Report from TRD Workshop Trento, March 3-4

1
Report from TRD WorkshopTrento, March 3-4
Hannes Wessels, Univ. Muenster

• results from test beam analyses
• TRproduction and X-ray absorption measurements
• gas properties
• recent advances of the read out electronics
• progress on DCS and services
• super-module design and integration
• status of chamber production
• software status
• planning

2
Test Beam Setup at T10
measurements w/o magnetic field
measurements with magnetic field
3
Test Beam Setup

• Setup with 4 small chambers and a prototype of
  the largest TRD chamber (1200x1600mm2) (DC5)

4
Cleanliness of e/p Separation
V. Yurevich, A. Andronic
with coincidences of the two Cherenkov counters -gt
contamination of e in p and vice versa smaller
than 1/1000
5
Performance of Various Radiators
A. Andronic
-gt no significant momentum dependence of
p-rejection
6
Charge Distributions
A. Andronic
-gt distributions well described at fixed
momenta -gt possible effect of Bremsstrahlung
visible
7
e/p Performance by Layer
A. Andronic
-gt performance of individual layers almost
identical -gt slight improvement with depth
(Bremsstrahlung) -gt slightly worse performance
for large prototype (S/N)
8
Independence of Efficiencies
A. Andronic
-gt efficiencies for pion identification of
the different layers factorize -gt layer 5
slightly worse due to different S/N
9
Influence of Material in Front of TRD
A. Andronic
-gt performance of the different layers with
(triangles) and w/o (circles) material in
front of the radiator -gt 8mm Al -gt X/X09 -gt
10cm in front of DC1 -gt small impact at very
low momenta
10
Influence of Material on Resolution
O. Busch
-gt B0 -gt no effect on resolution for
pions -gt small effect for e
11
Influence of Material on Resolution
O. Busch
-gt B0, 0.28, 0.42, 0.56 T -gt no change in
resolution for pions -gt electrons somewhat
affected as depth increases because
Bremsstrahlung is produced before dipole
12
Position and Angular Resolution
O. Busch
-gt no deterioration of resolution in magnetic
field -gt slight decrease in angular
resolution for large angles -gt space charge
effects
13
Lorentz Angle Measurements
O. Busch
-gt good agreement of data and simulation
to the level that CO2 contents variation,
drift velocity, and alignment are
understood
14
TR Measurements
O. Busch
-gt beam is deflected from TR photon by B-field
15
Energy and Multiplicity of TR Photons
O. Busch
-gt TR energy spectrum well understood -gt
measured multiplicity lower than simulated
0.85
16
X-Ray Absorption Measurements
R. Schicker, T. Lehmann
Setup at MPI Heidelberg
17
Measurements of Radiator Materials
R. Schicker, T. Lehmann
-gt actual radiator less than 50 transparency
for ETR lt 6keV
18
Gas Property Measurements
G. Tsiledakis, C. Garabatos

• using mini-drift chamber
• establish procedure of known mixtures (Ar/CO2,
  Ar/CH4) then test Xe-based mixtures (Xe/CO2,
  Xe/CH4)

19
Drift velocity measurements small DC
90Sr (b-source)
G. Tsiledakis, C. Garabatos
Slit1 Slit2
l2.25 cm
drift electrode
Ud-1 kV -1.3 -1.6
-3.7
d3.15 cm
pads
drift region
along pads
gas-mixture
pads A K
across pads
Scintillator (trigger)
phototube
Ua1.5 kV
EUd/d (kV/cm) /p(bar) ul/Dt (cm/ms)
t1 t2 Dtt2-t1
20
PH (mV/0.74)
Drift time (ms)
pad number
21
Ar-CO2 (23) gas mixture
G. Tsiledakis, C. Garabatos

• Why 23 CO2?
• New calibration of the flow meters
• Test of the method shows agreement
• with GARFIELD
• All next measurements across pads

Drift velocity (cm/ms)
across pads
along pads
GARFIELD
E (kV/cm)
22
Ar-CH4 (10) gas mixture
G. Tsiledakis, C. Garabatos

• First run
• Use of a premixed gas mixture
• shows a discrepancy with GARFIELD
• and MIT .
• Second run
• Re-mixing on our own after a new
• calibration.
• Confirms MIT measurements,
• GARFIELD, our calibration and our
• method.

Drift velocity (cm/ms)
2nd GSI measurements
1st GSI measurements
MIT measurements
GARFIELD
E (kV/cm)
23
Xe-CH4 (10) gas mixture
G. Tsiledakis, C. Garabatos
Drift velocity (cm/ms)

• Disagreement with Garfield
• and measured data!

GSI
Christophorou
MIT
GARFIELD
E (kV/cm)
24
Xe-CO2 (15.4) gas mixture
G. Tsiledakis, C. Garabatos

• Disagreement with Garfield

Drift velocity (cm/ms)
GSI
GARFIELD
E (kV/cm)
25
Xe-CO2 (20.5) gas mixture
G. Tsiledakis, C. Garabatos

• Disagreement with Garfield

-gt need certainty about gas composition -gt
multiple scattering in Xe larger? -gt
existing data insufficient -gt need
measurements with controlled nitrogen
contamination
Drift velocity (cm/ms)
GSI
GARFIELD
E (kV/cm)
26
Gas system status
C. Garabatos, GSI

• stability of pressure
• N2 separation
• membrane test

27
Stability of detector pressure
C. Garabatos, GSI
28
Concerns about cryogenics method
C. Garabatos, GSI

• For on-line regeneration
• Long regeneration times several weeks
• Safety lack of NL2 would result in loss of gas
  and perhaps loss of the plant
• Need extra Xe volumes
• Composition gets modified
• Consider, for the filling, the use of membranes
  (Fill with CO2, not with N2)
• During running periods, leaks must be kept to a
  minimum
• Use cryogenics only at end-of-run is desirable

29
Semi permeable membrane test(from ATLAS TRT)
C. Garabatos, GSI
30
Performance expectationsfor one TRD filling
C. Garabatos, GSI
1 membrane
2 membranes
Pressure (bar) Xe lost (m3) Time (days) Xe lost (m3) Time (days)
1 2 6.5 1.3 6.5
2 2 4.5 1.0 4.5
3 2 3.5 0.9 3.5
4 2 2.8 0.8 2.8
31
Summary
C. Garabatos, GSI

• N2 removal feasible at end-of-run
• Also possible on-line, but long and tedious
• membranes look attractive for the filling
  (with CO2)
• last crucial test (gas distribution) are being
  carried out right now
• PRR after PRR of ATLAS TRT
• No document à la TPC foreseen

32
The leak question
C. Garabatos, GSI
33
Electronics Progress

• PASA
• TRAP ADC, digital filter, tracklet
  pre-processor, tracklet processor, controls
• read out board
• DCS
• grounding
• services

34
PASA - Chip
H.K. Soltveit, V. Catanescu
Parameter
No. channels 183
Noise (ENC) 702 e (25pF) 20e/pF
Conversion Gain 12.5 mV/fC
Shaping time about 120 ns
Non-linearity lt 0.16
Power consumption 13.5 mW/ch
output variations with T, Vdda lt0.23 (20 deg) lt0.03 (200mV)
-gt fully differential design -gt essentially
ready for submission (end of April) -gt
final simulations in conjunction with ADC
ongoing -gt potential problem with ground loop
under investigation
35
Measured Crosstalk as Function of Pad-Pad
Capacitance
H.K. Soltveit, V. Catanescu, I. Rusanov
crosstalk in
max. input signal
36
ADC
D. Muthers, R. Tielert, KL

• 10bit, 10MHz cyclic converter designed by
  University of Kaiserslautern
• current design needs 0.1mm2 and 6mW
• needs additional input buffer for decoupling from
  PASA
• no longer providing reference voltages to PASA
• potential ground loop because input cells also
  need analog 3.3V
• full design with 21 channels will be part of the
  next submission (May)

37
ADC Chip Performance
V. Angelov, HD

• ADC tested with all CPUs running and IRQs
  turned on
• ADC power derived from digital power and turned
  on from idle state (unrealistic worst case)
• observed drift less than 1 bit
• rms deviation from fit to pure sine wave lt 0.9
  bit

38
Tracklet Preprocessor
Digital FILter
V. Angelov, HD
64 timebins deep
DFIL
Event
Buffer
ADC
Non- Lin
Tail- canc
Cross- talk
Offs
Gain
Q
DFIL
Condition Check
ADC
hit
Event
Buffer
Position
Para
-
CPU0
Calc
meter
COG
Q
DFIL
Condition Check
ADC
LUT
Calc
hit
)
hits
Event
Buffer
Position
Para
-
CPU1
Calc
meter
COG
LUT
Calc
Unit (max. 4
181
channels
FIT Register File and tracklet selection
Position
Para
-
CPU2
Calc
meter
COG
Select
LUT
Calc
Q
DFIL
Condition Check
ADC
Hit
hit
Position
Para
-
Event
Buffer
CPU3
Calc
meter
COG
LUT
Calc
Q
DFIL
Condition Check
ADC
hit
FIT register file is for the CPUs a readonly
register file
Event
Buffer
DFIL
Event
Buffer
ADC
39
Pedestal correction (offset)
V. Angelov, HD
This filter stage corrects for some offset in
PASA and ADC and adds a programmable offset to
the corrected value
40
Tail cancellation filter
V. Angelov, HD
This filter stage corrects for the gas ion tail.
It is a IIR filter. The tail can be
approximated by a sum of two exponentials. The
parameters are selected with the requirements
output pulse has nearly Gaussian shape and no
undershoot.
41
Summary of Test Results
V. Angelov, HD

• What has been tested
• Serial Configuration, most of the configuration
  registers in all blocks, connected to the Global
  Bus
• Clock gating, Global State Machine
• The large LUTs (non-linearity, position), Event
  Buffers
• CPUs with Register Files and Interrupt
  controllers
• DFF Instruction and Quad Port Data Memories, Quad
  Port Full Custom Instruction and Data Memories
• Local Buses
• parallel Network outputs with the delay units
• Acquisition in the event buffers, digital
  filters
• ADCs
• PLL, Clock and Pretrigger distribution outputs
• parallel Network inputs
• What is still not tested Real acquisition mode

42
Summary of Test Results
V. Angelov, HD

• many functional bugs - none of them makes the
  chip unusable. For final version they are not
  acceptable
• -gt simulate !
• CPUs operate at clocks up to 70-80 MHz, instead
  of 120MHz. Some parts operate reliably up to
  120MHz (SCSN, GSM).
• -gt timing analysis !
• The ADC parameters (noise and some bad effects at
  large amplitudes) are not influenced by switching
  the CPUs on

43
Read Out Boards
I. Rusanov, HD
-gt one board for all layers
44
MCM Boards
I. Rusanov, HD
-gt designed as BGA -gt direct chip-to-chip
bonding -gt version with PASA, ALTRO, and
TRAP chip still needs to be evaluated
45
Noise Measurements on Large Prototype
I. Rusanov, M. Ciobanu, T. Mahmoud
-gt frequency response of PASA on the bench
46
Noise Measurements on Large Prototype
I. Rusanov, M. Ciobanu, T. Mahmoud
-gt typical response without good
shielding/grounding
47
Noise Measurements on Large Prototype
I. Rusanov, M. Ciobanu, T. Mahmoud
-gt response with current shielding/grounding
concept
48
TRD DCS Card
M. Stockmeier, V.Petracek, D. Gottschalk

• one card per chamber
• DIMM connector
• contains TTC
• FPGA running Linux
• Ethernet network
• multiplexed ADC inputs
• for monitoring T,V etc.
• needs about 5W
• DCS board ---gt KIP
• software ---gt Worms

49
Supermodule
ALICE-TRD
Length 7m Weight 300kg Fully equipped
1,2 to
ALICE-TRD Workshop, 3.3. 4.3.03, Trento Bernd
Windelband, Uni Heidelberg
50
New chamber segmentation
ALICE-TRD

• 12 different chamber types
• Largest ROC 1,45m x 1,2m
• Only 2 differnt types per layer

ALICE-TRD Workshop, 3.3. 4.3.03, Trento Bernd
Windelband, Uni Heidelberg
51
Supermodule
ALICE-TRD
TOF
TRD SM
Rail-roller system
ALICE-TRD Workshop, 3.3. 4.3.03, Trento Bernd
Windelband, Uni Heidelberg
52
Supermodule2/5 Prototype
ALICE-TRD
ALICE-TRD Workshop, 3.3. 4.3.03, Trento Bernd
Windelband, Uni Heidelberg
53
Supermoduleservice space
ALICE-TRD
-gt space for services very tight -gt 4mm
reduction of chamber width on both sides
ALICE-TRD Workshop, 3.3. 4.3.03, Trento Bernd
Windelband, Uni Heidelberg
54
SupermoduleRail System
ALICE-TRD
To avoid additional load from the space frame
Fixed rail
movable rail
ALICE-TRD Workshop, 3.3. 4.3.03, Trento Bernd
Windelband, Uni Heidelberg
55
Supermodule into LDS
ALICE-TRD

• Lifting device

• supermodule

• Handling and transport frame

ALICE-TRD Workshop, 3.3. 4.3.03, Trento Bernd
Windelband, Uni Heidelberg
56
Lifting device(LDS)
ALICE-TRD
ALICE-TRD Workshop, 3.3. 4.3.03, Trento Bernd
Windelband, Uni Heidelberg
57
Readout Chambers
H. Appelshaeuser, D. Emschermann, T. Mahmoud
Padplane/Read out unit

• dimensions frozen
• new pad plane backing
• currently evaluating with two large chambers
• assembly procedure
• tooling
• test procedure
• leak tightness
• gain uniformity
• tolerances
• PRR April,30
• ready for production in Heidelberg starting in May

Drift volume
Side frame
Radiator
58
Assembly of TRD Chambers
- clean room - 3D measurement system - precision
mounting jigs
59
Chamber Radiator
60
Radiator Production in Münster
D. Bucher, W. Verhoeven

• all fiber material ordered
• material cut for largest modules
• backing on order from AIK and Fischer
• 3 glass tables ready
• can work on 2 radiators/table
• tools in preparation
• done for first radiators
• assembly of 6 radiators in parallel
• neglecting man power
• 2 radiators ready / day

61
Deformations of Wire Grids after Wiring
H. Appelshaeuser
-gt well within acceptable tolerances
62
Wire Spacing After Wiring
H. Appelshaeuser
-gt without (!) combs for wire alignment
63
Wire Tension Measurements
D. Emschermann
cathode
anode
-gt deformation due to cathode as expected no
effect on anode
64
Pad Planes
D. Emschermann

• designs for all chambers almost finished
• alternating tilted pads design
• will have identical footprint on readout side
• foresee NO connector on pad plane, instead use
  Z-bonding tape for direct connection of cable to
  read out board

65
Software Developments

• framework well advanced
• needs implementation/parameterization of actual
  TR response for PID simulation
• needs implementation of services
• trigger simulation ongoing along with hardware
  implementation scheme
• NEED backward compatibility of AliROOT

66
General Planning

• would like to initiate integration meeting with
  TOF and technical coordination
• will aim for re-baselining of the detector after
  PRR of chambers and submission of digital chip
  (catch up during production)