LArTPC R&D status. 2015/Aug./5, Workshop for Neutrino Programs with facilities in Japan Ken Sakashita (KEK/J-PARC)

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1 LArTPC R&D status 215/Aug./5, Workshop for Neutrino Programs with facilities in Japan Ken Sakashita (KEK/JPARC) R&D collaboration with Iwate University, Yokohama National University and Kure National College of Technology 1. Introduction 2. Status of LArTPC R&D at KEK 3. Outlook & Summary

2 Introduction Liquid argon TPC (LArTPC) has a capability of good particle identification and good energy resolution up to several GeV A large size LArTPC(>1kton) is a candidate of neutrino detector for longbaseline neutrino oscillation physics studies (CPV,MH), nucleon decay search, SN neutrino observation, atmospheric neutrino measurements etc. Largest LArTPC up to now is ICARUS T6 (3ton x 2) c.f. DUNE 1kton detector = 58m x 14m x 12m (plan) Establishing key technologies to realize a large LArTPC detector with affordable cost is an urgent subject

3 R&D activity at KEK We aim for realization of a long drift toward a large scale LAr detector event containment reduce # of readout channel (cost down) We focus necessary fundamental technologies R&D toward a realization of the long drift using small scale LArTPC detectors (1L, 25L detectors) High purity High voltage Readout system Today s talk : stable long term operation with purity <.1ppb small attenuation by increasing drift velocity (> 5V/cm) low noise & high signal gain readout (S/N ratio > 1) R&D on readout system A new small scale LArTPC detector

4 R&D on readout system Developing an economical and low noise readout electronics Placing the electronics as close as possible to the anode to reduce the detector capacitance small noise Possible improvements C cable : 2~3pF

5 Based on multilayer PCB technologies Making up 4mm pitch strip readout with connecting readout electronics R&D on 2D anode readout board (strip readout) connect to vessel.8mm2 pad signal shape is identical for both x and y channel.,(%(%9"&'(>'bq',&$#(1%':49';<; charge is shared in x and y channel halfandhalf G^"2)'C())&C%(,' anode 3mm 2mm Commercially available largest product is 5cm 28mm x 5cm realize a large area with connecting GG7\' several C5' 28mm ^7VC5' `II15'"$#3' BII15'3"$C& G' B' A' V' boards cg' cb' ca' cv' ^7VC5' /G' /B' /A' /V' 21mm G^"2)'C())&C%(,' 76cm x 4cm anode H23'%&CH)(D(N9'23'("&)& LAr :8$)(41'$)$O$S'7!CH2# GBC5' cathode QG' QB' QA' QV' To connector 4mm To connector 4mm 4cm 38cm signal size is 1fC/mm * 4mm * 1/2 (single phase readout) 4mm pitch readout. 38ch in total G' B' A' V' cg' cb' ca' cv' /G' /B' /A' /V' <DPFF QG' QB' QA' QV' <DSFF <DSFF I7`55'"$#3'.8mm I7B55'3"$C& pad (developed with KEK esys group).2mm space

6 Cosmic ray events w/ a large area anode board 76cm x 4cm readout test : cosmic ray events [w/ CAEN TPC readout elec.] xz view Event#1 yz view 4cm 76cm 4cm (drift length) 25L detector xz view Event#2 yz view Toward larger area readout, we aim to reduce the capacitance of the anode board

7 Development of economical and lownoise electronics We re developing a frontend chip (ASIC) for a low noise analogue preamplifier LTARS ASIC (1st version) 8ch preamp. & shapers in a chip (2.8mm x 2.8mm) acceptable det. capacitance ~1pF operation voltage ±2.5V aiming to use in the low temperature environment (in first, testing in warm temp.) LTARS ASIC chip ref: Yuya Iwazaki s Master thesis, Yokohama National U. (214) developed with KEK esys group, one of Openit projects

8 Performance evaluation inputs (from LAr) Output voltage [mv] 25 9cm Equivalent Noise Charge [electrons] ASIC chip 12cm outputs (to ADC) 12 ENC ~11 2 Gain(*) ~3mV/fC Input charge [fc] 7 8 (*) ~1% decrease of gain@cd=1pf 1 8 Performance is consistent with the ASIC design (expectation from simulation studies) Detector Capacitance [pf] 1 all the measurement done by Y.Iwazaki (Yokohama National University)

9 Performance check w/ cosmic events using a small det. ( 1L ) Pulse hight [ADC] Drift time [T μsec] Drift time [T μsec] x position [mm] Pulse hight [ADC] Drift time [T μsec] Drift time [T μsec] S/N > 1 (single phase readout) D anode y position [mm] cosmic μ Trigger Scint. Trigger Scint. MIP signal ~12ADC in ch4 (noise ~11ADC in RMS) Signal size was evaluated from ~6 cosmic muon tracks # of events signal size, noise size are as expected Intensity 2D anode field shapers cathode 6.4cm (anode area) temp. Hit ADC anode grid 5.5 cm

10 Development of next version ASIC Toward a large size detector readout, we develop a next version of ASIC LTARS214 ASIC LTARS214 ASIC chip (5mm x 5mm) specification change from the previous version 32ch in chip (# of ch. per chip is increased) acceptable det. capacitance ~3pF operation voltage ±.9V low power consumption (< 5mW/32ch) expected noise is ~2 conv. gain ~9mV/fC Performance of the ASIC is under evaluation study by Y.Kuromori (Iwate University) L.Zambelli (KEK) developed with KEK esys group, one of Openit projects

11 A new small detector Preparing a new small detector which is used for fundamental tech. R&D Design based on the knowledge accumulated so far Improving some issues in the previous small detector e.g. nonuniform electric field Electric field simulation study was performed Commissioning is planed by the end of this month 3L detector

12 Electric field study using a FEM tool We studied the electric field in the TPC field shaper using a FEM tool (COMSOL4.4)!"'1!( Configuration: MN4 %)?N@!I5% =.!4@ 477 )*,% 45 =.@!%%%%%@!I5% AGCathode electric potential (at x=, each z position) MN4 %)?N@4:8#I5%!"'1!( MN4 %)?N@!I5% MN4 %)?N@4:8#I5% MNG# %)?N@!I5% MNG#:! %)?N@4:8#I5% =.@;%%@G:3I5 =.@!4%%@3:3I5 'C&%12B6D*%% %%%%%%%%%%%%%%%%%%%%%%%45 MNG# %)?N@!I5% MNG#:! Uniform %)?N@4:8#I5% electric field (5V/cm) is formed in the fiducial volute ( x,y < 32mm ) 477 mm ;477 6mm study by Y.Kuromori (Iwate University)

13 Improvement of nonuniform electric field old anode board: $%&'() PL Configuration: )*, old anode board: 9 9 % )*,!84779!84779!:;77% ;<779;<7794:877% % % =>< niformity of Electric Fie new anode board: % )*,!84779!84779!:;77%!44779!447794:877% ;<:#779;<:#7794:877% ;<779;<7794:877% % % =>< 1LTPC Line of Eforce 2cm 4 new $%&'() PL anode board: Anode 6cm Cathode 1cm 2cm Anode Grid Shaper 4 1cm In the old configuration, anode readout area is 64mm x 64mm while the inner surface of TPC field shaper is 1mm x 1mm. This difference causes nonuniform Efield around the edge of anode. This nonuniformity is improved by adding an electrode around the readout area.

14 Outlook & Summary We focus fundamental tech. R&D using small scale detectors at KEK We re developing preamplifier ASIC as an economical & lownoise readout electronics A new small scale detector is prepared we will perform fundamental tech. R&D, such as 2D strip anode board, readout electronics, high voltage generation, LAr purification etc. using this detector ( experimental proof will be performed using a larger detector such as the 25L detector) We re also studying at CERN neutrino platform (WA15 experiment) for R&D on a large scale prototype detector