Commissioning of new DC muon beam line, MuSIC- RCNP at Osaka University Dai Tomono Research Center for Nuclear Physics (RCNP), Osaka University On behalf of the MuSIC- RCNP collaboration tomono@rcnp.osaka- u.ac.jp PSI2016, 19th Oct. 2016 MuSIC- RCNP b y Dai Tomono@PSI2016 19/Oct/2016 1
Outline 1. MuSIC beamline 2. Beam commissioning (yield and spin measurement) 3. MuSIC status 4. Summary Me MuSIC- RCNP Collaboration (Jun, 2016) MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 2
MuSIC beamline at RCNP, Osaka University MuSIC (Muon Science Innovative muon beam Channel) beamline? l pion capture solenoid + pion collection solenoid + conventional triplet- Q & bends beamline l world s most efficient DC muon beam source ( ~ 10 3 ) p Pion capture solenoid Triplet- Q + Bending magnets e, µ, p, Curved solenoid 36 Large pion/muon collection efficiency ~ 10 3 Beam transport l Present status 10 8 muons are obtained at the curved solenoid end construction of whole beamline is almost completed beam commissioning with 20nA proton beam prepare experimental port and apparatus MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 3
MuSIC Beamline MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 4
Research Center for Nuclear Physics (RCNP), Osaka University MUSE @ J- PARC Pulsed muon source MuSIC @ RCNP, Osaka Univ. DC muon source Ring Cyclotron ~392MeV (variable) 1uA proton, (0.4kW) p MuSIC M1 beamline - only 100 MeV above pion production threshold ( ~ 2m p ) - muon source with low proton power (1uA 0.4kW, 5 ua in future) MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 5
Layout of Music M1 Beamline Experimental port Triplet- Q µ/e/p Spin rotator & DC separator Triplet- Q BM2 Pion capture solenoid ST1 ST2 BM1 Triplet- Q +/- 400 kv / 15cm gap L = 1.8 m muon / electron separation rotate spin with 80 degree for surface muon Now in commissioning p MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 6
Comparison of pion production methods Conventional muon beamline MuSIC beamline proton beam graphite target Ex. J- Parc MUSE 1000 kw proton beam 20mmt graphite target capture magnet bend (p selection) Transport solenoid muon pion proton beam Ex. MuSIC 0.4 kw proton beam 200 mmt graphite target Proton beam loss ~ 5% pion decay volume Capture solenoid bend (µ selection) Collect p / µ with 3.5T solenoidal field to neutron facility muon to dump Thin target (~ 20mmt) Small solid angle Separate pion and muon momentum selection (obtain highly polarized muon beam) Thick target ( 200mmt ) Large solid angle, good collection efficiency No muon spin selection ( no selection of pion / muon momentum ) MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 7
Pion capture solenoid & Pion transport solenoid l Pion capture solenoid (3.5T) pion production target inside (1.5 interaction length) pion collection with large solid angles l Pion transport solenoid (2.0T) Curved solenoid to capture and transport pion/muon Momentum selection with dipole collection field Beam Profile by G4beamline simulation Surface muon Inflight- decay muon exit of the 36 curved solenoid ~ 3x10 8 positive muons ~ 1x10 8 negative muons ~ 10 3 pion production efficiency MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 8
Beamline Commissioning MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 9
Experimental port (at the beamline end) Muonic X- ray measurement µsr spectrometer Beamline end TOF setup Muon beam Now commissioning is in progress MuSIC- RCNP b y Dai Tomono@PSI2016 19/Oct/2016 10
Muon yield measurement Inflight- decay muons (μ ± ) Surface muon (µ + ) Muon intensity [muon/sec/ua proton] 140 120 100 80 60 40 20 Negative muon 3 10 ~1x10 5 μ /s @60MeV/c with 1μA proton beam 0 10 20 30 40 50 60 70 80 90 100 muon momentum [MeV/c] Muon momentum [MeV/c] Muon intensity [muon/sec/ua proton] 3 10 1000 900 800 700 600 500 400 300 200 100 Positive muon ~7x10 5 μ+/s @60MeV/c with 1μA proton beam 0 0 10 20 30 40 50 60 70 80 90 100 muon momentum [MeV/c] Muon momentum [MeV/c] ** note that muon yield (vertical axis) is scaled for 1uA proton beam operation 20nA (2016 run) - > 1uA (2017 run) TOF Setup Muon intensity [muon/sec/ua proton] beamline ~ 20m Succeed in observing surface muons (~28 MeV/c) Target position tuned for surface muon ~ 3 x 10 4 surface µ+/s @ 28 MeV/c with 1 ma proton beam Inflight- decay muons Muon momentum [MeV/c] Beam counter (plastic scintillator) (10cmx 10cm) e/µ/p D t = t counter t RF MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 11
Beam profile measurement Beam profile at the beamline end (beam focusing position) p =28 MeV/c slit fully opened 80 mm x 80 mm 80mm 80mm simulation (turtle) measured slit ±30mm opened 50 mm x 50 mm X Y Profile monitor 160mm 160mm 50mm 1mmφ thin scintillation fiber + MPPC readout Separate e / µ by their energy deposit difference 8mm~2mm interval(dense around the center) 50mm MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 12
Spin measurement Number of muons [count] Preliminary (simulation with G4 beamline ) Surface muon (spin ) FW( spin ) Muon beam at the solenoid end (G4 beamline output) Separate forward and backward decay muons to investigate beam polarization Calculate the expected polarization geometrically and compare the experimental results BW(spin ) Muon momentum @ solenoid exit [MeV/c] Setup µ+ TF = 40 Gauss x Trigger counter (0.5mmt) Al Upstream counters (4mmt) x2 Downstream counters (4mmt) x2 spin asymmetry A "#$ t N ) t αn, t N ) t + αn, t MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 13
Number of decay positron [c 800 Spin precession results Number of decay positron Asymmetry [count] Asymmetry 1800 1600 1400 1200 1000 600 400 200 0 0 1000 2000 3000 4000 5000 6000 7000 8000 time [nsec] Typical observed asymmetry spectra 2200 0.20 2000 1800 0.15 1600 0.10 1400 1200 0.05 0.00 1000 800 0.05 600 0.10 400 200 0.15 0 0 1000 2000 3000 4000 5000 6000 7000 8000 0.20 0 1000 2000 3000 4000 5000 6000 7000 time [nsec] 8000 time [nsec] 0.20 0.15 0.10 0.05 0.00 0.05 0.10 0.15 p = 28 MeV/c p = 60 MeV/c 0.20 0 1000 2000 3000 4000 5000 6000 7000 8000 time [nsec] A cos γ 4 Bt + δ 7 γ 4 Lamor frequency Measured polarization Number of muons [count] Momentum [MeV/c] Polarization (G4 simulation) Polarization (measured) 28 (surface µ) 48 57 40 10 16 50 45 59 60 55 57 Cancel Preliminary (simulation with G4 beamline ) Muon momentum @ solenoid exit [MeV/c] Polarization (spin ) MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 14
Muon Science at MuSIC l Stage 0 proof- of- principle for muon capture and transport solenoid (also for COMET experiment) high efficiency (~ 10 3 ) muon production was achieved ( measured at the capture solenoid end) l Stage 1(2012-16) Conventional triplet- Q and bend magnets were installed successively to the collection solenoid. Beam commissioning is now in progress Physics programs start Muonic X- ray analysis and non- destructive analysis Chemistry on muonic and pionic atoms non- destructive element analysis (ex, from asteroid explorer, Hayabusa- II ) Probes for condensed matter physics (DC- µsr), Feasibility tests are now in progress We are now in this stage (2016) l Next stage and future Muonic X- ray analysis DC- µsr study for users Nuclear physics Nuclear muon capture for 0νββ study (for nuclear matrix element determination, proposed) Gamma- ray measurement from nuclear capture with heavy nuclei Nuclear physics combined with the high resolution / acceptance spectrometer in RCNP (prospects) Improvement of the beamline new physics programs MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 15
First experiment (µ - ) : muonic X- ray & gamma- ray measurement First MuSIC beamline experiment for users (E411) 9 th 11 th Nov., 2015 Fundamental study for non- destructive elemental analysis with muon for analyzing planetary materials brought by Hayabusa2 200 meteorite Count /SEC 100 MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 16 0 70 75 80 Energy (kev) From : K.Terada (Osaka U.) MXG16 slide
Demonstration of fast spin precession with DC muon beam l muon spin precession spectra Asymmetry,A(t) B = 40G(slow precession) 10000 [nsec] B=580G fast precession was observed Setup µ+ Trigger counter (0.5mmt) Upstream counters (4mmt) x2 spin asymmetry TF = 40, 580 Gauss x Test sample (Ag plate) A "#$ t N ) t αn, t N ) t + αn, t 0 Downstream counters (4mmt) x2 MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 T~80 ns (typical magnetic order) Time resolution ~ 1ns 1000[nsec] time[nsec] possibility of DC µsr (proof for high time resolution precession)
Summary l New innovative DC muon source with solenoid system has been developed at RCNP, Osaka University good pion production efficiency of ~ 10 3 pion capture & transport solenoid + triplet- Q and bend magnets beamline l Beamline commissioning is now in progress 28 MeV/c 110 MeV/c muon beam inflight- decay µ + 10 5-10 6 µ - 10 5-10 6 surface µ + 3 x 10 4 [count/sec/1ua proton beam] beam size (<80mmf ), momentum bite (<10%) and polarization (~ 60%) were measured start feasibility study Improvement of muon beam (especially, solenoid and triplet- Q connection) l Physics program in MuSIC nuclear physics ( muon capture ) radio- chemistry and non- destructive evaluation of elements positive muon for µsr measurement (feasibility study to practical physics program) MuSIC beamline will be a highly intense DC muon source. has possibility to perform DC muon source MuSIC- RCNP by Dai Tomono@PSI2016 19/Oct/2016 18