Developing LAr Scintillation Light Applications at Neutrino Energies with LArIAT Andrzej Szelc, Manchester (for the LArIAT collaboration)
What is LArIAT? A test facility to calibrate and test LArTPCs and their components using a beam of charged particles and a test-beam experiment. Reusing the ArgoNeuT detector with small modifications: ● front flange modified with excluder + Titanium window. ● Side flange modified to allow for Light System. ● Bottom flange modified to enable liquid recirculation (quicker purification). More details in Run 1 completed. Ernesto Kemp's Run 2 completed. Talk Run 3 completed. 24/09/17 A. M. Szelc @ FAPESP DUNE workshop 2
Light Collection System ● Available photocathodic coverage (and therefore choice of PMTs) limited by size of side flange. ● In a way a similar problem to future large scale detectors. 24/09/17 A. M. Szelc @ LIDINE 2017 3
Solution – recover light falling on walls Applying TPB to the reflective foil that will line the inside of the LArIAT TPC Wavelength shifting reflector LArTPC foil First test of TPB ● coated reflector foils in a running TPC (at beam neutrino energies). Run I & II, Copper Cathode. Run III, mesh cathode with WLS foils installed. 24/09/17 A. M. Szelc @ LIDINE 2017 4
Foils ● LArIAT used VIKUITY ESR foils. Possible to use DF2000MA. ● Excellent reflectivity in visible wavelengths. ● Evaporation using LTE Evaporator (300 ug/cm^2 thickness). ● Stable operation for 3 subsequent runs (3 years) Measurements by B. Littlejohn, IIT, PROSPECT 24/09/17 A. M. Szelc @ LIDINE 2017 5
Light Collection Uniformity U s i n g L A r S o f t S i m u l a t i o n t o o l s d e v e l o p e d t o a c c o u n t f o r o p t i c a l f o i l s ( c h e c k e d b y s t a n d a l o n e c o d e ) t o m o d e l d e t e c t o r r e s p o n s e . T o p - d o w n v i e w T o p - d o w n v i e w L A r I A T L A r I A T P h o t o n M C P h o t o n M C L Y = 1 4 . 1 p e / M e V L Y = 6 . 2 p e / M e V Good uniformity in the detector. S i d e v i e w S i d e v i e w Enables new uses of scintillation light. Beam Direction W. Foreman Beam Direction 24/09/17 A. M. Szelc @ LIDINE 2017 6
Validating the Simulation μ + / - ● Simplest topology – easy to understand. ● Calculate energy from L A r I A T P r e l i m i n a r y T h r o u g h - g o i n g μ range or dE/dx E T L ( 2 ” ) P M T deposition. ● Compare with Light collected by PMTs. ● More complex P . K r y c z y n s k i topologies and protons (in progress). 24/09/17 A. M. Szelc @ LIDINE 2017 7
Energy Calibration with Michels M. Sorel JINST 9 (2014) P10002 ● M i c h e l - c a n d i d a t e s i g n a l s i n t e g r a t e d t o g e t P E s p e c t r u m M M C P r e d i c t i o n M C P r e d i c t i o n C r e p r o d u c e s s h a p e w e l l . G i v e s m o r e c o n fj d e n c e i n s i m u l a t i o n m o d e l . L Y c o m p a t i b l e w i t h t h r o u g h - μ e n d p o i n t w i t h i n 1 5 c m o f T P C c e n t e r g o i n g m u o n s a m p l e . U n i f o r m i t y g r e a t l y h e l p s End goal: combine charge + light to get full energy reconstruction. W. Foreman 24/09/17 A. M. Szelc @ LIDINE 2017 8
Closing the loop: foils on the cathode A way of putting foils on cathode without affecting electric field is to sandwich them in a mesh. A small mesh-cathode (SBND-like). was installed in LArIAT beginning of march. 24/09/17 A. M. Szelc @ LIDINE 2017 9
Mesh Cathode Runs We performed two dedicated subruns with an SBND like cathode (with and without foils installed). No problems in TPC BEFORE operation observed. Final results in preparation. AFTER 24/09/17 SBND Collaboration Meeting, Sep. 2017 10
Delayed light in liquid argon ● Space charge effects in LArTPCs on the surface could manifest as delayed scintillation light from recombining positive ions (see R. Santorelli talk) . ● The positive ion drift velocity ~0.8 cm/s (@500V) leads to time scales much longer than typical LArTPC readout frames ( o(10s) vs o(ms) ). ● Impossible to correlate this light with single events. Should instead manifest as extra “light noise”. 24/09/17 A. M. Szelc @ LIDINE 2017 11
LArIAT Beam Structure 4 sec 26 sec Charge injected into the system Time for positive ions to drift from anode to cathode at 500V Pulser Run Readout 56 sec LArIAT has the benefit of a 4 – second beam spill ● every 60 seconds. Coincidentally drift from anode to cathode at 0.8 cm/s is ~60 seconds. LArIAT should be able to tell us something if the ion ● light is there. 24/09/17 A. M. Szelc @ LIDINE 2017 12
Dedicated pulser runs ● Several sets of dedicated pulser runs taken. ● Random trigger, 28 us Waveforms. ● Looking for random light noise PMT calibration performed in-situ on tails of LAr scintillation events. Single phel counting to obtain number of random phel. 24/09/17 A. M. Szelc @ LIDINE 2017 13
Preliminary Results ● Varying beam intensity and E-Field (0 – 600V/cm) PRELIMINARY ● “Cosmic only” runs taken at same voltages. ● We observe an effect of the beam spill. ● Analysis in progress – have runs in different PRELIMINARY configurations, should be able to say some things about location. BEAM WINDOW 24/09/17 A. M. Szelc @ LIDINE 2017 14
Large foil production ● We now have infrastructure needed to manufacture large evaporated surfaces (up to 60x60 cm 2 ) at Manchester. ● Planned to be used for SBND production, but we're interested in new projects. D. Garcia-Gamez and F. Spagliardi with first LArIAT cathode foil. 24/09/17 A. M. Szelc @ LIDINE 2017 15
Summary ● LArIAT light collection system is a new approach (at these energies). ● Smaller photocathodic coverage can be compensated with WLS-covered foils. ● Enhanced uniformity enables calorimetric studies and muon sign discrimination. ● LArIAT analyses on using light and combined light + charge for calorimetry, particle ID are in progress. ● Lessons learned instrumental in preparing proposal to install foils on SBND CPA. 24/09/17 A. M. Szelc @ LIDINE 2017 16
Thank You for your Attention 24/09/17 A. M. Szelc @ LIDINE 2017 17
Fermilab Testbeam Facility Fermilab Testbeam Facility The LArIAT testbeam experiment is running in MCenter – allows long term occupation (as opposed to MTest). Main Injector One 4s long spill per minute Secondary beam max 300k particles/spill MTest Main injector protons MCenter Secondary 24/09/17 A. M. Szelc @ LIDINE 2017 18
LArIAT Beamline Tertiary Beam We will use a Tertiary beam (Similar to at MCenter MINERvA beam test). We want to study charged particles in the energy range relevant for future neutrino experiments . We can tune their energy by adjusting the parameters of the beamline, Tertiary Beam composition Particles from ν interactions NuMI LE on-axis 24/09/17 A. M. Szelc @ LIDINE 2017 19
LArIAT Beamline Optimized to study charged particles in the energy range relevant for future neutrino experiments . We can tune their energy by adjusting the parameters of the beamline, Particles from ν interactions Tertiary Beam composition NuMI LE on-axis 24/09/17 A. M. Szelc @ LIDINE 2017 20
Beamline Elements Magnets + TOFs + MWPC ● MWPCs allow reconstructing momentum and PID of particles in the tertiary beam. ● TOFs Controlled sample of particles hitting the TPC. 24/09/17 A. M. Szelc @ LIDINE 2017 21
m vs p separation in beamline 24/09/17 A. M. Szelc @ LIDINE 2017 22
Example Waveforms PMT calibration performed in-situ on tails of LAr scintillation events. Single phel counting to obtain full light spectrum. 24/09/17 A. M. Szelc @ LIDINE 2017 23
Triggers ● Can use combination of triggers. – LARSCINT – trigger on amplified ETL signal (-12 mV) – MICHEL – catch Michel 1 1 6 H z a t 1 2 m V electrons/positrons (=next slides) t h r e s h – SCINTGATE (400 us gate after each LARSCINT) – LARRY: muon “telescope” U p p e r c o s m i c ● Coincidence of LARSCINT μ p a d d l e μ with either of upper cosmic μ paddles. ● Catches both through going and stopping muons. T P C 24/09/17 A. M. Szelc @ LIDINE 2017 24
Muon absorption on argon m - have a predicted 75% capture rate on argon nuclei (no Michel electron present). D a t a s e t : ~ 1 2 d a y s M. Sorel JINST 9 (2014) P10002 L I D I N E 2 0 1 5 P r o c e e d i n g s , J I N S T Neutrino vs. anti-neutrino 1 1 C Statistical discrimination 0 1 0 3 possible, e.g. in the DUNE 7 far detector W. Foreman
Time Projection Chamber 24/09/17 A. M. Szelc @ LIDINE 2017 26
Recommend
More recommend
