A new tile calorimeter with Silicon Photomultipliers for the KLOE-2 experiment

A new tile calorimeter with Silicon

Photomultipliers for the KLOE-2 experiment

Ivano SarraUniversity of Tor Vergata

Laboratori Nazionali di Frascati

Young Researcher Program @ Frascati Spring School 2008

LNF- Frascati ( 13-5-2008)

Summary of the existing QCALSummary of the existing QCALOutline Outline

- The proposal of a new quadrupole calorimeter QCALT

- A new kind of device: the SIPM

- Test on SiPM (Hamamatsu MPPC)

- Test on different fiber types

- Tests on Tiles

- Conclusions

To recover photons lost on the quadrupole region the area is covered by a Tile Calorimeter QCAL

Summary of the existing QCALSummary of the existing QCALSummary of the existing QCALSummary of the existing QCAL

For the neutral decay of KL ―› 2π0 ―› 4γ

At KLOE the measurement of direct CP violation is possible through the double ratio: R = (KL +) (KS 00) / (KS +)(KL00)

ivan

piombo=leadwave long shifterspessore=thick

Proposal of new QCALProposal of new QCAL

- Barrel with 12 modules

- Each module has a thickness of 5-6 cm and 1 m length. It is made by 8 layers of 2 mm W /3 mm Scint.

Along Z, each slab is divided in 20 tiles of 5x5 cm2 Tile dimension increases along R.

For the high precision measurement of KL20 decay rate- Adapt a new calorimeter over new interaction region- Improve granularity, time resolution & efficiency.

Z

ZR

Proposal of new QCALProposal of new QCAL

ivan

square centimenter

New tiles designNew tiles designThe R&D for Tesla/ILC made possible a very promising tile detector: - Square tiles with fibers in circular grooves.- Tile readout is possible with SiPM

New tile designNew tile design

SIPM =SILICON PHOTOMULTIPLIERArray of Single Geiger Mode APD. It is a discrete detector for photon counting depending on the PIXEL size

MPPC = SIPM by Hamamatsu 1 mm^2 area 100 pixels --> 100 um 400 pixels --> 50 um

Test on SiPMTest on SiPM

First study on SiPMFirst study on SiPMFirst study on SiPMFirst study on SiPM

To study SiPM characteristics we use:- Black box - Pulsed led to fire SiPM- Polaroid filter to change light intensity

We can measure:- Gain vs Vbias- Gain vs Temperature- Dark noise rate

SIPM signal with BLUE Led PulserSIPM signal with BLUE Led PulserFrom From Scope:Scope:

From Adc:From Adc:

Vbias 69.25Volt, T:24°CVbias 69.25Volt, T:24°CRise Time Rise Time ~~33ns, ns, Fall Time Fall Time ~~150ns150ns

From ADC spectra, we get From ADC spectra, we get single photoelectron single photoelectron charge (charge (Vbias 69.25, Vbias 69.25, T:24°CT:24°C):):Q = 0.36pCQ = 0.36pCGain = Gain = 2.3E+062.3E+06

Δcount=17.4Q’=17.4*0.25pC=4.35pCQ=4.35/11.8(ampl.)=0.36pCG=Q/e

0pe1pe

2pe3pe

4pe

Gain vs TGain vs T

ΔΔG = -0.12 G = -0.12 ΔΔTT

ΔΔG=-0.12 G=-0.12 ΔΔTT

Vbias=69.30Vbias=69.30VV

Our result

Hamamatsu

Dark Count vs VbiasDark Count vs Vbias

Our result

Hamamatsu

Dark

-Cou

nt(k

Hz)

Test on Test on fibersfibers

Test of single Scintillating Fibers Test of single Scintillating Fibers We have studied the characteristics of 3 different types of fibers:

- Kuraray SCSF 81 (Blue )- Saint Gobain BCF92 single cladding (Green)- Saint Gobain BCF92 multi cladding (Green)

The test is performed using SiPM and a beta source of Sr90.

The trigger is provided by a NE110 finger (1cm x 5cm) readout by 1” PM.

SiPM + electronicsfiber

Sr90

NE110 PM

Trigger

Selected Scintillating FibersSelected Scintillating Fibers

After the test we have selected: Saint-Gobain Multi Cladding fibers:

1) Best light yield

2) Fast emission time (3-4 ns/p.e.)

3) High attenuation length (3.5 m)

Q( ADC COUNTS)

Test on tilesTest on tiles

Test of tilesTest of tiles

3 possible solutions under study: 1) SIPM directly on tile 2) SIPM + amplifier + HV on tile 3) SIPM connected to fibers in a far-away position from tile

At the moment we have tested only the third solution:

- Tiles: 3mm and 5 mm thickness

- Without reflector at fiber end

- Simple mylar around tile

- SiPM placed outside tile in optical contact (w grease) with fiber.

Test of TilesTest of Tiles Data taking with cosmic rays. Trigger using 2 scintillator counters read at both ends.

Tested 2 tiles with different thickness and different SIPM.To investigate the use of SIPM@400 pixels (vs SIPM@100 pixels) which has: a gain reduction of 1/3 (7.5 10+5 instead 2.4E10+6) a reduced temperature dependence G = -0.03T (instead -0.12)

SiPM + electronics

NE110

TriggerTile

Fiber

Scintillator

Test of Tiles (MIP distribution) Test of Tiles (MIP distribution)

ADC distributions for two different thicknesses

The MIP values are compatible taking into account different thicknesses and QEof the two SIPMs.

N3mm = N5mm x 3/5 x 0.40/0.45

N3mm ~ 14

3mm thick400 Pixels SIPM<MIP> = 14 pe

5mm thick100 Pixels SIPM<MIP> = 26 pe

Tile test (time resolution for MIP)Tile test (time resolution for MIP)

After correcting the pulse height dependence on the timing, a Time Resolution of 750 (1000) ps is obtained for a MIP on the 5 (3) mm thick tiles.

No correction applied to the trigger jitter.

TDC ( Counts)

110 ps/counts

5 mm thick 3 mm thick

Conclusions and plansConclusions and plans

SiPM: our tests confirm Hamamatsu characteristics for 100 pixels MPPC:- Gain vs HV- Gain vs temperature - Dark noise

Reduced temperature variation of gain and dark noise expected for a 400 pixels MPPC (50 m pixel).

Fibers: adopted solution is the Saint Gobain multi cladding.

Tile: Good results on light response and timing. Light yield and time resolution sufficient for our purposes. Solution with MPPC+amp directly on tile under development.

Spares

Set UpSet Up

- HV stability 10 mV- HV stability 10 mV

- Blue LED diode on - Blue LED diode on SiPMSiPM

-Temperature Temperature measuredmeasured on SiPMon SiPM

- CAMAC DAQCAMAC DAQ

- ADC sensitivity ADC sensitivity 0.25 pC/cnt0.25 pC/cnt

Mppc: Multi Pixel Foton CounterMppc: Multi Pixel Foton Counter•

Mppc: Multi Pixel Foton Counter -100C N.370, characteristics at 25°C and Mppc: Multi Pixel Foton Counter -100C N.370, characteristics at 25°C and λλ=655 nm:=655 nm:

Vop. 69,28V, Gain 2.41E+6Vop. 69,28V, Gain 2.41E+6

The KLOE experiment

Superconducting coil B=6kGauss

Electromagnetic CalorimeterMeasure charged particles

lead/scint. fibers 4880 PM

Drift Chamber Measure charged particles

(4 m thick 3.4 m lenght) 90% He; 10% iC4H10 52140 wires

The KLOE design was driven by the measurement of direct CP violation through the double ratio: R = (KL +) (KS 00) / (KS +)(KL00)

Collision at sqrt(s)=Mphi = 1.02GeV• (e-e+)―› Φ ―› (kS kL) (k- k+)

ivan

Istallazione del calorimetro. Si vedono i primi 7 moduli del calorimetro centrale, 4 m in lunghezza, posizionati all'interno del cilindro che costituisce il magnete solenoidale di KLOE.

ivan

Le dimensioni sono dettate dalla necessità di ricostruire i decadimenti di particelle, i KL, il cui cammino medio prima di decadere, in KLOE a DAFNE, è di 3,4 m.

ivan

costruito intervallando strati di fibre scintillanti a sottili fogli di piombo, per ottenere una struttura ad un tempo compatta e semitrasparente.Grazie al calorimetro possono essere rivelate tutte le particelle neutre, come per esempio i fotoni, che sfuggono alla rivelazione della camera a deriva. Il calorimetro è in grado di fornire misure di tempo particolarmente accurate che permettono di identificare con precisione, dalle misure di tempo di volo, i Kaoni neutri, gli elettroni, i pioni. La sua risoluzione temporale, che dipende dall'energia rilasciata, è di circa 100 ps in una vasta regione di energie di interesse per l'esperimento.

ivan

La camera a deriva rivela le particelle cariche prodotte dalle collisioni tra elettroni e positroni di DAFNE, permettendo la ricostruzione delle loro traiettorie. La curvatura indotta dal campo magnetico di KLOE consente, inoltre, di misurarne la quantita' di moto. L'accuratezza della misura dipende dalla precisione con cui si ricostruisce la traiettoria in campo magnetico e dall'entità dei fenomeni di dispersione subiti dalla particella che attraversa la camera. Per minimizzare i processi di dispersione, che dipendono dal numero atomico (Z) del materiale attraversato, la camera viene fatta funzionare con una miscela ricca di He (Z=2). La risoluzione ottenuta, che dipende dall'angolo della traiettoria con il campo magnetico, θ, è del 4 per mille in una vasta regione di valori di θ.

Dark Count shape vs VbiasDark Count shape vs Vbias

T = 24 °CT = 24 °C

• V=R*I=R*Q/τ, Where: τ = 35ns R = 50Ω

•Dark rate follows •specifications.•It becomes negligible•when triggering at•1.5 pe.

Vbias 68.90V Vbias 68.97V0.5pe 470kHz1.5pe 34kHz

0.5pe 530kHz1.5pe 40kHz

Vbias 69.03V Vbias 69.09V0.5pe 610kHz1.5pe 58kHz

0.5pe 680kHz1.5pe 85kHz

Tile testTile testTime resolution measured using different number of photoelectrons on tile.

4.8 0.37tpe

ns nsN

σ = ⊕

Result compatible with 5mm tile.

No trigger jitter corrected.

Stochastic term roughly consistent with:

( )int

int

3.5 2.5

4.3fib sc

fib sc

ns

ns

τ τ

τ τ

⊕ = ⊕⊕ =

Fibers testFibers test

Saint Gobain multi cladding

- Pedestal- Cut @ 0.5 pe- Cut @ 1.5 pe

0pe

1pe

2pe

3pe4pe

5pe


Saint Gobain single cladding


0pe

1pe

2pe

3pe4pe


Kuraray Y11


0pe

1pe

2pe

3pe

Tile testTile test

ADC distribution obtained using a 3mm tile optically coupled with a 400 pixels SiPM.

ADC counts

0pe

1pe

Entri

es

Tile testTile test

Using 3mm tile with 400 pixels MPPC.

Slewing correction.

Fit function:

00 ped

Bt Aa a

= +−

Charge of imput signal [ADC counts]

TDC Vs ADC

ivan

Apd operanti in Geiger ModeApd operanti in Geiger Mode

tt0

iimax

t1

Diodo a Vbias > VbdDiodo a Vbias > Vbd• t < tt < t00 ... i=0, non ci sono portatori ... i=0, non ci sono portatori• t = tt = t00, inizia la valanga, inizia la valanga• tt00 < t < t < t < t11, la valanga si diffonde, la valanga si diffonde• t > tt > t11, la valanga si auto-sostiene , la valanga si auto-sostiene ed è limitata ad Imaxed è limitata ad Imax dalle resistenze dalle resistenze in seriein serie

Meccanismo di QuencingMeccanismo di Quencing

VbiasVbias

VbdVbd

Apd operanti in Geiger Mode Apd operanti in Geiger Mode

Gli Apd operanti in geiger mode possono essere modellati Gli Apd operanti in geiger mode possono essere modellati tramite il seguente circuito elettronico:tramite il seguente circuito elettronico:

• Switch OpenSwitch Open: quando la valanga : quando la valanga non è innescata Cnon è innescata Cdd si carica a V si carica a Vbiasbias e e non scorre correntenon scorre corrente• Switch Close: Switch Close: quando la valanga quando la valanga si innesca Csi innesca Cdd si scarica fino a V si scarica fino a Vbdbd con con ττ=R=Rss*C*Cdd e la corrente va ad e la corrente va ad I=(VI=(Vbiasbias-V-Vbdbd)/R)/RQQ

ττQQ=R=RQQ*C*Cd=35nsd=35ns

Gain vs Vbias.2Gain vs Vbias.2

Our measurement:Our measurement:

From Hamamatsu:From Hamamatsu:

Gain vs VbiasGain vs VbiasGate: 350nsGate: 350ns T=24°CT=24°C

Vbias 68.60V Vbias 68.66V Vbias 68.70V


ADC spectra as a function of the applied HV.

Gain vs VbiasGain vs VbiasIncreasing HV we increase dark rate



Gain vs VbiasGain vs Vbias

ΔΔG=2.24 G=2.24 ΔΔV V ΔΔG=2.19G=2.19ΔΔVVΔΔG=2.12G=2.12ΔΔVV

ΔΔG=2.25 G=2.25 ΔΔVV

Our result

Hamamatsu

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A new tile calorimeter with Silicon Photomultipliers for the KLOE-2 experiment