construction of the silicon tracker for the r3b experiment

Construction of the silicon tracker for the R3Bexperiment.

M.Borri (STFC)on behalf of the teams at

Daresbury Laboratory, Edinburgh and Liverpool Universities.

Outline:

• FAIR and R3B.

• Overview of Si tracker.

• Mechanics, sensors, ASIC, DAQ.

• Electrical and in-beam tests.

• Conclusion.

FAIR.

• Facilities for Antiproton and IonResearch (FAIR).

• It is an expansion of GSI.

• Secondary beams of highlyunstable nuclei (up to 1 GeV/u).

• Produced by primary heavy ionsbeam hitting production target.

• Separated in-flight within 100’s ofns: Super FRS.

• High-energy branch for secondarybeams up to Bρmax of 20 Tm.

R3B.

• Kinematically complete measurementsof reactions with high-energy radioactivebeams.

• Unprecedented high efficiency,acceptance, and resolution.

• Reactions with relativistic radioactivebeam (R3B).

• Emphasis on nuclear structure anddynamics.

• Located in high-energy branch ofSuper-FRS.

Silicon tracker.

• Precise tracking and vertexing,as well as energy andmultiplicity measurements.

• Conical shape.

• Detect light charged particles(like protons) from the targetregion.

• Double-sided micro-strip siliconsensors wire bonded to acustom made ASIC.

• 30 detectors:6 in inner layer;12 in each of the 2 identicalouter layers.

• Total sensitive area∼5600 cm2.

• 912 ASICs equivalent to116,736 front-end channels.

• Each outer layer: 384 ASICs(49152 chs);Inner layer: 144 ASICs(18432chs).

• Operated in vacuum.

Mechanics.

• Support structure made of Al.

• Cooling system based on Cu (pipes andblocks) and H2O+Glycol (coolant).

• New Cu-blocks: better alignment; goodthermal contact.

• ASIC temperature range: 0-70oC.

• Vacuum chamber made of Al.

• Total volume of ∼0.148m3.

• ∼2mm wall: low material budget (2.2% of X0).

• Reached target vacuum: 1e-5 mbar.

Sensor.

Sensor specificationsType double sided

Bulk doping n-typeBulk thickness 300 µm [ABC] 100 µm [BD]

Strip pitch 50 µmStrip width 38 µmStrip length variable

Strip stereo angle 16.2o

Isolation implant p-sprayGuard rings 9 floating

I-leak per strip 3.25 nA/cm [<100 nA]Strip capacitance 2.3 pF/cm [<80 pF]

• BD detector for inner layer.

• ABC detector for outer layers.

• Starting production from ABC detectors.

• Sensor successfully assembled to carbon-fibre frame.

• It has I-leak<8µA@60V (op.voltage).

ASIC.

• Readout based on a daisy chainsequence.

• Four ASICs are connected in a chain.

• They are not adjacent to each other.

• Rate in each ASIC proportional to theassociated strip length.

• Designed at STFC RutherfordAppleton Lab.

• The R3B ASIC is intended for readingout signals from the N and P strips.

• The chip provides three informations:

1. strip number.

2. energy deposit.

3. time of the hit.

ASIC specifications

Size 13x6 mm2

CMOS process AMS 0.35 µmPower consumption < 1.5 W/ASICChannels per chip 128

Data rate < 5 kHz/channelEnergy range 0-50 MeVTime stamp 200 MHz

ASIC testing.

• Tests performed on bare ASICs.

• Front-end characterization performed withinternal pulse.

• Comparing ASIC with its specifications.

• Particular focus on : threshold tuning;front-end linearity; signal sampling; ADC toenergy.

Channel [a.u.]

0 20 40 60 80 100 120

Pu

lse-

mea

n [

AD

C]

2180

2200

2220

2240

2260

2280

2300PulsePeriod@200us, PulseAmpl@0.5V, PeakTime@8.0us

Asic1

e-mode

h-mode

PulsePeriod@200us, PulseAmpl@0.5V, PeakTime@8.0us

DAQ.

• Control ASICs: set registers,distribute clock.

• Synchronize tracker withother sub-detector systems.

• Transfer data to experimentDAQ (NDAQ).

• MIDAS software: wellestablished in UK nuclearcommunity.

• Total of 3 uTCA crates: 10FEE cards in each crate.

• 1 FEE card for eachdetector.

• Current cable hasmeasurable x-talk, exploringother types.

Detector testing.

Channel[a.u.]

0 256 512 768 1024 1280 1536 1792 2048

Std

.Dev

.[A

DC

]

0

1

2

3

4

5

6

7

8

9

10Pulse-std.dev. Vs Channel

N-side

sµPeak-time 1.0

sµPeak-time 4.0

sµPeak-time 7.0

Pulse-std.dev. Vs Channel

Channel[a.u.]

0 256 512 768 1024 1280 1536 1792 2048

Std

.Dev

.[A

DC

]

0

1

2

3

4

5

6

7

8

9

10Pulse-std.dev. Vs Channel

P-side

sµPeak-time 1.0

sµPeak-time 4.0

sµPeak-time 7.0

Pulse-std.dev. Vs Channel

• Test-pulse injected in each individualchannel.

• Input capacitance ∝ strip length.

• I leak ∝ strip length.

• Higher noise for longer strips.

• More uniform and lower noise with highshaping time.

N.B. N-side has a broken daisy chain.

In-beam test @ GSI.

Burkhard Kolb, Phone +49-6159-71 2667, E-Mail: beamtime@gsi.de 10/14/2014 3:48:00 PM

2 / 2014 October 2014 Schedule as of 14-Okt-2014

Week 40 Week 41 Week 42 Week 43 Week 44

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

U207, Backe/Block, 48Ca (EZR), Y7 SHIPTRAP

U259, Düllmann, 48Ca, X8 U207, Backe/Block, 48Ca, Y7 SHIPTRAP UB04,

Groening/Spiller, U, UNILAC

U259, Düllmann, 48Ca, X8 U282, Ortner/Blazevic, Ca, 3.6MeV/u, pµA, Single Shot

Experiment, 5Hz, Z6

UBIO, Scholz, Ca, X6

U259, Düllmann, 48Ca, X8

U000, Barth/Hollinger, p (MUCIS), UNILAC

S438 Simon, Ca, block sharing, HTC S401Heuser/Kis, Ca, block sharing, HAD

S000,

Spiller, N,

S000, Spiller, U, SIS S411,

Plaß/Purushothaman, U, FRS

S438, Taeib,Simon, U,

Nach HTC,

S411, Plaß/Purushothaman, U,

FRS

S000, Spiller, U, SIS

S438 Simon, Ca, block sharing, HTC S401Heuser/Kis, Ca, block sharing, HAD

S000,

Spiller, N,

S000, Spiller, U, SIS

SMAT, Trautmann, 300-400 MeV/u, Sm, HTA

S401Heuser/Kis, Ca, block sharing, HAD

S000,

Spiller, N,

SMAT, Trautmann, U, FRS

S417, Nociforo/Simon, U, 300-1000

S411, Plaß/Purushothaman, U,

FRS

S438, Taeib,Simon, U,

HTC, FRS

S411, Plaß/Purushothaman, U,

FRS

E082, Litvinov, Sm, FRS-ESR, ESR E000, Steck, U, soweit möglich,

ESR E098/E116, Bräuning-Demian, U, ESR, HTA

• GOAL: study reactions produced by a Ca48 beam hitting a CH2 target.

• MEAN: detect correlations of signals produced by particles in CALIFA and Si-tracker.

• OUTCOME: we acquired two data sets which could enable finding correlations.

• BUT: To achieve this goal we had to adopt several work around to overcome severaldifficulties.

• The scientific goal allowed us to test our detector system in terms of:

1. building.

2. mounting.

3. operating.

4. taking data.

5. analysing data.

In-beam test @ GSI.• 3 detectors to GSI.

• Det101 and Det104 are in front of CALIFA petals.

• Det103 does not have a CALIFA petal behind it.

• Only operated a fraction of Det101.

• Main problems: data corruption, data repetition, highleakage current.

• Problems caused by:cabling (ongoing),firmware (fixed),detector assembly (ongoing).

• Data analysis started.

Exp.S438, cave CRun290 3777

Target Thickness Beam type Beam energyCH2 4.98mm Ca48 550MeV/u

ADC vs TS: Pside (side1)

TS[s]

1048.5 1048.55 1048.6 1048.65 1048.7 1048.75 1048.8

310×

[A

DC

]

500

1000

1500

2000

2500

3000

3500

4000

spill ~25s ADC vs TS: Pside (side1)

Conclusion.

• The R3B silicon tracker is under construction.

• Mechanics, sensors, ASICs and DAQ are in an advanced stage.

• Tests allowed for an improvement of the setup.