AMS02 ECAL

1
AMS-02 ECAL Status of construction and
electronics
Marco Incagli INFN-Pisa July 21, 2004
2
0 - Introduction on ECAL
g
e, p ?

• An Electromagnetic CALorimeter measures the
  energy deposited by charged and neutral
  particles, in particular photons and e
• This allows for
• Very good positron/proton discrimination
• Detection of non-interacting photons (75)
• Trigger information on photons and on e

3
Dark Matter searches in positrons
Sensitivity after one year data taking Precise
data extended to higher energies will be provided
by AMS
m? ? 336 GeV
m? ? 130.3 GeV
e
Based on the work of E.A. Balts et al. 99
4
Dark matter searches in positrons

• To detect the signal at the 10-2 value a
  suppression factor of 106 is needed in the e/p
  ratio
• The TRD provides a factor 102
• The ECAL standalone provides a factor 103
• Including the energy-momentum match, a further
  factor 10 is gained

5
ECAL in trigger (backsplash recovery)
Including ECAL
Trigger Efficiency on positrons
Without ECAL (low efficiency is due to Anti
Coindidence Counters vetoing on positron
backsplash)
Positron energy (GeV)
6
ECAL structure
p?
e?

• Sampling calorimeter with lead foils and
  scintillating fibers
• 9 superlayers with alternating x and y readout
• Total thickness is 166mm, corresponding to 17.2
  X0
• Total weight 638 kg

Lead foil (1mm)
Fibers (?1mm)
z
particle direction
18.5mm
y
x
7
Lead foils - fibers technique

• The same technique has been used by the KLOE
  experiment at DAFNE ee- machine (Frascati, Rome)
• KLOE is a high energy physics experiment which
  aims to the measurement of CP violating
  parameters in the Kaon system

8
KLOE electromagnetic calorimeter
superconducting coil
Pb - Sc.Fibres - Matrix ltrgt 5 g/cm3 ltX0gt
1.6 cm sampl. frac.15 (m.i.p.) Measured
performances sE /E 5.7 /?E(GeV) s t 54 ps
/?E (GeV) ? 50 ps
ECAL modules
Responsable of KLOE ECAL F. Cervelli - INFN Pisa
9
Supporting structure and readout of AMS ECAL

• The active part is inserted in a supporting
  structure which connects ECAL to USS ? see the
  talk of Wang Yi
• Light is readout with PMTs connected to fibers
  through light guides

y
x
z
66 cm
18.5 mm
10
Light collection system

• The light is finally readout by a multianode
  Photo Multiplier Tube (PMT) which converts it
  into an electrical signal
• PMTs have 4 active anodes 9?9 mm2
• Total of 324 PMTs , 1296 readout cells

11
1 - Tests of ECAL prototype

• A full scale prototype has been built in
  2001-2002
• Tests performed on it
• Test with electrons/protons at CERN for
  performances
• Space Qualification Tests in Beijing
• Mission Success Tests in Terni (Italy)

12
1.1 - Tests with CERN beam
A full scale prototype has been tested at CERN in
2002 with electrons of energy 3-180 GeV and
protons of energy 120 GeV
Incoming beam
13
Performances
Longitudinal profile
50 GeV e-
?/E 2.73?0.10
50 GeV e-
Energy resolution
14
Angular resolution

• Fit of shower CoG on each layer, excluding the
  first two

??68 (degrees)
50 GeV
Beam energy (GeV)
15
Test Beam results on e/p separation

• e/p separation using neural net
• Protons misidentified as positrons leave half
  of their energy in ECAL (?E/p0.5)
• ee 0.95 , ep 0.0052
• R ee/ep 22.7 ? 103

50GeV electrons 120GeV protons
95 of e-
5.2 of p
16
1.2 - Space Qualification test
Test required by NASA, performed in Beijing,
followed and certified by LMSO
Progress Report of ECAL Work in Beijing  
Presented by Hesheng
Chen Institute of High Energy Physics, CAS Oct.
27-31, 2003, AMS TIM, CERN
17
Final assembly of ECAL is ready in IHEP
workshop in Jan. 9, 2003.
18
ECAL in Vibration Tests and
Sine Burst along horizontal direction, in BISEE.
19
ECAL was in Vibration Tests
and Sine Burst along vertical direction, in
BISEE
20
Sine-Sweep Test

Typical Curve of Sine-sweep
Test was successful ? see talk of Wang Yi
21
1.3 - Mission Succes test at Terni

• Test to study the effect on optical contact and
  readout of vibrations due to launch and docking
  on ISS

Presentation from Catherine Adloff - LAPP Annecy
TIM january, 20 2004
SERMS
22
Participants
ECAL in horizontal position
23
Z Vibrations
Random Z axis
24
Sequence of the Tests
3.1 gRMS
3.1 gRMS
3.2 gRMS
2.3 gRMS
First period Nov. 17 Nov. 21 2003
Second period Dec. 3 Dec 5 2003
25
Typical Accelerometer Answers
Sine sweep X axis (before and after Random)
Winglet resonance frequency
Accelerometer C 36 Radiator winglet
First ECAL mode
89 Hz
Accelerometer C 25 Back panel centre
The results of the Beijing tests (frequency
modes) are confirmed
26
PMT results a Closer Look
Relative variation after Z vibration
No PMTs damaged and no optical contacts lost
during the test Stability of readout 5 in
worst conditions (Z vibration)
Variation ()
PMT channel
27
2 - Status of ECAL construction
28
2.1 - laying down of fibers-lead-glue
29
2.2 - pressing at the needed thickness
30
2.3 - machining top and bottom surfaces
31
Thickness (Dz) after machining
Dz 18.4?0.1 mm
32
2.4 - milling of lateral sides
33
After milling
34
After polishing
35
Lead Plates Quality Check
Measurements Dimensions and weight of each
plate Effective Thickness computed as
weight/(surface x density) Width of the millled
edge using microscope A database is created with
all the lead layers characteristics
36
LAST superlayer in order to gain weight, the
last foil is an Al foil of 1.1 mm thickness
machined with 1mm grooves
37
Grooves in Al foil
38
Total weight of active part (pancake)
11 superlayers have been glued and machined Best
9 will be piled up, glued and prepared for
shipment in august-september 2004
Total weight 487.8 kg 1 kg(glue) 488.8
kg (expected weight was 489 kg)
39
Next milestones of the pancake

• End construction in september 2004
• Shipment to Beijing in october for assembly with
  supporting structure
• Shipment to Annecy in december for equipment with
  PMTs
• ECAL equipped by end of July 2005

40
3 - ECAL electronics general view
ECAL crate
ECAL Intermediate Board (EIB)
EPSFE
PMTFEE
ETRG
JINF
EDR
HV
LV
ANALOG (on ECAL)
POWER SUPPLY
41
3.1 - electronics on ECAL
Responsability of LAPP-Annecy ? See talk of
Glenn Cougoulat
EIB
EFEE
42
3.2 - ECAL crate (2 crates on experiment)
EDR data reduction board ETRG trigger
board EPSFE Power Supply for the Front End
(slow control capabilities)
EPSFE
ETRG
JINF
EDR
1
2
3
1
2
3
4
5
6
1
1
Responsability of Pisa Standard AMS
43
Low Voltage - redundancy - slow control
28 A
EDR
DC/DC
3.3 H
SSF
FEI
3.3 H
1/0
HV BRICK
3.8/-2.8 H
LeCroy7..0
28A
HL
CDP
to FE
ELR
3.3 H
CL
CDP
LeCroy2-4-6
3.3 H
JINF-A
SSF
FEI
HV
3.3 C
0/1
1/1 or 0/0 both off
3.3 C
JINF-B
HL
EPSFE
LeCroy3-5-7
ELR
3.3 C
3.3 H
on if powered
28 B
3.8/-2.8 C
LeCroy0
SSF
1/0
3.3 C
3.8/-2.8 H
PW to FE (thr. EDR BKP)
DC/DC
3.8/-2.8 C
SSF
LeCroy1
0/1
28 B
3.3 C
1/1 or 0/0 both off
on if powered
PDB
CL
44
EDR CARD
First version of EDR card ready and currently
under test In order to test it a EIB emulator
and a mini-backplane have been built
EDR
minibackplane
EIB emulator
Experts from Pisa and Annecy are currently at
CERN to write a first version of the sequencer
code with V. Koutzenko
45
ETRG PCB status
The PCB design is ready at 90 PCB design ready
before august holidays board built in september
2004 Very complex design with 6 routing planes
and 4 powerground planes
46
Next milestones for electronics in Pisa

• Contact CAEN and start definition of backplane in
  september 2004
• Start work on EPSFE in october 2004
• Both boards ready and tested by end of march 2005
  ? start production

47
3 - HV power supply the BRICK

• Final position of brick modules (fixed in january
  2004)

Bricks (inside Ecrate in old scheme)
Ecrates
OLD SCHEME
NEW SCHEME
48
Brick electronics new controller

• Due to different brick location, and to a
  modification in the controller firmware, a new
  controller version has been ordered to CAEN on
  may 12, 2004
• CAEN expects to deliver the mounted new
  controller by october, 2004

49
Brick mechanics connection to USS

• CGS is in charge of the design of
• new mechanical structure which holds the brick,
  replacing the old VME crate,
• mechanical connection between brick and USS
• A preliminary version was shown by M. Molina at
  this TIM

50
Bricks mechanics internals II

• Pisa workshop is building the parts for ECAL

51
Bricks electronics - test of prototype in Pisa
52
First results linearity
Different regulators
Linearity
53
First results stability
HV Brick Calibration _ hot section
8 bits used to set HV in the range 500-1000
V Expected stability 500V / 28 2V In final
version we may have an additional bit ? expected
stability 1V
2.5
2
1.5
1
0.5
(HV output) wrt average
0
-0.5
-1
-1.5
D
-2
-2.5
-3
400
500
600
700
800
900
1000
HV set
54
Brick thermal tests

• Brick stability tested cycling the temperature
  between -30o and 60o (enviromental temperature)

60o
25o
-30o
4 hours
55
Results of brick thermal tests

• Brick temperature and voltage were sampled every
  20 seconds
• After a stabilization period of ?10 minutes, the
  HV readout is stable within 1 Volt

Voltage read out (3 channels equipped with
passive resistors)
Temperature of brick case (a sensor was attached
to the Al)
56
Milestones for brick

• Continue testing prototype
• As soon as new controller arrives, test new
  firmware at CERN
• If everything works ? QM ready in november 2004
• Internal mechanics ready november 2004
• Start mass production in november 2004

57
Conclusions

• Active part of detector ready in september 2004
• ECAL structure assembled in Beijing
  october-november 2004
• ECAL at LAPP on december 2004 for instrumentation
  ? ready end of July 2005
• ECAL detector electronics end of 2005
• Test beam planned beginning of 2006 (as soon as
  beam will be available at CERN)