Post on 28-Aug-2021
26. June 2012
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PAX Detector Development
| C. Weidemann
26. June 2012 Slide 2
• Requirements
− Future Experiments
− Detector Arrangement
− Simulations
• Design
− Detectors
− Mechanical Design
− Readout Electronics
− Cooling System
• Summary and Outlook
Outline
26. June 2012 Slide 3
Future Experiments With The PAX Detection System
1. Polarizing Antiproton Beams
2. Spin Filtering With Longitudinal Polarization At COSY ()
3. Time Reversal Invariance Test
4. Spin Observables in Breakup Reaction
5. Electric Dipole Moment Polarimetry Tests
26. June 2012 Slide 4
Experience WithSilicon Tracking Telescopes
• Polarimeter for the PAX depolarization
and the spin-filtering experiment at COSY
(Talk: D. Oellers)
• Spectator and vertex detector for ANKE
experiments
A detector that fulfills requirements for the future experiments can be realized
with silicon strip detectors and we can use our experience of more than ten years!
26. June 2012 Slide 5
Aim Of Simulations
• Optimize the system for spin filtering with antiprotons
• Maximization of detector acceptance and measurement performance
• Versatility: - feasability of addititional experiments (pd breakup, TRIC …)
- measurement of all spin observables
• Usage of existing equipment (HERMES detectors, readout electronics)
Detector Arrangement
• Barrel-shaped, φ-symmetric detection system
• 24 double-sided position sensitive silicon strip
sensors in three layers (300 µm, 300 µm, 1500 µm)
• Strip pitch of 0.7 mm results in a vertex
resolution of 1mm
• All spin observables measurable independent
on -dependence ( cos(), cos(2) )
• Application of diagonal scaling methodw = 97 mm
d0 = 80 mm
d1 = 100 mm
d2 = 110 mm
26. June 2012 Slide 6
Detector Arrangement
26. June 2012 Slide 7
Diagonal Scaling
Yieldi
Y0 0,
Y1 0,
Y2 0,
Y3 0,
Y0 1,
Y1 1,
Y2 1,
Y3 1,
Y0 2,
Y1 2,
Y2 2,
Y3 2,
Y0 3,
Y1 3,
Y2 3,
Y3 3,
:=
Combinations of beam and target polarization
See also: (1) H. O. Meyer. Diagonal scaling and the analysis of polarization experiments in nuclearphysics. Phys. Rev. C, 56(4):2074–2079, Oct 1997.
(2) PAX wiki : Spin Filtering at COSY, Simulations
4 q
ua
dra
nts
(de
tecto
rs)
kkiiYX λε=
• Extraction of all flipping and non flipping components possible
• Luminosities
• Detector Efficiencies
∑=k
iki xr
∑=i
ikk xc
reduced matrixreduced matrix
sum of rows:sum of rows:
sum of columns:sum of columns:
iEιιιε Ω=kDn0σ
26. June 2012 Slide 8
Polarizing Antiproton Beams(Talk: P. Lenisa)
• Spin-filtering experiments at AD exploring the systems p bar p, pbard, (pbar He )
(transverse and longitudinal polarization)
• Detector: Measurement of pbar beam polarization using pbarp elastic scattering
• Simulations forpbarp at 43, 120, and 220 MeV kinetic energy including anihilation
processes (G. Macharashvili, M. Tabidze)
• The momentum spectra and thus the energy deposit of secondary particles is
independent on beam energy
Detector setup adequate for all energies
Acceptance for 220MeV
• 26 % of particles hit 1st layer (∆E > 0.2 MeV)
• 23 % of p and 3 % p bar tracks in 2nd layer
• 18.6 % of p and 2.5 % p bar tracks in 3rd layer
• Reconstruction of two tracks for 2 % of events
• Optimal position in z-direction is + 55 mm for the center of the detector
26. June 2012 Slide 9
Spin Filtering With Longitudinal Polarization (COSY)
• Buildup of longitudinal beam polarization due to repeated interaction with a
longitudinally polarized hydrogen target
• Tp 45 - 130 MeV kinetic proton energy
• Detector: Measurement of longitudinal beam polarization using pp elastic scattering
– Measurement during filtering with hydrogen target possible
– Spin correlation coefficient (~ 0.5)
– No background σ
ΩΩ
1 ∙ σ
ΩΩ
1 ∙
C!!
26. June 2012 Slide 10
Time Reversal Invariance Test(Talk: Y. Valdau)
• Experiment concept uses vector polarized p beam on tensor polarized d target
• Lifetime change in dependence on the target polarization
• Tp130 MeV kinetic proton energy
• Detector: Measurement of transverse beam polarization
a) using pd elastic scattering during lifetime measurement
b) using pp elastic scattering after lifetime measurement
− no background
− large spin correlation
coefficients (0.5 – 1.0)
26. June 2012 Slide 11
Simulation Of ppElastic Scattering
• Simulations for various detector configurations for pp elastic scattering
– Teflon cell introduced (10 " 10 mm), 5 µm teflon
– ABS and BRP tube
– 50 µm Kapton covers surface of HERMES detector
• Acceptance: a) 130 MeV
• 14 % of particles hit 1st layer ( ∆E > 0.2 MeV)
• 9.5 % acceptance (tracks in 2nd layer), 8.4 % in 3rd layer
• Reconstruction of two tracks for 5.1 % of events
b) 45 MeV
• 5.9 % of particles hit 1st layer ( ∆E > 0.2 MeV)
• 3.4 % acceptance (tracks in 2nd layer), 2.6 % in 3rd layer
• Reconstruction of two tracks for 2.1 % of events
• Individual shift of layers in z-direction improves efficiency by
< 10%
• Optimal position in z-direction is + 80 mm for the center of thedetector
26. June 2012 Slide 12
Spin Observables In Breakup Reaction
• Study of three nucleon continuum in proton deuteron breakup reactions between
30 an 50 MeV proton beam energy
• Detector: Measurement of vector and tensor analyzing powers and spin
correlation coefficients
• Simulations to test the usability of the detection system, which was developed on
the basis of previous studies
• Stopping of protons and deuterons
is required to clearly identify the reaction
3rd layer of 1.5 mm thickness
is needed to stop particles
up to 30 MeV energy deposit
26. June 2012 Slide 13
PAX Detector Design
(V. Carassiti, F. Evangelisti)
26. June 2012 Slide 14
Detectors - HERMES
• 8 modules available• Suitable for 1st and 2nd layer of detection system• 50 µm polyimide with 5 µm copper traces• Existing Helix front-end has to be removed• Connect new pitch adapter to VA32TA2
Detector HERMES TIGRE300 µm
Coupling AC
Thickness (µm) 300
Active area (mm) 97.3 "97.3
No. of strips 128
Strip pitch (µm) 758
Depl. voltage (V) 50
26. June 2012 Slide 15
Detectors
Detector HERMES TIGRE300 µm
PAX TTT300 µm
PAX TTT 1500 µm
Coupling AC DC DC
Thickness (µm) 300 300#15 1500#50
Active area (mm) 97.3 "97.3 100.42"100.42 100.42"100.42
No. of strips 128 128 128
Strip pitch (µm) 758 760 760
Depl. voltage (V) 50 70 300
HERMES withnew pitch adaptor
PAX TTT
26. June 2012 Slide 16
Layer Design
1st and 2nd layer:
• Ceramic board with
VA32TA2_2 chips
• HERMES detector
• Replace by 300 µm PAX TTT
3rd layer:
• Ceramic board with higher
dynamic range VATA2_2
chips
• 1500 µm PAX TTT
26. June 2012 Slide 17
Layer Design
1st and 2nd layer
3rd layer
26. June 2012 Slide 18
Mechanical Design – 1 Quadrant
26. June 2012 Slide 19
Mechanical Design – 4 Quadrants + Cooling
26. June 2012 Slide 20
Openable Storage Cell
26. June 2012 Slide 21
Mechanical Design – Complete Setup
(V. Carassiti, F. Evangelisti)
26. June 2012 Slide 22
Self-triggering Front-end Chips
90 mm
90 m
m
VA32TA2_2
No. of channels 32
Power dissipation 3mW/channel
Linear range11MeV
(±500fC)
Slow shaper (PT) 2 µs
Fast shaper (PT) 60-120 ns
Minimum trigger
threshold0.04 MeV
Readout frequency 10 MHz
Trigger threshold
range+/- (1.6 - 50) fC
26. June 2012 Slide 23
Self-triggering Front-end Chips
90 mm
90 m
m
VA32TA2_2
No. of channels 32
Power dissipation 3mW/channel
Linear range11MeV
(±500fC)
Slow shaper (PT) 2 µs
Fast shaper (PT) 60-120 ns
Minimum trigger
threshold0.04 MeV
Readout frequency 10 MHz
Trigger threshold
range+/- (1.6 - 50) fC
• Process migration from 0.8 µm to 0.35 µm
− Larger radiation stability
− Lower power consumption (~ 30%)
• Modification of VA32TA2_2 design required
− configuration register memory
(readback possible)
− Individual switch off of channels (0V)
− 32 independent threshold DACs
item FE-Chip-1 FE-Chip-2
Max. input amplitude +/- 500fC
+/- 2500fC
(linear scale-up of
noise)
Trigger threshold range +/- (1.6 - 500) fC +/- (8 - 2500) fC
26. June 2012 Slide 24
Electronic Readout
(S. Merzliakov)
26. June 2012 Slide 25
Cooling System (Design And Tests)
• Cooling and temperature stabilization of detectors and electronics is needed
• Survive 450°C NEG activation and 80°C target chamber bake-out :
Temperature shield
• Conductive cooling will be utilized
• Simulations under way
• Prototype design and tests
Test-bench available with diagnostic system
Cooling
Thermocamera and temperature sensors
26. June 2012 Slide 26
Summary
• Experiment simulations are almost finalized
• General detector arrangement is fixed
• First design of mechanical support and cooling system
• To be done
Final specification and ordering of chips
Finalizing the design of:
– Openable cell
– Mechanics, cooling system, tooling
– Thermo shield
– Electronic readout
– Capton dimensions
– Low / high voltage power supply
Test of cooling system and thermo shield
Test of detectors: 8 HERMES and 12 + 2 PAX TTT
…
26. June 2012 Slide 27
Summary
• Experiment simulations are almost finalized
• General detector arrangement is fixed
• First design of mechanical support and cooling system
• To be done
Final specification and ordering of chips
Finalizing the design of:
– Openable cell
– Mechanics, cooling system, tooling
– Thermo shield
– Electronic readout
– Capton dimensions
– Low / high voltage power supply
Test of cooling system and thermo shield
Test of detectors: 8 HERMES and 12 + 2 PAX TTT
…
26. June 2012 Slide 28
Additional Slides
26. June 2012 Slide 29
Input Parameters
• I = stored protons
•
•
•
227104.61 cmtot
−⋅=σ
213 /108.4 cmatomsdt ⋅=
sdfIrate trev /1950tot =⋅⋅⋅= σ200mm 200mm
dx=dy=10mm
l=100mm
d=10mm
target cell dimensions:
10101 ⋅
Cell wall thickness 30μm
26. June 2012 Slide 30
Event Reconstruction
• 2 protons in coincidence in opposite detectors
(1 proton with 1 hit in each detector layer)
• Energy loss threshold 0.5 MeV
26. June 2012 Slide 31
Event Reconstruction
accepted events
• φ cut -> 59 %
• z cut -> 16.9 % (17.5 %)
• E cut -> 16.9 % (7.3 %)
0
optimal position
200z
beam direction
-200 -10
26. June 2012 Slide 32228,98
Ac
ce
pta
nc
e(%
)
Measurement Time + Acceptance(HERMES detectors)
oz (mm) T (h) Acc
230 12,5 4,78
220 11,0 5,2
210 10,5 5,7
200 9,8 6,2
190 9,4 6,5
180 8,9 6,8
170 8,4 7,1
160 8,3 7,3
150 8,1 7,4
140 8,1 7,4
130 8,1 7,4
120 8,2 7,4
110 8,4 7,2
100 8,9 7,1
70 9,9 6,2
Me
as
ure
me
nt
tim
e (
h)
oz (mm)
T (h)
Acc (%)
Beam storage cell
HERMES
26. June 2012 Slide 33
Event Reconstruction
accepted events
• φ cut -> 59 %
• z cut -> 16.9 % (17.5 %)
• E cut -> 16.9 % (7.3 %)
1 PAX TTT 2 HERMES
1 PAX Layer
• E cut -> 28 %
0
optimal position
200z
beam direction
-200 -40
26. June 2012 Slide 34
Scenario
BRP calibration
1. Injection of polarized proton beam
2. Measure beam polarization at ANKE (pd: D.Oellers)
3. Target polarization measurement at PAX ( pp )
26. June 2012 Slide 35
Design
26. June 2012 Slide 36
Detector Specifications
26. June 2012 Slide 37
0 45 90 135 180 225 270 315 3600.6
0.8
1
1.2
1.4
Pz Qz
Rate4 30 ϕ, poise, Q, ( )
Rate4 30 ϕ, poise, Q−, ( )
Rate4 30 ϕ, poise−, Q, ( )
Rate4 30 ϕ, poise−, Q−, ( )
Rate4 30 ϕ, 0, 0, ( )
ϕ radeg⋅
Longitudinal Polarization (130 MeV)
• smaller total cross section ( )
• large spin correlation coefficients
• same acceptances• no φ-dependence
mb7.25=τοτσ
26. June 2012 Slide 38
Differential Cross Section
26. June 2012 Slide 39
Total Cross Section (mb)
26. June 2012 Slide 40
`
TA-4
TA-3
TA-1
TA-5
TA-2
TA-6
8 VA32TA2 CHIPSPCB6
8 VA32TA2 CHIPS PCB1
HIGHVOLTAGEPOWERSUPPLY
ZEL DAQ SYSTEM CRATE
FAST ADC
OPTO
XILINX CONTROL
OPTO
FAST ADC
TRIGGER
VACUUM PART
FLANGE PART
2 COAX
I2CADC
Optocoupler
VA-TA IN/OUT
LVDS
ORed TA-OUT
R
TRIGGER
TRIGGER
LVDS
LVDS
LVDS
LVDS
LVDS
I2CADC
VA-TA IN/OUT
Optocoupler ORed TA-OUT
RECEIVER 3 POWER
DACS
TRIGGER
OUTPUTAMPLIFIER
FLOATINGLOWVOLTAGEPOWER
SUPPLIES
TRIGGERLOGIC
DIG.BUFFER
I2C BUSMASTER
I2CADC
VA-TA IN/OUT
Optocoupler ORed TA-OUT
RECEIVER 3 POWER
DACS
TRIGGER
OUTPUTAMPLIFIER
DIG.BUFFER
I2CADC
VA-TA IN/OUT
Optocoupler
150 outputs
ORed TA-OUT
RECEIVER 3 POWER
DACS
TRIGGER
OUTPUTAMPLIFIER
2 COAX
DIG.BUFFER
I2CADC
VA-TA IN/OUT
Optocoupler
128 outputs
ORed TA-OUT
RECEIVER 3 POWER
DACS
TRIGGER
OUTPUTAMPLIFIER
DIG.BUFFER
I2CADC
VA-TA IN/OUT
Optocoupler ORed TA-OUT
RECEIVER 3 POWER
DACS
TRIGGER
8 VA32TA2 CHIPS PCB2
OUTPUTAMPLIFIER
FAST ADC
DIG.BUFFER
RECEIVER 3
OPTO
8 A32TA2 CHIPSPCB5
DACS
POWER
ZEL DAQ SYSTEM CRATE
8 8 CHIPSVACUUM PARTPCB3
300 umSi stripdetector
96 outputs
8 CHIPSVACUUM PARTPCB4
2 COAX
XILINX CONTROL
TRIGGER
OPTO
96 outputs
OUTPUTAMPLIFIER
2 COAX
FAST ADC
DIG.BUFFER
1.5 mmSi stripdetector
2 COAXTRIGGER 3
300 um Sistripdetector
OPTO
XILINX CONTROL
2 COAX
150 outputs
128 outputs
FAST ADC
TRIGGER 2
FAST ADC
ZEL DAQ
SYSTEM CRATE
TRIGGER 1
OPTO
26. June 2012 Slide 41
Self-triggering Front-end Chips
VA32TA_2 MATE3
No. Of channels 32 16
Power dissipation 3mW/channel 30 mW/channel
Linear Range11MeV
(±500fC)
50MeV
(± 2220fC)
Slow shaper (PT) 2 µs 1µs and 3µs
Fast shaper (PT) 80 ns 22 ns
Minimum Threshold 0,04 MeV 0,4 MeV
Energy resolution
(Cdet=60pF) 890e- ~ 1530e-
Readout frequency 10 MHz 4 MHz
Time resolution
(E>1.5MeV) ≤0.9ns ≤0.3ns
90 mm
90 m
m
26. June 2012 Slide 42
R- Card
• 1outside vacuum front-end interface per detector side
• decouples front-end chip electronics which is operated at the detector bias voltage
• control signals to read out chips and to set trigger pattern of the R-card are provided via a flat cable
• 2 voltage inputs allow controlling the thresholds and calibration pulse amplitude
• analogue outputs
Inner Vaccum Part
• Detector strips bonded to Kaptonpitch-adaptor
• Connection to the self-triggeringfront-end chips
• Kapton connection to the flange
26. June 2012 Slide 43
• 12 Bit ADCs, up to 10MHz sampling
• One sequencer per detector side
• Hardware common-mode correction
• Hardware zero suppression
Data flow for 2 STTs: event rate ~1000 /s
no zero suppression ~ 5MByte/s
zero suppression ~ 0.1MByte/s
< 50 µs dead-time
ADC + Sequencer Development Completed
26. June 2012 Slide 44
HERMES Detectors
26. June 2012 Slide 45
HERMES Detectors
26. June 2012 Slide 46
Modifications for PAX:
Remove existing Helix front-end
Connect new pitch adapter to VA32TA2
self-triggering front-end chips
fix mechanical constraints / assembly
check Demetrius with atomic hydrogen : cool detectors ?
check each detector with α-source
HERMES Detector
26. June 2012 Slide 47
COSY cooling range
Spin filtering at COSY: Low β-section
Beam lifetimes: Why?
calculated beam polarization after 2 beam lifetimes (Q = 0.8; dt = )213105 −⋅ cm
4000
6000
12000
24000
24000
12000
6000
4000
w3
Folie 47
w3 The next point on the agenda for was to achieve longer beam lifetimes (>10000s), which are needed to reach high polarisations.
You can see the expected polarisation after 2 lifetimes filtering for the transversal and longitudinal case.As you can see the transversal pol. is expected to be very low, whereas for the long. pol. one expects about 25 % for good vacuum cond.
So anyway we have to go for longitudinal polarisation in addition.
The vacuum as major lifetime restricting factor had to be improved beforehand.weidi; 12.03.2010