Jacques Bouchez CEA/DAPNIA-Saclay & APC-Paris ISS meeting, detector WG KEK, Jan23 rd, 2006 MEMPHYS : A megaton WČ detector in Fréjus underground laboratory Proton decay Supernovae: explosion, relics Solar and atmospheric neutrinos Oscillations: θ 13 and δ CP using superbeam and betabeam from CERN PHYSICS MOTIVATION

The Frejus site Results of the excavation study The detector Photodetectors R&D Physics performance Schedule most transparencies borrowed from Luigi Mosca (CARE/BENE, CERN, 23/11/05) and from Jean-Eric Campagne (GDR neutrino, Paris, 21/10/05) LAYOUT

The MEMPHYS Project 65m Fréjus CERN 130km 4800mwe Excavation engineering pre-study has been done for 5 shafts Water Cerenkov modules at Fréjus CERN to Fréjus Neutrino Super-beam and Beta-beam

A Very Large Laboratory In the middle of the Fréjus tunnel at a depth of4800 m.w.e a preliminary investigation shows the feasibility to excavate up to five shafts of about 250,000 m 3 each Henderson HK

Main results of the Preliminary Study 1) the best site (rock quality) is found in the middle of the mountain, at a depth of 4800 mwe 2) of the two considered shapes : “tunnel” and “shaft”, the “shaft (= well) shape” is strongly preferred 3) Cylindrical shafts are feasible up to : a diameter  = 65 m and a full height h = 80 m (≈ m 3 ) 4) with “egg shape” or “intermediate shape” the volume of the shafts could be still increased 5) The estimated cost is ≈ 80 M€ X Nb of shafts

Exemple of “egg shape” simulation, constrained by the rock parameter measurements made during the present tunnel and laboratory excavation. The main feasibility criterium is that the significantly perturbated region around the cavity should not exceed a thickness of about 10 m

65m ~ 4 x SK 65m Detector basic unit Detector: cylinder (a la SK) 65 m diameter and 65 m height: : → tons of water (4 times SK) taking out 4 m from outside for veto and fiducial cut → ton fiducial target 3 modules : 440 kilotons (like UNO) BASELINE 4 modules would give 580 kilotons (HK) →Simulations done using 440 kt each cavity 70 m diameter and 80 m total height

PHOTODETECTION Baseline choice: use photomultipliers get the highest possible coverage to get the lowest possible threshold Ideally, we want the same light/MeV as SuperK. …but the solution with 20’’ PMT’s becomes too expensive (cf. UNO) ( ’’ PMT’s/module with 40% coverage) R&D on HPD started in France (with Photonis) encouraging results from ICRR/Hamamatsu with 13’’ HPD

PMT size cost NNN05 Diameter 20“ 12“ projected area cm² QE(typical) % CE % Cost € Cost of useful PE/cm 2 = PM cost /( area x QE x CE) €/PE 40% saving 30% coverage (12’’) gives the same # of PE/MeV as 40% coverage (20’’) the required # of 12’’ PMT’s is twice the # of 20’’ PMT’s BONUS: better timing (risetime+jitter), better pixel localization

R&D on electronics (ASICs) Integrated readout : “digital PM (bits out)” –Charge measurement (12bits) –Time measurement (1ns) –Single photoelectron sensitivity High counting rate capability (target 100 MHz) Large area pixellised PM : “PMm 2 ” –16 low cost PMs –Centralized ASIC for DAQ –Variable gain to have only one HV Multichannel readout –Gain adjustment to compensate non uniformity –Subsequent versions of OPERA_ROC ASICs

ASIC requirements High speed discriminator for autotrigger on single photoelectron Coincidence logics to reduce dark current counting rate (to be defined by MC studies) Digitisation of charge over 12 bits Digitisation of time of arrival over 12 bits to provide nanosecond accuracy Variable gain to equalize photomultipliers response and operate with a common high voltage Data out wireless (why not?) Low cost (aim at 200 euros/channel ) R&D started at LAL Orsay, in connection with Photonis Other interested french labs

Mechanics & PMT tests Basic unit that we want to build and test under water Electronic box water tight IPNO Taken in charge by IPNO: well experienced in photodetectors (last operation: Auger). With PHOTONIS tests of PMT 8”, 9”  12” and Hybrid- PMT and HPD

MEMPHYS physics reach A) non accelerator-based physics Nucleon decay (for 5 Megaton.years) yrs (p→e +  0 ) yrs (p→  K + ) -complementarity with liquid argon -some chance of discovery – Neutrino bursts from Super-Novae explosion –200,000 events from SN at 10kpc –30 events from Andromeda –2 events at 3 Mpc –collapse studies, explosion alerts (grav.antennas, telescopes) –mass hierarchy(θ 13 >10 -3 ), θ 13 sensitivity in [ – ] – Relic Neutrinos from past Super-Novae explosions –100 events in 5 Mt.y (with pure water) –2000/4000 events in 5 Mt.y (with Gd loaded water)

MEMPHYS physics reach B) with CERN super and beta beams ongoing studies within the ISS physics working group

A possible schedule for MEMPHYS at Frejus Year Safety tunnel Excavation Lab cavity Excavation P.S Study detector PM R&DPMT production Det.preparation InstallationOutside lab. Non-acc.physics P-decay, SN Superbeam Construction Superbeam betabeam Beta beam Construction decision for cavity digging decision for SPL construction decision for EURISOL site

CONCLUSIONS The Frejus site can house a large scale (megatonne) detector The preferred geometry is made of cylindrical shafts 3 detectors give an overall fiducial mass of 440 kT A solution based on 12’’ PMT’s saves costs with same light as SK ongoing R&D for electronics (ASIC’s) and mechanics physicswise, MEMPHYS compares favourably to UNO and SK A full study on cavern + detector should be launched for EU FP7 in collaboration with liquid argon (GLACIER) and scintillator (LENA) Important milestone will be 2010 Physics would start before 2020 MEMPHYS welcomes all interested collaborators A document submitted to CERN council strategy group is available (see council-strategygroup.web.cern.ch/council-strategygroup/SGcontrib.html)

BACKUP

SUPERBEAM BETABEAM  → e e →   Superbeam + beta beam together 2 ways of testing CP, T and CPT : redundancy and check of systematics 2 beams 1 detector 2yrs 8yrs 5yrs pure4 flavours + K    

ASICs submissions MAROC : 64 ch multianode readout –64 fast digital outputs (2ns risetime) –Charge measurement with variable shaping –Gain adjustment (6bits) –3 Digital thresholds (10bits) –Submitted June 05 (SiGe 0.35µm ) MECANO2 –Large dynamic range variable gain preamps –Fast unipolar shaper for 100 MHz counting rate –Submitted June 05 (SiGe 0.35µm)

MAROC1: BLOCK FUNCTIONALITY DIAGRAM Complete front-end chip with 64 channels Submitted in June 2005 Expected in October 2005 Gain and Bandwidth flexibility: –Gain adjustment per channel (6 bits: 0 to 4) –Bipolar Fast Shaper: Gain=5mV/fC BW=10MHz –Unipolar Fast Shaper: Gain:5mV/fC BW:100MHz 3 thresholds: LSB=3mV, range=1V to 3.5V –Multiplexed charge measurement Peaking time with variable feedback network Tp=25ns to 200ns Hold signal Photomultiplicator Photons Variable Gain Preamp. Variable Slow Shaper S&H Bipolar Fast Shaper Unipolar Fast Shaper 64Trigger outputs Gain correction (6 bits) 4 discriminator thresholds (4*11bits DACs) Multiplexed charge output cmd_LUCID FS_choice LUCID Vth(Bip FS) = 2.3V Vth1(Unip FS)= 1.07V (1/3 pe-) Vth2(Unip FS)= 1.3 V (1.5 pe-) Vth3(Unip FS)= 1.7 V (3.5pe-)

Possible use of IPs (expensive) Huge effort started in in2p3/CEA –Several designs in institutes –10 bit pipeline ADC (LPCC) 10MHz –10 Bit C/2C SAR (LAL) 1 mW 1 MHz –10 bit FADC (LAL) 100 MHz –12 bit Wilkinson (CEA,LAL,LPCC) © J. Lecoq Integrating the ADCs : Pipeline ADC ©J. Lecoq100 MHz FADC ©V. Tocut