per turn. These cavities are similar to those of the PSIcyclotron and their parameters are hence also creditable.It may be possible to supplement these by two double-gapcavities, and this option is being considered. These are in-cluded in the design shown in Figure 2. Injection uses ﬁvemagnetic channels and an electrostatic deﬂector. Extrac-tion is by means of a thin (2mg/cm2) pyrolitic graphitefoil, a few cm2 in size. Electrons are stopped on a coppershield. Any neutral hydrogen produced can be extractedsafely. The pulse width has to be kept below 1 ms to en-sure the foil temperature is kept below 2500 K. Based onthe experience of SNS we anticipate foil lifetimes of sev-eral months.Isochronicity of the design is adequate, and focussingis sufﬁcient in both planes. The Walkinshaw resonance iscrossed rapidly, and only once, and should not lead to beamlosses.Figure 2: The main cyclotronThe requirements for this machine are similar to thosefor ADS systems, and thus have a very large potential ap-plication.ISODARIn addition to the main DAEδALUS experiment, the lowenergy injector cyclotron could be used for some inter-esting neutrino experiments [11, 12]. With careful targetProceedings of IPAC2013, Shanghai, China MOPFI07104 Hadron AcceleratorsA13 CyclotronsISBN 978-3-95450-122-9447 Copyrightc ○2013byJACoW—ccCreativeCommonsAttribution3.0(CC-BY-3.0)design and optimisation, low energy protons can produceshort lived isotopes which rapidly β decay, producing anelectron antineutrino. As the isotope has time to stop inthe target, the decay occurs at rest in the lab and the dis-tribution produced is isotropic. We propose a 60 MeV,5mA, 600 kW H+2 accelerator, which is about a factor of10 more intense than cyclotrons currently used for medicalisotope production. A 9Be target produces neutrons, whichare moderated by D2O and interact in a 7Li sleeve, whichwill produce 8Li, giving 2.6 1022νe per year with an aver-age energy of 6.4 MeV. 14.6 antineutrinos are produced per1000 protons. 90% of these are produced in the sleeve, and10% in the beryllium target. Production of neutrinos, andantineutrinos from other isotopes, is negligible.A speciﬁc package for low energy proton interactionsis necessary and we have used the QGSP-BIC-HP physicspackage in GEANT4[13]. Further details are presented inanother contribution to this conference[14]The neutrinos can be measured up to 20m away usingthe clean and characteristic inverse beta decay signal, andprovide a deﬁnitive answer on the existence or otherwiseof sterile neutrinos which have been proposed as a possiblesolution to the ’reactor anomaly’. It would also provide alarge sample of νee− scattering events, which could pro-vide a signature for dark matter candidates . The experi-ment needs a detector of size of order 1 kton. This could beKAMLAND, and the accelerator could be installed in theKamioka mine. Access through the existing tunnel requiresthe cyclotron to be taken in parts, and the enclosing copperliner will have to be cut in two and welded in situ, which isproblematic but possible. The SNO+ detector is also underconsideration.PROSPECTS FOR DAEδALUSThe investigation of CP violation in the neutrino sector isone of today’s greatest issues in particle physics, as a key tobig bang cosmology. DAEδDALUS presents a unique wayto probe this question, and we are vigorously arguing itscase with our colleagues, with presentations at many work-shops, conferences and seminars.We see development in four stages, of which the ﬁrst,testing of the Ion Source, is already under way. The secondis the construction of the injector. We would then constructone DSRC, and ﬁnally another two. Each step would notmerely be a technical development, but would bring a fullphysics programme.The developments in accelerator technology would alsobring strong industrial beneﬁts, through improved medicalisotope production and by building the accelerators neededfor ADSR/Thorum fuelled nuclear power.The design is still evolving as our understanding grows,with many possibiltiies not discussed here also being con-sidered. The DAEδDALUS collaboration is a vigorous in-ternational and cross-disciplinary team: great progress isbeing made, and is set to continue.REFERENCES[1] J. M. Conrad, “The DAEδDALUS Experiment’ Proc. XXIVInt Conf on Neutrino Physics and Astrophysics, Athens,Greece (2010) ’[2] R. Barlow “DAEδALUS: Using multiple accelerators to de-termine CP violation in the neutrino sector” Proc. EPS HEPPConference, Grenoble, France (2011)[3] L. Calabretta et al., “A Superconducting cyclotron to deliverhigh intensity proton beams” Proc. EPAC 2000, Vienna Aus-tria, THP6B02, (2000)[4] L.Calabretta et al., ‘A Multi Megawatt Cyclotron Complexto Search for CP Violation in the Neutrino Sector” Proc. Cy-clotron’10, Lanzhou, China (2010)[5] A. Calanna et al., “A Multi Megawatt Ring Cyclotron toSearch for CP Violation in the Neutrino Sector” Proc. PAC2011, New York, USA, (2011)[6] J. Alonso et al., “High Current H+2 Cyclotrons for NeutrinoPhysics: the IsoDAR and DAEδALUS Projects” October2012 arXiv PDF[7] M. Abs et al., “Multimegawatt DAEδDALUS Cyclotrons forNeutrino Physics” arXiv 1207.4895 (2012)[8] J. J. Yang et al., “Beam Dynamics Simulation for the HighIntensity DAEALUS Cyclotrons” Nucl. Instr. & Meth. 704,84 (2013)[9] F. Mainone et al.. ‘Status of the Versatile Ion Source (VIS)’in Proc. Eur. Part. Acc. Conf. EPAC08, Genoa, Italy. (2008)[10] A. Adelmann, C Kraus, Y Ineichen and J J Yang ‘The OPALFramework’, Tech-Rep PSI-PR-08-02 (2008)[11] A. Bungau et al., ‘Proposal for an Electron AntineutrinoDisappearance Search Using High-Rate 8Li Production andDecay’ Physical Review Letters , 109 (14), p. 141802. (2012)[12] A. Adelmann et al. “ Cost-effective Design Options for Iso-DAR” arXiv:1210.4454v1 (2012)[13] S. Agostinelli et al., Nicl. Instrum. Methods. Phys.Pes. A506 250 (2003)[14] A. Bungau et al., “Optimisation Studies of a High In-tensity Electron Antineutrino Source” These proceedings,MOPFI073MOPFI071 Proceedings of IPAC2013, Shanghai, ChinaISBN 978-3-95450-122-9448Copyrightc ○2013byJACoW—ccCreativeCommonsAttribution3.0(CC-BY-3.0)04 Hadron AcceleratorsA13 Cyclotrons

A Multi Megawatt Cyclotron Complex to Search for CP Violation in the Neutrino Sector”

A Multi Megawatt Ring Cyclotron to Search for CP Violation in the Neutrino Sector”

A Superconducting cyclotron to deliver high intensity proton beams”

DAEδALUS: Using multiple accelerators to determine CP violation in the neutrino sector”

High Power Cyclotrons for the Neutrino Experiments DAEδALUS and IsoDAR Original Citation Barlow,

Optimisation Studies of a High Intensity Electron Antineutrino Source” These proceedings,

High Power Cyclotrons for the Neutrino Experiments DAEδALUS and IsoDAR

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