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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, [email protected], [email protected]
Asic1
e-mode
h-mode
PulsePeriod@200us, [email protected], [email protected]
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: [email protected] 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.