Beamline for the LBNE Project Heidi Schellman for

Beamline for the LBNE Project Heidi Schellman for the LBNE collaboration

LBNE Experiment Baseline = 800 miles Near Detector 20 miles underground LBNE @ ICHEP http: //www. bnl. gov/newsroom/news. php? a=23745 2

Goals: Mass Hierarchy and CP violation • A ~ pure νμ beam generated by the ~120 Ge. V MI proton beam. • Wide-band matched to the L/E for the first and second oscillation maxima for a 1300 km oscillation length. NH ≈ 780 νe events ≈ 7000 νμ events Measure relative νμ and νe rates at Far Detector for neutrinos and anti-neutrinos LBNE @ ICHEP 3

MH and CP Sensitivities Top of band: Best case beam and interaction systematics (with near detector) Bottom of band: Worst case beam and interaction systematics (no near detector) Exposure: 34 kt x 1. 2 MW x 6 years (half ν + anti-ν). LBNE @ ICHEP 4

Beam Extract from Main Injector at 60 -120 Ge. V 5. 8 degrees down Plan for 1. 2 MW beam power at start Upgrade path to 2. 3 MW NUMI-like Go up first! ~1 m graphite target 2 Focusing horns 204 m Decay pipe 5. 8 degrees down Physics report LBNEar. Xiv: 1307. 7335 LBNE @ ICHEP 5

Design challenges • • Maximize beam power at the right energies Cost optimization Radiological safety System reliability – – – Corrosion Cooling Radiation damage Accessibility Spares LBNE @ ICHEP 6

Neutrino flux uncertainties • Need to understand the beam parameters very well as physics results depend on ability to estimate the neutrino flux – Avoid multiple interactions in the target – Alignment tolerances – Spot size – Downstream material – Horn behavior • Near detector helps a lot as much of this cancels in a near/far ratio LBNE @ ICHEP 7

New since 2012 Conceptual Design • Be ready for 1. 2 MW on day one (previous talk by Steve Brice) • Helium instead of air in the decay pipe to increase the neutrino flux and reduce the systematics • Optimization studies for beam energy 60 -120 Ge. V LBNE @ ICHEP 8

Target Hall/Decay Pipe Layout Decay Pipe concrete shielding (5. 5 m) Work Cell helium-filled Baffle/Target Carrier steel anels Cooling p Target Chase: 1. 6 m/1. 4 m wide, 24. 3 m long LBNE @ ICHEP 204 m 4 m Geomembrane barrier system to keep groundwater out of decay region, target chase and absorber hall 9

Preliminary target design for 1. 2 MW Currently simulating this target design and the Nu. MI horns with MARS and GEANT. Graphite fin stress mm 47 graphite segments, each 2 cm long Water line stress LBNE @ ICHEP 10

Preliminary target design for 1. 2 MW • Expect to change a graphite target ~2 -3 times a year during 1. 2 MW operation – Limited lifetime due to radiation damage to graphite and thermal stresses – Increase the beam rms of 1. 7 mm and Increase the graphite fin size to 10 mm • Considering as an alternative a Be target – Radiation damage a factor of 10 less than graphite (subject of R&D) LBNE @ ICHEP 11

Horn Operation at 1. 2 MW Water Tank Parameters 700 k. W 1. 2 MW Current Pulse Width 2. 1 ms 0. 8 ms Cycle Time 1. 33 s 1. 20 s Horn Current 230 k. A Target Width 7. 4 mm 10 mm Protons Per Spill 4. 9 X 1013 7. 5 X 1013 • Beam heating and joule heating on horn 1 generate unacceptable power input into the horn inner conductor with the new target design and the Nu. MI horn power supply (2. 1 ms pulse width). • Higher energy depositions from the target can be offset by reducing the current pulse width to 0. 8 ms (requires a new horn power supply). • These changes allow the design current to remain at 230 k. A which is the upper current limit for a Nu. MI conductor design. LBNE @ ICHEP 12

Decay pipe § Concentric Decay Pipe. Both pipes are ½” thick carbon steel § Decay pipe cooling air supply flows in four, 28 -inch diam. pipes and the annular gap is the return path (purple flow path) (Helium increases the n flux by ~10%) LBNE @ ICHEP 13

LBNE Absorber Complex – Longitudinal Section The Absorber is designed for 2. 3 MW A specially designed pile of aluminum, steel and concrete blocks, some of them water cooled which must contain the energy of the particles that exit the Decay Pipe. Thermal, structural, mechanical engineering development in progress Decay Pipe CCSS Steel Al Steel concrete Hadron Monitor (needs R&D) LBNE @ ICHEP 14

LBNE Near Detector Dr. Zelimir DJURCIC at 1630 today in the Neutrino section • Fine-Grained Tracker – 460 m from target • Low-mass straw-tube tracker with pressurized gaseous argon target • Relative/absolute flux measurements • High precision neutrino interaction studies ≈ 107 interactions/year! • Additional target materials possible • Proposal pending in India LBNE @ ICHEP 15

Physics optimization studies • Use G 4 LBNE – GEANT 4 simulation based on G 4 NUMI • LBNE Fast MC for detector efficiency/purity – GENIE event simulation – Parameterized detector response Target LBNE @ ICHEP Horns 16

Beamline contributions to absolute flux Predicted absolute flux errors at the near detector vs. energy LBNE @ ICHEP 17

Errors on Near/Far ratio LBNE @ ICHEP 18

Mostly cancel in a near/far ratio 0. 5 mm alignment tolerances lead to error on Near/Far ratios << statistics Near to far ratio is less sensitive LBNE @ ICHEP 19

Signal rates at different proton energies Estimated ne rates for baseline 3 yrs @ 1. 2 MW beam power, 35 k. T detector Events/ Ge. V Feed-down source Signal region Integrated difference in figure of merit S/√S+B between 120 and 80 Ge. V is +8% for n, +16% for ν LBNE @ ICHEP 20

Helium vs. Air Study for neutrino beam mode – LBNE doc: 8144 He yields 11% more flux 1. 5 -5 Ge. V 4% less anti-nu background 1. 5 -5 Ge. V LBNE @ ICHEP 21

Potential optimizations Ratio of nm ne CC appearance rates at the far detector Change 0. 5 -2. 0 Ge. V 2. 0 -5. 0 Ge. V DK pipe Air He * 1. 07 1. 11 DK pipe length 200 m 250 m (4 m D) 1. 04 1. 12 $ DK pipe diameter 4 m 6 m (200 m L) 1. 06 1. 02 $ Horn current 200 k. A 230 k. A 1. 00 1. 12 Proton beam energy 120 ->80 Ge. V 1. 14 1. 05 Target graphite fins Be fins 1. 03 1. 02 ~1. 4 ~ 1. 5 Subject of R&D Total Comment Increase target lifetime • Simplifies the handling of systematics as well • Recently approved LBNE @ ICHEP 22

Timeline From the P 5 report LBNE @ ICHEP 23

Conclusions • Significant progress with preliminary design effort in many Beamline systems. • Robust simulation framework is aiding physics and value optimization • Lots of opportunities for collaboration on Beamline components as well as on beam simulations and R&D efforts. LBNE @ ICHEP 24

Design Opportunities Beam simulations Primary beam magnet and power supply design and construction Primary and neutrino beamline instrumentation Target R&D Target, Baffle and Horn support modules Horn R&D for 2 nd generation horns @ 1. 2 and 2. 3 MW Design and construction of cooling panels for the target chase shield pile Upstream decay pipe window Corrosion studies for target chase, decay pipe and absorber Radiation simulation verification – simulate known irradiations at known facilities and compare with actual measurements • Hadron production studies that provide essential input for the prediction of the neutrino flux. • And many more…. . • • • LBNE @ ICHEP 25

BACKUP LBNE @ ICHEP 26

Beam design parameters The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe ar. Xiv: 1307. 7335 LBNE @ ICHEP 27

Parameters cont. LBNE @ ICHEP 28

Proton Improvement Plan-II Performance Goals PIP-II doc: 1232 S. Holmes et al. - 80 Ge. V LBNE @ ICHEP 29

Proton-Improvement-Plan Phase II (PIP-II) • Replace existing 400 Me. V linac with a new 800 Me. V superconducting Linac • 1. 2 MW beam power to LBNE at start-up of experiment. • Plan is based on well-developed superconducting RF technology. • Strong support from DOE and in the recent Prioritization Panel report. • Flexible design - future upgrades could provide > 2 MW to LBNE. Steve Brice Talk LBNE @ ICHEP 30

R&D needs • At 1. 2 MW R&D will be needed on: – target (materials) • assuming minimal modifications will work – horns (2 nd generation) • assuming minimal modifications will work – hadron monitor • At 2. 3 MW additional R&D will be needed on: – – target (materials, shape, cooling, …) horns hadron monitor primary beam window (only cooling aspects affected by 1. 2 MW) LBNE @ ICHEP 31