The SMRD subdetector at the The SMRD subdetector at the T2K near T2K near detectordetector station station

Marcin Ziembickirepresenting the SMRD working group

of the T2K collaboration

SMRD working group membersSMRD working group membersJ. Brinson, B. Ellison, R. Gould, B. Hartfiel, N. Kulkarni, T. Kutter, J. Liu, W. Metcalf, M. Nauman, J. Nowak, J. Reid, D. SmithJ. Brinson, B. Ellison, R. Gould, B. Hartfiel, N. Kulkarni, T. Kutter, J. Liu, W. Metcalf, M. Nauman, J. Nowak, J. Reid, D. Smith

Department of Physics & Astronomy, Louisiana State University, USADepartment of Physics & Astronomy, Louisiana State University, USA

D. WarnerD. Warner

Department of Physics, Colorado State University, USADepartment of Physics, Colorado State University, USA

I. Danko, D. Naples, D. Northacker, V. PaoloneI. Danko, D. Naples, D. Northacker, V. Paolone

Department of Astronomy and Physics, University of Pittsburgh, USADepartment of Astronomy and Physics, University of Pittsburgh, USA

L. Golyshkin, A. Izmaylov, M. Khabibullin, A. Khotjantsev, Y. Kudenko, O. Mineev, E. Shabalin, N. YershovL. Golyshkin, A. Izmaylov, M. Khabibullin, A. Khotjantsev, Y. Kudenko, O. Mineev, E. Shabalin, N. Yershov

Institute for Nuclear Research, Moscow, RussiaInstitute for Nuclear Research, Moscow, Russia

S. Aoki, T. Hara, A.T. Suzuki, T. YanoS. Aoki, T. Hara, A.T. Suzuki, T. Yano

Kobe University, JapanKobe University, Japan

D. Kielczewska, M. PosiadalaD. Kielczewska, M. Posiadala

Institute of Experimental Physics, University of Warsaw, PolandInstitute of Experimental Physics, University of Warsaw, Poland

M. Dziewiecki, R. Kurjata, J. Marzec, K. Zaremba, M. ZiembickiM. Dziewiecki, R. Kurjata, J. Marzec, K. Zaremba, M. Ziembicki

Institute of Radioelectronics, Warsaw University of Technology, PolandInstitute of Radioelectronics, Warsaw University of Technology, Poland

J. Blocki, A. Dabrowska, M. Sienkiewicz, M. Stodulski, A. Straczek, J. Swierblewski, T. WJ. Blocki, A. Dabrowska, M. Sienkiewicz, M. Stodulski, A. Straczek, J. Swierblewski, T. Waachachalla, A. Zalewskaa, A. Zalewska

H. Niewodniczanski Institute of Nuclear Physics PAN, PolandH. Niewodniczanski Institute of Nuclear Physics PAN, Poland

T. Kozlowski, J. Lagoda, P. Mijakowski, P. Przewlocki, E. RondioT. Kozlowski, J. Lagoda, P. Mijakowski, P. Przewlocki, E. Rondio, , R. Sulej, M. SzeptyckaR. Sulej, M. Szeptycka

A. Soltan Institute of Nuclear Studies, PolandA. Soltan Institute of Nuclear Studies, Poland

J. Holeczek, J. Kisiel, T. SzeglowskiJ. Holeczek, J. Kisiel, T. Szeglowski

Institute of Physics, University of Silesia, PolandInstitute of Physics, University of Silesia, Poland

J. SobczykJ. Sobczyk, J. Zmuda, J. Zmuda

Institute of Theoretical Physics, Wroclaw University, Institute of Theoretical Physics, Wroclaw University, PolandPoland

T2K Overview

• Measurement of 13 through e appearance

• Precise measurement of 23 and Δm2

23 through μ disappearance

295 km295 kmKamiokaKamioka TokaiTokai

Super-K Super-K 22.5 kt22.5 kt

(FV)(FV)

J-PARC Main RingJ-PARC Main Ring

750kW 750kW 330 GeV PS0 GeV PS

ND280 Off-Axis Detector• UA1/NOMAD CERNUA1/NOMAD CERN magnetmagnet

operated at ≤0.2 T magnetic field • Fine Grained Detector (FGD)Fine Grained Detector (FGD)

– Measure beam flux, E spectrum, flavor composition through CC -interactions

– Backgrounds CC-1– Measure backgrounds/pion cross section

– Water and scintillator target

• Time Projection Chamber (TPC)Time Projection Chamber (TPC) – Measure charged particle momentum,

particle ID via dE/dx

• Pi-Zero Detector (P0D)Pi-Zero Detector (P0D)– Optimized for NC 0 measurement

– Measure e contamination

• Electromagnetic Calorimeter (ECAL)Electromagnetic Calorimeter (ECAL)– Photon detection (from 0) in P0D and

tracker

• Side Muon Range Detector (SMRD)Side Muon Range Detector (SMRD)– Measure momentum for lateral muons

– Cosmic rays trigger

ALL detectors installed ALL detectors installed (except barrel ECAL)(except barrel ECAL)

TR

AC

KE

RT

RA

CK

ER

SMRDSMRD

SMRDSMRD

beam

Status: Status: COMMISSIONINGCOMMISSIONING

SMRD – Concept & Tasks• Measure muon momenta and angle from

interactions (with large angle to the beam)

• Cosmic trigger for the calibration of the inner detectors

• Beam monitor function is being studied 1.5E+6 interactions expected in the first year 100k will give events with hits in SMRD

• Background rejection

875mm

Modules:Modules:

• Horizontal (4 counters each)

• Vertical (5 counters each)

• Total of 440 modules (2008 counters)

SMRD Counters

S-shaped grooves with WLS fibers (Kuraray Y-11, S-type, 2.12 m length)

Light-tight enclosure & stainless steel containers

Special end-caps on both ends

Scintillator:Scintillator:Polystyrene1.5% PTP0.01% POPOP

Chemical reflector

Cosmic muon tests

cm

cm

p.e.

Light Yield (single counter)

Time Resolution & Delay(single counter)

TDC step50 ps

TD

C

cm

cm

L.Y. (center, 1000 counters)

• L.Y. (sum of both ends) 25-50 p.e. (center, T=20-22 C)

• Spatial resolution x = 6.1 0.8 cm

• MIP detection efficiency > 99.9%

SMRD Limit:SMRD Limit:L.Y.(sumL.Y.(sum of both ends) > 20 p.e./MIP at 20of both ends) > 20 p.e./MIP at 20 CC

SMRD ModulesOptical connector with MPPC:- Hamamatsu 667-pixel device,

- active area: 1.3x1.3 mm2, - pixel size 50x50 μm2, - bias voltage ~70 V, - gain ~7.5x105

Temperature sensor (DS18B20), (2 per module, opposite sides)

Scintillators in light tight, stainless steel enclosure

Aluminum profiles & fixing springs

48

48

17

Installation

Aluminum profilesSpringsInstallation tools

UA1 Magnet:UA1 Magnet:• 16 C-shaped elements (8 rings)• 16 48-mm thick iron plates for each C• 17-mm air gaps

Fixing Requirements:Fixing Requirements:• Feasible installation• No movement once installed• Protection from earthquakes

1 2 3 4 5 6 7 8

Installation (cont’d)

1) 2) 3)

4) 5)Installation summaryInstallation summary::• March July 2009• All modules tested

after installation

99.8% WORKING99.8% WORKING

Signal Readout

CHi

CLo

Cg

HV Trim

HV Bias

Cal. pulse

Trip-t

Mini-coax

MPPC

High gain channel

Low gain channel

Used by Used by SMRDSMRD

• Four Trip-t chips• 64 channels per board• HV for sensors• Timestamping• Possibility of channel pairing• Global trigger primitives

signaling

Trip-t Front-End Board (TFB)Trip-t Front-End Board (TFB)

FP

GA

MPPC Issues

Gain 105106

Quenching resistor

APD pixel in Geiger mode

Signal proportional to light intensity,

single photon ‘steps’

65 66 67 68 69 70 710

5

10

15x 10

5

T = 0 C

T = 10 C

T = 20 CT = 30 C

T = 40 C

T = 50 C

65 66 67 68 69 70 710

5

10

15x 10

5

Supply Voltage (V)

Ele

ctro

n G

ain

Example response

Gain vs Voltage vs Temp.• Small, insensitive to magnetic fields

• Relatively new sensor extensive testing was necessary

(revealed excellent sensor quality) nobody used it for long period (several years)

• Parameters highly dependent on temperature

Monitoring requiredMonitoring required

0 p.

e. 1 p.

e.2

p.e.

On-Line MonitoringBasic requirementsBasic requirements• Real time information analysis• Raising diagnostic (Audio-visual) alarms• Providing preliminary help for non-experts

On-going workOn-going work Channel histograms Gain & dark rateso Temperature datao Per-channel historyo Detailed alarmso Threshold settingso Physics data quality

monitoring

Reconstruction• Select pairs of hits in coincidence window ~25ns

(max. time of the signal propagation through the fibre, plus est. time readout uncertainty)

• Reconstruct hit position(only z-axis, along the scintillator, based on the time difference)

• Cosmic tracks – 3D fit to the reconstructed hits (Principal Component Analysis, straight line)

• Various reconstruction approaches are being pursued for beam events.

ND280 software v7r5

all hits hits in coincidence

ReconstructionMonte Carlo StudyMonte Carlo Study

ND280 software v6r1

Side view Front view

Straight track, good fit

track bent, poor fit

Example 1

Example 2

Reconstruction Error(maximum distance of the reconstructed track to the real track)

distance (mm)

no.

of t

rack

s

Cosmic muon trigger Purpose: Purpose:

Test and calibration (SMRD & inner detectors) Based on signals from SMRDBased on signals from SMRD

Also the downstream ECAL and first layers of P0D are used

Trigger algorithm:Trigger algorithm: Signals from both sides of the scintillator (coincidence

gate: 30 ns) At least two such coincidences from one tower Signals from two (or more) towers from different walls

(coincidence gate: 200 ns, because of the flight time)

Cosmic Muon Trigger Simulation Steps of the simulation:Steps of the simulation:1. Muon flux on the Earth surface

2. Propagation through the rock surrounding the pit

3. Propagation through the detector

4. Simulation of the electronic signals

5. Applying of the trigger conditions

ND280 simulation packagebased on GEANT 4

Simulation can be used for both closed and open magnet positions

PPreliminary studies show reliminary studies show cosmics simulation and cosmics simulation and data to agree welldata to agree well

Summary• Installation complete in July 2009• On-line monitoring partially done• Data taking seems to work, already

reconstructed cosmic muons tracks• Current efforts:

– Monitoring beam structure– Reconstruction (different approaches)– Simulation– Cosmic trigger– Calibration– Slow control