1 Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010 PANDA Detector and Recent Development on DIRC & SiPM Bidyut Roy NPD, 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
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PANDA Detector and Recent Development on DIRC & SiPM Bidyut Roy NPD, BARC, Mumbai
PANDA Detector and Recent Development on DIRC & SiPM Bidyut Roy NPD, BARC, Mumbai. An overview of FAIR accelerator Complex Over view of the PANDA detector Indian interest: Luminosity monitor and - PowerPoint PPT Presentation
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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
2Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
7Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
8Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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.
9Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
10Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
11Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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 ?
12Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
13Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
14Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
Work Bench for SiPM Test@GSI
Pico-second diode laser
λ = 660 nm
+
Green LED 460 nm
Discr. scaler
15Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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)
16Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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)
17Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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.
18Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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)
19Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
20Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
21Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
SiPM: in-beam test results…
R (
Sig
nal
+B
G )
/ B
G
Bar angle w.r.t. beam
Coincidence between G-APDs
22Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
23Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
30Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
Lumi. Monitor
Status: simulation for geometry realization & BG studies…….
• GSI, University Mainz, FZ-Juelich & Indian group:
• BEL, Bangalore:
31Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
32Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
33Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
BaBar
DIRC (Detection of Internally Reflected Cherenkov light)
BaBar 11000 PMT
PANDA 7000 PMT
Compact design
34Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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.
36Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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)
37Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
• 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
38Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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
39Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
MCP Planacon/Burle 85011
Dual MCP
Anode
Gain ~ 106
Photoelectron
photon
Faceplate
Photocathode
Multi anode 64 Pins
Dimensions:
40Bidyut Roy (BARC ) Strong Int. in 21st Century, TIFR, Feb.2010
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)