Neutron Instrumentation Carla Andreani Universita’ degli Studi di Roma Tor Vergata-Dip. Fisica e Centro NAST
SoNS September 2010 SYLLABUS SCATTERING EXPERIMENT TIME OF FLIGTH TECHNIQUE THE SPACE INSTRUMENT IN DIRECT GEOMETRY EXPERIMENT IN DIRECT GEOMETRY INSTRUMENT IN INDIRECT GEOMETRY EXPERIMENT IN INDIRECT GEOMETRY
After moderation SoNS September 2010
MILANO MARZO 2005 SoNS September 2010
Geometria diretta
Theorists have predicted a new excitation The bound pairs of spins propagate away – these are Spinons Normal anti-ferromagnet Flip one spin Normal spin wave Spinon continuum MAPS The signature of this excitation was seen using inelastic neutron scattering Quantum Magnetism
Making MAPS of Magnetism Pixel Power USA Japan
Geometriainversa
Lo spettrometro ad asse triplo ad asse triplo
Triple Axis Spectrometer
“old” HB3, HFIR “new” HB1, HFIR
& PRISMA
VESUVIO&e.VERDI: A RFS and RDS spectrometer RDS at very small scattering angles (1°< 2 < 5°) RFS at forward and backscattering angles Filter changer n
Come selezionare i neutroni in energia nell’intervallo eV ? Analizzatori meccanici (“Choppers”): –I neutroni sono troppo veloci Cristalli analizzatori –I neutroni hanno troppo corte Allora… Risonanze nucleari –Due possibili configurazioni sperimentali
VESUVIO-Spettrometro a geometria inversa campione moderatore L0L0 selettore di velocità contatore di neutroni acquisizione L1L1
Spettrometri a geometria inversa DAE analizzatore campionemoderatore 22 L0L0 L1L1 Spettri temporali rivelatore
Double Difference (DD) When (E) is small Lorentzian wings are removed 1-e -Nt ≈ Nt as 0 Resolution reduction of ~2 for U and Au foils
The Resonance Filter Spectrometer sample filter Li-glass detector n’ n DAE stop start target p bunch TOF spectra PMTPMT electronic chain
The Resonance Detector Spectrometer X sample Analyser foil (n, ) reactions detector n’ n DAE stop start target p bunch TOF spectra Fast electronic chain