short overview of lip-coimbra activity in view of 1 - rpcs for time-tagged tracking and

Short overview of LIP-Coimbra activity in view ofShort overview of LIP-Coimbra activity in view of

1 - RPCs for time-tagged tracking

and

2 - GEMs for high sensitivity L-Xe experiments

2

RD51 Paris – 13/Oct/2008 R. Ferreira Marques

WG2 - COMMON CHARACTERIZATION AND PHYSICS ISSUES

1) Generic aging and material radiation-hardness studies

WG3 - APPLICATIONS + WG4 – SIMULATIONS S/W TOOLS

1) MPGD based RPCs for tracking and ToF

2) Medical applications

1 – RPCs: Commitments within RD51

3


1 - RPCs for time-tagged tracking ... Long list of authors (see next slide)

Early work (ALICE TOF, 1999) 1.1 – Timing RPC (tRPC)

Developments 1.2 – Larger and still fast 1.3 – High count-rate (CBM) 1.4 – HADES ToF wall 1.5 – Localization capability 1.6 – Small animal PET

Goal within RD51 1.7 – Pixelized RPC TOF tracker (the concept)

4


A. Blanco1, N. Carolino1, C.M.B.A. Correia2, M.Couceiro1,5, L. Fazendeiro1, Nuno C. Ferreira3, M.F. Ferreira Marques4,5, R. Ferreira Marques1,6, C. Gil4, M. P. Macedo2,5

1 LIP, Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516 Coimbra, Portugal.2 CEI, Centro de Electrónica e Instrumentação, Univ. Coimbra, 3004-516 Coimbra, Portugal.

3 IBILI, Instituto Biomédico de Investigação de Luz e Imagem, Faculty of Medicine, 3000, Coimbra Portugal.4 ICEMS, Departamento de Física, Universidade de Coimbra, 3004-516 Coimbra, Portugal.

5 ISEC, Instituto Superior de Engenharia de Coimbra, 3031-199 Coimbra, Portugal6 Departamento de Física, Universidade de Coimbra, 3004-516 Coimbra, Portugal.

A.Blanco N.CarolinoO.CunhaP.Fonte L.Lopes A.PereiraC.SilvaC.C.Sousa

D.BelverP.CabanelasE.CastroJ.A.GarzónM.Zapata

D.GonzalezW.Koenig

J.DiazA.Gil

HADES-RPC group

RPC-PET team

RPC work teams

5


-HV

Resistive material, black glass

~2-3 1012 cm

Main features

• Timing resolution ~ 50 ps σ.

• Efficiency 75% for a 300 μm gap

• No energy resolution.

• Possibility to measure the position.

Sensitive Region

Particle

MIPS

Conductive material, Al

Gas gap

E

Precise gas gap with few 100 m

3x3 cm2

~1 pC ~3 ns

1.1 Timing RPC (tRPC) – the 1st prototype

6


3

2 26 8 4 9 4 7t ps

Resolution of thereference counter

[ F

onte

200

0]

= 99.5 % for MIPs(75%/gap)

-HV

4 x 0.3 mm gaps

Aluminum Glass

(optimum operating point 1% of discharges)

3x3 cm2

1.1 Timing RPC (tRPC) – the 1st prototype

Sharp timing but sm

all

7


Active area = 10 cm160 cm = 0.16 m2

(400 cm2/electronic channel)

5 cm 4 timingchannels

1,6 m

Top view Cross section

Ordinary 3 mm “window glass” ~81012 cm

Copper strips

HV

[Bla

nco

2001

]

1.2 - 2nd prototype: a large counter

8


40

50

60

70

80

90

100

-80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80

Tim

e re

solu

tio

n (

ps

)

= 50 to 75 ps

Center of the trigger region along the strips (cm)

93%

94%

95%

96%

97%

98%

99%

100%

-80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80

Tim

e e

ffic

ien

cy

Strip A

Strip B

Strips A+B

= 95 to 98 %

Center of the trigger region along the strips (cm)

No degradation when the area/channel was doubled (800 cm2/channel)

[Bla

nco

2001

]

Efficiency and time resolution

1.2 - 2nd prototype: a large counter

Large and yet sharp tim

ing !

9


1.3 Another step: “high-rate” ceramic timing RPCs for CBM@GSI

Ceramic

Stainless Steel

Acrylic Support column

0.3 mmgas gap

020406080

100120140160180200

0 20 40 60 80

Counting Rate (kHz cm-2)

Sigma 2700 2725 2750

2775 2800 2850 3000

Measured with 511keV photons

Tim

e re

solu

tio

n

(p

s)

9% drop/(100kHz/cm2)in 1 gap

[Lopes 2006]

75kHz/cm2

Previously2kHz/cm2

... + rate capability

~1109 cm

10


1.4 - 1st application: shielded tRPCs for HADES@GSI

30

40

50

60

70

80

90

100

10 100 1000RPC rate (Hz/cm2)

Tim

e R

eso

luti

on

(p

s

)

BC7 BL2 BC3 FC-1 BR4 BR2 FC5 FR0

BC-1 FL2 FC7 FR2 FC1 BC1 FL0

Shielded - No cross-talk (>GHz b.w.) - Robust multihit performance

Redundant - Pure gaussian response

11


-1000 -500 0 500 1000 1500 200010

0

101

102

103

Time difference (ps)

Eve

nts/

10ps

Sigma=54 (50) ps

700ps Tails right=0.01%

Events=18339

10-4

10-3

10-2

10-1

Cum

ulat

ive

p.d.

f.

-1000 -500 0 500 1000 1500 200010

0

101

102

103


Eve

nts/

10ps

Sigma=67 (63) ps

700ps Tails right=0.55%

Events=18340

10-4

10-3

10-2

10-1

Cum

ulat

ive

p.d.

f.

Tails: 0.55% above 700 ps Tail cancellation using redundant information

K-

1.4 - 1st application: shielded tRPCs for HADES@GSI

• 6 m2 insta

lled by next spring

• PID capability to se

parate K/ ~ 1 / 1

04

12


1.5 - 2D position sensitive readout

X leftX right

Time signalHV

XY readout plane

Y-strips(on PCB)

RC

passive netw

ork

RC passive network

X-strips(deposited on glass)

out left

out right

10 strips for eachcoordinate

at 4 mm pitch

4 cm

2 mm thick black glass lapped to ~1m flatness

Well carved into the glass (avoid dark currents from the spacer)

300 m thick high glass disk (corners)

metal box (no crosstalk)

Precise construction

(for small and accurate TOF systems)

[Bla

nco

2002

]

Resistive division

13


Eve

nts

/mm

2

Y(m

m)

X (mm)

Position resolution

edges 3 mm

resolution 3 mm FWHM(strips=4mm)

-25 -20 -15 -10 -5 0 5 10 15 20 250

500

1000

1500

Position along X (mm)

Eve

nts/

0.5

mm

-25 -20 -15 -10 -5 0 5 10 15 20 250

500

1000

1500

Position along Y (mm)

Eve

nts/

0.5

mm

4 mm strip pitch

Trigger edge (3 mm)

Chamberedge

-1000 -500 0 500 100010

0

101

102


Eve

nts/

4ps

Sigma=74.0 ps (62 ps)

Center

-1000 -500 0 500 100010

0

101

102


Eve

nts/

4ps

Sigma=76.9 ps (66 ps)

Edge &

Corner

No edge effects (=75%)

[Blanco 2002]

... + localization capability

1.5 - 2D position sensitive readout

14


Charge-sensitive electronics allowing interstrip position interpolation

1.6 Small animal PET - a first prototype

X

Z

16 stacked RPCs

....... .......

32 strips

16 plates

Transaxial

Depth of interaction

2D measurement of the photon interaction point (X,Z)

Aimed at verifying the concept and show the viability of a

sub-millimetric spatial resolution.

15


• Copper (on a PCB) and glass electrodes. • 32 1-mm wide X pickup strips. • 0.3 mm gas gap. • Not optimized for high efficiency (2 mm glass)

Active area 32 x 10 mm2

0.3 mm spacers

ANODE: glass electrode glued on PCB

X

Transaxial coordinate

CATHODE: PCB copper layer

Depth of interaction


16


Intrinsic spatial resolution

Custom-made 22Na source

0.22 Ø x 0.5 mm

LOR = Line of Response, connects the two photon interaction points.

D = Distance between each LOR and the center of the system

Red lines correspond to real data (LORs) acquired with the 22Na source

The system at workThe system at work


17


Image spatial resolution (gaussian fitting)Filtered Back Projection FBP

510 m FWHM 1050 m FWTM

Maximum likelihood-expectation maximization with resolution

modeling (ML-EM)

~310 m FWHM 810 m FWTM

50

100

150

200

-10 -5 -1 1 5 100

10

20

30

40

Distance (mm)

Cou

nts/

100

m50

100

150

200

-10 -5 -1 1 5 10 0

10

20

30

40

Distance (mm)

50

100

150

200

-10 -5 -1 1 5 100

10

20

30

40

Distance (mm)

Cou

nts/

100

m

50

100

150

200

-10 -5 -1 1 5 10 0

10

20

30

40

Distance (mm)

50

100

150

200

-10 -5 -1 1 5 100

10

20

30

40

Distance (mm)

Cou

nts/

100

m50

100

150

200

-10 -5 -1 1 5 10 0

10

20

30

40

Distance (mm)

Proceeding IEEE MIC (2004) M2-177

0.30

0.31

0.32

0.29

50

100

150

200

-10 -5 -1 1 5 100

10

20

30

40

Distance (mm)

Cou

nts/

100

m

50

100

150

200

-10 -5 -1 1 5 10 0

10

20

30

40

Distance (mm)

119mm

[Bla

nco,

IE

EE

MIC

200

4]

• Twice as good as a

ny other PET syste

m

Twice as good as a

ny other PET syste

m

• Approaching the physical limit (~

350

Approaching the physical limit (~

350 m)m)


18


• High granularity: just depending on the pads size• Sub-millimetric position resolution: 0.5 mm or better• State-of-the art time resolution: 50 ps

General look of a demonstration module

Posit

ion-

mea

sure

men

tel

ectro

nics

Tim

e-m

easu

rem

ent

elec

troni

cs

Position measured with patterned

electrode

Time measured on opposing pads

Resistive plates

The pixelized RPC TOF tracker

1.7 Near future (RD51)

19


WG3 Cryogenic detectors + WG4 Simulatios & s/w tools

MPGDs in double phase xenon detectors for rare low energy events

LIP-Coimbra + U.Coimbra/U.Aveiro

1) GEM tests at reduced vapour pressure 2) MHSP tests in 2-phase xenon

WG3 Medical applications + WG7 Common Test Facilities

Study of MPGDs for gamma-ray imaging

LIP-Coimbra

1) GEM/mini-strip readout in double phase xenon 2) Small prototype of liquid xenon gamma-ray imager

2 – GEMs: Commitments within RD51

20


2 - GEMs for high sensitivity experiments

Filipa Balau, Isabel Lopes, Vitaly Chepel*RD51 and Vladimir Solovov,

within the ZEPLIN Dark Matter programme

2.1 – High sensitivity experiments

2.2 – Double phase Xe detectors

2.3 – Our measurements with a GEM

2.4 – Results

21


GOAL: Detection of a few electrons signal (ideally a single e–) in gaseous phase of a LXe double phase detector

Energy of nuclear recoil: 0 to ~50 keV

WIMPWIMPmW ~ 100 GeVEW ~ 50 keV

Ex.2: Coherent neutrino scattering on a nucleus

Ex.1: Direct search for Dark Matter in the form of WIMPs through elastic scattering on Xe nuclei

n

nuclear recoilnuclear recoil

En ~ 50 MeV

nuclear recoilnuclear recoil

2.1 High sensitivity experiments


E1

E2

e-

Xe+

Measuringt ionisation from

recoil tracks

• Total gain of ~104 required

• Stability of GEM operation in saturated gas

(high density, low T, dependence on T fluctuations) ?

• Condensation of the liquid on the GEM ?

• Operation in ultrapure environment ?

2.2 Double phase Xe detectors


Gain = Qext / Q0

Qext – charge reaching collector grid

Q0 – charge collected at lower GEM face (same potential applied to both sides)

Our measurements with a single GEM

Mind ...• Ultrapure xenon• Only clean materials used• Good temperature stabilization

2.2 Double phase Xe detectors

Qext

Q0

– 4 kV

24


Gain as a function of VGEM241Am spectra

5.5 MeV a60 keV g

60 keV g

X-rays

Max gain

19%

T Gmax

Near future plans:- Lower T (... approaching tripple point, -111 C)- MHSP

2.2 Results

• Continuous

Continuous stable operation

stable operation

repeatedly observed over hours

repeatedly observed over hours

• GG maxmax=

150 (=150 ( ~ 2 atm) dependent on T

) dependent on T

[Bal

au e

t al.,

NIM

; in

pres

s]

short overview of lip-coimbra activity in view of 1 - rpcs for time-tagged tracking and

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