ESSνSB – Far Detector and Underground Site nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University Tord Ekelöf, Uppsala Univerisity

Deriving the optimal base line for the ESS SuperBeam for CP violation discovery nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 2 Full GLoBES simulations with 15% ν cross-section and syst. errors by Enrique Fernandez - The fraction of the full δ CP range 0 o -360 o within which CP violation can be discovered as function of the baseline length in km for proton linac energies 2, 2.5 and GeV. - The lower (upper) curves are for CP violation discovery at 5σ (3σ ) significance. Maximum CPV sensitivity at the 2 nd oscillation maximum Garpenberg mine 1 st osc max 2ns osc max 3 rd osc max

The signifiance in terms of number of standard deviations with which CP violation could be discovered for δ CP -values from -180 to +180 degrees for 2.0 GeV protons in 10 years nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 3

CPV Discovery Performance for Future SB projects, MH unknown, Snowmass comparison nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 4 IDS-NF Neutrino Factory NuMAX are: 10 kton magnetized LAr detector, Baseline is 1300 km, and the parent muon energy is 5 GeV LBNO100: 100 kt LAr, 0.8 MW, 2300 km Hyper-K: 3+7 years, 0.75 MW, 500 kt WC LBNE-Full 34 kt, 0.72 MW, 5/5 years ~ 250 MW*kt*yrs. LBNE-PX 34 kt, 2.2 MW, 5/5 years ~750 MW*kt*yrs. EUROSB: 2+8 years, 5 MW, 500 kt WC (2.0 GeV, 360 (upper)/540 km (lower)) 2020 currently running experiments by 2020 Pilar Coloma ESS 2.0 GeV

CPV Discovery Performance for Future SB projects, MH unknown, Snowmass comparison nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 5 IDS-NF Neutrino Factory NuMAX are: 10 kton magnetized LAr detector, Baseline is 1300 km, and the parent muon energy is 5 GeV LBNO100: 100 kt LAr, 0.8 MW, 2300 km Hyper-K: 3+7 years, 0.75 MW, 500 kt WC LBNE-Full 34 kt, 0.72 MW, 5/5 years ~ 250 MW*kt*yrs. LBNE-PX 34 kt, 2.2 MW, 5/5 years ~750 MW*kt*yrs. ESSnuSB, in the figure called EUROSB: 2+8 years, 5 MW, 500 kt WC (2.5 GeV, 360 (upper)/540 km (lower)) 2020 currently running experiments by 2020 Pilar Coloma ESS 2.5 GeV

Mass hierarchy determination for different base lines with ESS νSB during 10 years nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 6 The significance in mass hierarchy determination as function of δ CP for different base line lengths (Enrique Fernandez) Measurements with atmospheric neutrinos will further improve this performance

nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 7 7 A Megaton water Cherenkov detector to study; Neutrinos from accelerators (Super Beam) but also Supernovae neutrinos (burst + "relics"), Solar Neutrinos, Atmospheric neutrinos, Geoneutrinos Proton decay up to ~10 35 years life time. All these other measurements require the detector to be shielded by ~1000 m rock from cosmic ray muons To measure low energy neutrinos a large water Cherenkov detector is required (low neutrino cross section) and sufficient (few inelastic events)

A distinct feature of ESSnuSB is its low beam energy. One implications of this is that the second oscillation maximum will be located at not too large a distance from the source. Several mines located at this distance from ESS/Lund are available (not so for LBNE and HyperK) nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 8

9 Garpenberg Mine Distance from ESS Lund 540 km Depth 1232 m Truck access tunnels Two ore hoist shafts A new ore hoist schaft is planned to be ready i 1 year, leaving the two existing shafts free for other uses S D n / Gru vsjö scha ktet N yt t sc ha kt Granite drill cores

nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 10 Zinkgruvan mine Distance from ESS Lund 360 km Depth 1200 m Access tunnel 15 km Ore hoist shaft 7m/s 20 tons Personnel hoist shaft 2 km long tunnel planned for new ore volume – 3 Memphys cavities could be built adjacent to this tunnel. Extension of access tunnel and second hoist shaft needed. New ore volume

Currently we are investigating the possibilities offered by the North shaft and decline of the Garpenberg mine In tons (= m 3 ) of ore was transported with trucks on the decline up to the shaft hoist at 830 m depth and hoisted up to the ground level so m 3 can be hoised in 7 years. The hoist and shaft will no longer be used for mining after 2014 and can therefore be use for the detector cavern excavation. Bore holes have been made out to the granite zone and recent rock strength measurements of 18 granite bore core samples collected have yielded a mean value of the uniaxial compressive strength of 206 MPa (cf. 232 Mpa at Pyhäsalmi mine). The rock stress magnitude at 880 m depth has been measured and is about 40 MPa (cf. 52 MPa at Pyhäsalmi mine at 900 m) nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 11

In Pyhäslami there is mafic or intermediate volcanics, in Garpenberg early granites and in Kamiokande amphibolite and gneiss. They all represent volcanic, non- sedimental rock which is the most competent rock for making large excavations. The proposed location at Gapenebrg Norra is good regarding the geological aspects. The area is dominated of forests on surface. There are only 6 different owners of the land including Boliden AB, Hedemora Kommun and Sveaskog owned by the Swedish state. There are a few houses located about 1 km from the proposed area nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 12 Granite drill cores

For construction of the neutrino detector there must be an approval from the environmental court, Miljödomstolen, about the outlet of water, management of rock from the excavation, noise level and other environmental aspects. The most critical factor is the disposal of the large amounts of waste rock. However, as the rock outside the mine syncline does not contain sulfur and other contaminating elements like the rock inside does, it should be possible to sell it as construction material nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 13

The saving in cost by using Bolidens mining infrastructure is of the order of 100 MEUR and the gain in construction time ca 5 years. There is an urgent need for negotiations with Boliden and establish a “Letter of Intent” type agreement to keep the Garbenberg Norra infrastructure in operational order until can be taken over by ESSnuSB. LIST OF USEFUL EQUIPMENT AND INFRASTRUCTURE IN GARPENBERG NORRA - Complete hoist installation down to 850 m including spare parts for the hoisting of rock - Complete coarse crusher on level 800 with feeders and conveyer belts - Complete skip-loading station on level Headframe with pockets for hoisted rock. - Decline tunnel down to 1200 m used for transport by trucks - Electrical installations for power supply of the equipment - Pumping and ventilation installations nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 14

The detector cavern site will be accessed from the bottom of the hoist shaft through a ca 1km long horizontal tunnel and from there be excavated downwards. The walls of the cavern must be secured against spalling by inserting a large amount of bolts of several meters length in the walls and by covering the walls with a meter-thick lining of concrete (“shotcrete”). There are different ways of containing the water, the simples being to cover the concrete lining with a water- tight plastic membrane nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 15 Infrastructure needed for the water Cherenkov neutrino detector MEMPHYS cavern wall reinforcement bolts

The water in the cavern which needs to be continuously filtered and purified in an industrial size purification plant and temperature monitored. There must be ventilation, access tunnels and control rooms The order photo-detectors need to be mounted on large frames that maintained the detectors in position with good precision. High voltage and signal cables must be laid out and connected. There must be water transparency and photo-detector efficiency monitors of several different kinds nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 16 Super-Kamiokand e

nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 17 Coarse ESSnuSB cost estimate Unit: Billion Euro (10 9 Euro) Upgrading the ESS accelerator0.1 Accumulator ring0.2 (* Target station0.2 Photodetectors0.2 Detector cavern construction and infrastructure ESS neutrino Super beam project 1.2 (* this cost to possibly be shared with the neutron physics community

Three major studies of future Megaton water Cherenkov detectors have been made over last few years nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 18

nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 19 arXiv: Jan 2013

nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 20 arXiv: Apr 2012

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There is currently an intense development of new photo- detectors nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 22

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nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 25 Micro Channel Plate - Photo MultiplierTubes

nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 26 Large Area Picosecond Photo Detectors

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Far Detector and Underground Site Work Packages and Tasks for the EU/Horizon 2020 ESSnuSB Design Study 1. Underground site 1.1 Site location and access 1.2 Cavern shape, excavation and reinforcement 1.3 Cavern services infrastructures and safety 1.4 Relation to the concurrent Boliden mining activity 2. Far Detector 2.1 Photo-detectors with cables, high voltage and read-out electronics 2.2 Water supply and purification 2.3 Detectors and water quality monitoring 2.3 Data acquisition and computing 2.3 Simulation and reconstruction of signal and background, nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 31

Conclusions The far detector needs to be a Megaton water Cherenkov detector to attain a sufficiently large detector volume The far detector needs to be located about 1000 m underground in order to enable measurements of proton life-time and supernova neutrinos There are suitable mining infrastructures in stable rock available around the location of the second oscillation maximum –the Garpenberg mine is our prime candidate ee 2nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 32

It is important to soon write a Letter of Intent with the owner Boliden of the Garpenberg mine in order to be able to use for the detector caver construction the Garpenberg Norra mining infrastructure that Boliden will soon abandon The detector cavern and its infrastructure represent a dominant cost in the ESSnuSB budget Extensive reports on three different future Megaton water Cherenkov detector projects have been written over the last few years which we should study and make maximum use of for ESSnuSB There is an currently an intense and promising development of new photon detectors which should be we should explore and exploit nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 33

nd ESSnuSB Meeting in Lund Tord Ekelöf Uppsala University 34 Thank you for your attention Garpenberg Castle