panda detector and recent development on dirc & sipm bidyut roy npd, barc, mumbai

1Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010

PANDA Detector and Recent Development on DIRC & SiPM

Bidyut RoyNPD, BARC, Mumbai

• An overview of FAIR accelerator Complex

• Over view of the PANDA detector

• Indian interest: Luminosity monitor and

DIRC Cherenkov & SiPM

• SiPM : recent activities and test results

• An overview of FAIR accelerator Complex

• Over view of the PANDA detector

• Indian interest: Luminosity monitor and

DIRC Cherenkov & SiPM

• SiPM : recent activities and test results


The PANDA The PANDA CollaborationCollaboration

U BaselIHEP BeijingU BochumIIT BombayU BonnIFIN-HH BucharestU & INFN BresciaU & INFN CataniaJU CracowTU CracowIFJ PAN CracowGSI Darmstadt TU DresdenJINR Dubna (LIT,LPP,VBLHE)U EdinburghU ErlangenNWU Evanston

U & INFN FerraraU FrankfurtLNF-INFN FrascatiU & INFN GenovaU GlasgowU GießenKVI GroningenIKP Jülich I + IIU KatowiceIMP LanzhouU LundU MainzU MinskITEP Moscow MPEI MoscowTU MünchenU MünsterBINP Novosibirsk

IPN OrsayU & INFN PaviaIHEP ProtvinoPNPI GatchinaU of SilesiaU StockholmKTH StockholmU & INFN TorinoPolitechnico di TorinoU Piemonte Orientale, TorinoU & INFN TriesteU TübingenTSL UppsalaU UppsalaU ValenciaSMI ViennaSINS WarsawTU Warsaw

Presently about 400 physicists from 53 institutions in 16 countries

PANDA Det. ~ 66 M euro Indian Contribution


PANDA: Indian groupIndia - PANDA collaboration

Activities:

• Silicon strip det. (Luminosity monitor)

• Cherenkov det. & photon counter (SiPM)

• Detector simulation & physics simulations

• Data analysis

• Theoretical study

Present Group:BARC-Mumbai (NPD, ED) IIT Bombay,

SINP-Kolkata,IIT Indore,IIT- Gauhati, Pune university,AMU Aligarh, AligarhSouth Gujrat Univ.-Gujrat,

TIFR- Mumbai,NIT Jalandhar, MSU Vadodara, Magadh University, VECC-Kolkata,


Facility for Antiproton and Ion Research

CBM

Rare IsotopeProduction

Super FRS

NESR

RESR/CR

HESR

PANDA

SIS 100/300

FLAIRPlasma/Atom Physics

p-LinacSIS18Existing GSI

100m

UNILAC

Heavy ion synchrotron SIS18: 1–2 GeV/u beam: 1012/s

Future SIS100/300 (circumference: 1100 m)Upto 29 GeV/u + Secondary beam (RIB, p(bar))NuStar, CBM, PANDA

HESR: 1–15GeV/c(cooled beam), √S <= 5.46GeVI = 5. 1010/sec,+ pellet target L = 2.1032 cm-2 s-1


Detector Requirements

• 4π acceptance . High rate capability (2x107 s-1 interaction)

• Good momentum resolution & particle identification for p, π, k, e, µ, γ

• Good tracking & vertex reconstruction capability


PANDA Spectrometer: overview & possible Indian contribution

Barrel DIRC:Photon Counter + + Simulation

Barrel TOF ? Endcap Disk DIRC:

Forward TOF

Forward RICH

Muon Det. Luminosity Monitor

Target: Pellete (H, D.. )Nuclear: Foil, thin wire

Calorimeter:EM + Hadron,muon chamber

Beam

Target spectrometer: θ> 5 deg. Located inside a solenoid, l=2.5 m, Ø= 0.8 m, B~ 2T

Forward spectrometer: θ< 5 deg. (vertical) & < 10 deg. (horizontal)


PANDA Cherenkov detector for PID

PANDA needs excellent particle identification

over wide momemtum range:• p: 200MeV/c – few GeV/c different PID techniues are

needed

PID Processes:

• Energy loss: & time of flight (p < 1 GeV )

• Cherenkov radiation (p > 1 GeV)

Particle identification:

• Cherenkov photon angle velocity

• tracking detector p Mass

Cherenkov radiation: principle A charged track with velocity v=βc exceeding the speed of light c/n in a medium with refractive index ‘n’ emits Cherenkov light at a characteristic angle,

cos θ = c/nv = 1/β n•nβ < 1 below threshold > no radiation• nβ> 1 Cherenkov radiation


Cherenkov Detector for PANDA:

DIRC (Detection of Internally Reflected Cherenkov light)

Two DIRC like counters are considered for PANDA experiment: Barrel DIRC: concept from BaBar, DISC DIRC/end-cap:

17mm x 35mm, few meter long

Concept taken from BaBar DIRC det.


BaBar 11000 PMT

PANDA DIRC: possible solution

Panda DIRC: possible solution

PANDA 7000 PMT

Compact design

Option A Option B

Radiator (for PANDA solid radiator) : quartz / plexi-glass

Focusing element

Photon detection system: PMT (BaBar),

new idea: MCP-PMT, SiPM


SiPM: The next generation photon counter

Title

• Advantages & week points

• Test set-up

• Results from different SiPMs

& Spectral sensitivity measurement

• In-beam test of Cherenkov radiator

With SiPM with MCP-PMT


SiPM as photon counter….

SiPM is a p-n junction diode that is biased above the break-down voltage in order to create a Geiger avalanche – ‘Geiger APD’? Can we use such Geiger mode APD as photon detector for DIRC ? Can they replace PMT

Advantageous: + insensitive to magnetic field

+ high photon detection efficiency over wide spectral range (~65% @400nm), single photon sensitivity

+ gain comparable to PMT (~ 2x105 - 106)

+ no high voltage ( < 100 V) + good time resolution ( < ns)

+ easy to handle and compact in size + potentially cheap (?)

Disadvantageous:- relatively large dark count rate (few 100 kHz/mm2) with single photon pulse height (noise reduction: Cooling! )

radiation hardness needs to be tested ?


G-APDDifferent G-APDs are available, we have worked with

Hamamatsu MPPC, Zecotek MAPD

Operation principle:

Photon absorbed produced electron – hole pairsget accelerated by high electric fieldproduce further secondary e--hole pairsavalanche multiplication

When reverse bias set higher than breakdown voltage, huge gain (~106) can be obtained Geiger mode operation.

Signal Q = C x (Vbias - Vbr), C: pixel capacitance


G-APD ….

Passive quenching by resistor

Pixel recovery time ~100 ns given by time constant to re-charge the pixel’s capacity

Geiger modeeach pixel acts as digital device with o/p independent of no. of photons absorbed

But when all cells are connected in parallel SiPM becomes an analog device allowing no. of photons to be counted


Work Bench for SiPM Test@GSI

Pico-second diode laser

λ = 660 nm

+

Green LED 460 nm

Discr. scaler


SiPM test results…

Typical MPPC spectrum triggered by laser (photograh taken from digital scope)

Time

No. of p

hotons

Dark count measured:

S10362-11-100C, VB=+70V, room Temp.: @0.5 p.e. 500kHz , @1.5 p.e. 60 kHz (in agreement with the specifications provided by the supplier)

But they are noisy (as compared to other photon counter e.g., PLANACON MCP-PMT 85011, ~ few hundreds / sec)

due to operation in Geiger mode, nose get amplified

Noise usually at level ~ 1 p.e. not a problem for a measurement where large nr. of photons are detected

Dark current reduction in lowering temp.!

Gain (from ADC spectrum)

= (Channel nr. between two peaks) X (ADC resln (fC/ch) ) X (1/q)

~ 2.7 x 105 – 2.4 x 106 (Ref. Hamamatsu)


Spectral response characteristic of SiPM

Monochrometer @Frankfurt univ. λ = 200 – 800 nm

G-APD holder mounted inside a dark box

attenuator

Photon Detection Efficiency (PDE):

• Photo-diode(PD) with known photo sensitivity (mA/W) measure photocurrent no. of incident photons at each λ can be obtained

• Next: replace PD by SiPM at same position repeat the measurement gain at that voltage should be knownDetected photon nr. can be obtained (=current/gain/q)

• PDE= (no of detected photon / no of incident photon) X (PD area / SiPM area)


Photon Detection Efficiency (PDE) of SiPM

QE= quantum efficiency,

Pavalanche = avalanche probability = (nr. of excited pixels)/(nr. of photon-incident pixels)

Fgeo = effective pixel size / total pixel size

(usually small due to space needed for quenching resistance, Typically 30% for pixel nr. 1600 (i.e., 25micron), 61% for pixel 400 (i.e., 50micron) and 78% for pixel 100 (i.e., 100 micron)

Small nr. of pixels has better geometric factor but also lower dynamic range (as prob for multi-photon hit in same pixel increases) there is a trade off between dynamic range and PDE

Photon detection efficiency is a measure that indicates what percentage of incident photons is detected.


SiPM: PDE measurement

Measured simultaneously with a Silicon PIN diode which was calibrated by the supplier

MAPD-3N

Normalised with PDE=32.4% at 450 nm from PSI data

Normalised with PDE=24.5.4% at 450 nm from Dubna data

Our data

MPPC- 100μ

PSI data

Hamatsu data

Future work:

-- down to below 300 nm

-- Dark current under cooling

-- Radiation hardness test

(using facilities BARC/Mumbai)


In-beam test of DIRC Cherenkov radiator with SiPM & MCP-PMT: a very first report

proton beam, 2GeVSpill length = 5s (3 +2)Trigger ~ 50k/spillJoint venture with CBMParasitic run with CBMMain user:FOPI

CBM

DIRC bar with SiPM

Glasgow

GSI DIRC bar with MCP- PMT

Scintillators at several places: triger

Giessen Detector


SiPM: in-beam test results

Plexi glass: 15mm X 20mm X 70mm(long)

Position of SiPM: 1,2 : 28 mm

3,4 : 44 mm from radiator

Position simulation studies

60


SiPM: in-beam test results…

R (

Sig

nal

+B

G )

/ B

G

Bar angle w.r.t. beam

Coincidence between G-APDs


SiPM: in-beam test results…Very first conclusions

● We have seen Cherenkov light with SiPM

● Focusing light guide working

● We see coincidences between G-APDs

Acknowledgement to the Giessen group and all involved


DIRC prototype with MCP: GSI beam test

Quartz Bar length: 800 mm, n=1.47

Oil: Marcol 82, n=1.46

MCP (Planacon 85011)

Area~ 51 mm X 51 mm

8x8 = 64 pixels (each 6 mm x 6mm

Bialkali photo cathode, spectral range~ 185 – 660 nm


GSI beam test: Preliminary data


Next step: Bar shifted



Luminosity Monitor : Indian contribution

Concept for Lumi. Det.:

In order to determine cross section for a physical process, it is essential to measure the time integrated luminosity L.

p(bar)+p collision elastic cross section are not know that accurate:

Coulomb part and nuclear part(?)

(unlike e++e- scattering where theoretical Bhabha scattering is well known.)

This demands extreme forward angle measurement close to beam axis where cross section is mainly Coulomb scattering

(measurement at such forward angle is a formidable task !)


Luminosity Monitor ……..

Initial thought: use Si-Strip detectors (expertise available, radiation hard )

Requirement:

Four planesTrapezoidal (or Disk) shapeEach plane 4 sensorsDimension: 2 cm(short side) / 5.33 cm(long side); X5 cm(height) X 150-200 μm (thickness);

Double side stripped, pitch ~ 50 μmDistance between planes: 20cm.

4-planes for sufficient redundancy and back-ground suppression

~ 10 m away from target

~ 3 – 8 mrad coverage

Strip on Front/Back Side, pitch = 50 μm

FrontSideFrontSide

BackSideBackSide


Lumi. Monitor

Status: simulation for geometry realization & BG studies…….

• GSI, University Mainz, FZ-Juelich & Indian group:

• BEL, Bangalore:


Summary:

• FAIR going to be an unique facility for many research fields and the PANDA program at FAIR will deliver significant & important contributions to our understanding of hadron physics

• The PANDA Detector will be a versatile large acceptance spectrometer that will provide– Tracking information and vertex reconstruction capability– Efficient particle identification & separation using Cherenkov

detector

• SiPM a promising tool for the use as photon counter: R&D activities

• India – PANDA collaboration interest:

hardware: Si-strip det. and Cherenkov det. & SiPM

Det. Simulation & Physics simulation

Theoretical study


BaBar

DIRC (Detection of Internally Reflected Cherenkov light)

BaBar 11000 PMT

PANDA 7000 PMT

Compact design


Time Resln: pulsed diode laser, pulse width: 50 ps, power pW = ? photons

MPPC

1p5 ps

PID sim. With Cherenkov DIRC:pp(bar)J/ψ+Φ(1020), Phi K+K- (BR~50%) and pion mode(BR~15%)Mom.res. From tracking det. GoodFor DIRC, theta resln 2mrad, no of Cherenkov photons =16(for BaBar det. Similar resln was obtained, PMT ~1” but distance was large 1.1m)

• PANDA dirc bar : 2 m long (3 pieces make 2 m long, as machining/polishing of a such long bar is not possible). For babar also they joined several bars to make 5 m long. For babar, pmt were 1.1 m away from bar end.

• Fish tank: quartz window/ container that contains marcol liquid (1.46 matching as that of quartz radiator 1.47). Lens at the end of bar and small air gap between lens and quartz window. Easy to dismount/change etc… also between fish tank window and MCP, 2mm air gap for easy removal etc.

• Overall panda det resln~ 1%, beam mom. Res. Δp/p~ 10-4 to 10-5 (cooled beam)

• For Cherenkov PID theta resln~ 2 mrad combining with good mom. Resln from tracking det (Δp/p ~10-3, cooled beam) good particle separation between k and pion upto 3 GeV/c can be obtained.

Δθ= 2mrad spatial resln ~ mm (at photon det. Plane which s about 30 cm away):

SiPM wih 1 mm2 area should do the job.

• Rate: 2x 10^7 interactions/sec =20MHz ave. charged particle multiplicity ~3 (could be less for DIRC 22 deg – 140 eg. As cmpared to FD.)

• Typical Cherenkov photons ~ 100/ cm of radiator for 1 GeV particle then loss etc…will make only few photons per SiPM. Simulation to be done.

• Radiation dose: charged particle:fixed target expt.->FD will see maximm charged particle (due to the Lorentz bost), lum~10^32, int.rate =20MHz integrated dose for few years running ~100krad so for Si-strip det (lumi mon. maximum dose

but SiPM , because sittinfg at backside), get less dose.

For frozen H arget, neutron production is less but when use nuclear target, significant neutron production take occur ->> simulations to be done.


Hadron Physics at PANDA

• Charmonium (C C¯) spectroscopy

• Search for QCD predicted Gluballs& Hybrids

• Modification of meson(D) properties in nuclear medium

• Rare decay & symmetry violation PANDA@FAIR: Lepton number violating decay in Do, D± ( < 10-4)


• Spectroscopy for single and double hypernuclei (hyperon- nucleon, hyperon-hyperon interaction)

Program at JPARC, Japan: 12C(K-, K+)12Ξ-Be

Elementary process:

K- p

K+ Ξ

-

Aim: Ξ-nucleus interaction

Λ-Λ interaction (Ξ-p ΛΛ)

Any information on Ξ-A would be useful


High Energy Storage Ring (HESR)

• Production rate: 2 x 107/sec

• pbeam = 1.5 ... 15 GeV/c

• Nstored = 1 £ 1011 p

• Internal Target• Electron and Stochastic Cooling

• High Luminosity Mode– p/p ~ 10-4

– L = 2 x 1032 cm-2s-1


MCP Planacon/Burle 85011

Dual MCP

Anode

Gain ~ 106

Photoelectron

photon

Faceplate

Photocathode

Multi anode 64 Pins

Dimensions:


Luminosity Monitor : Indian contribution

Concept for Lumi. Det.:

In order to determine cross section for a physical process, it is essential to measure the time integrated luminosity L.

p(bar)+p collision elastic cross section are not know that accurate:

Coulomb part and nuclear part(?) (unlike e++e- scattering where theoretical Bhabha scattering is well known.)

(At very small t σCoul ~ 98% for 15 GeV/c

momentum transfer ) σCoul ~ 95% for 3 GeV/c

Extreme forward angle measurement (A formidable task)

panda detector and recent development on dirc & sipm bidyut roy npd, barc, mumbai

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