Progress Report of ECAL Work in Beijing

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Progress Report of ECAL Work in Beijing  
Hesheng Chen Institute
of High Energy Physics, CAS Oct.
27-31, 2003, AMS TIM, CERN

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Outlines

• ECAL SQ Tests in Beijing
• FEM Model Correlation after SQ Tests
• Weight Saving of ECAL Structure
• Prepare for ECAL flight Module Manufacture
• Future study on data of ECAL Beam Test

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1. ECAL SQ Tests in Beijing

• Jan. 2003 the final assembly of ECAL prototype
  was done in IHEP, and the ECAL Space
  Qualification Tests (SQT) was completed in BISEE
  according to the relevant documents and specific
  conductions from NASA/LM.
• 4 engineers from LM and Mr. Franck Cadoux
  from LAPP joined with us during the SQT.
• ECAL SQT was successful.

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Final assembly of ECAL is ready in IHEP
workshop in Jan. 9, 2003.
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ECAL in Vibration Tests and
Sine Burst along horizontal direction, in BISEE.
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ECAL was in Vibration Tests
and Sine Burst along vertical direction, in
BISEE
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2. FEM Model Correlation after SQ Tests

• After ECAL SQ Tests, we started the FEM
  analysis for model correlation following the
  suggestion from LM engineers and the agreement in
  ECAL group. The work was cooperated with Yi Wang
  at CERN.
• See the talk by Dr. Yi Wang.
• The FEM Model Correlation have been
  accepted by LM.

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From Martin, Trent mailtotrent.martin_at_lmco.com
Sent Monday, September 22, 2003 346 PM To Yi
Wang Cc Bollweg, Ken Balas, Chittur Tutt,
Chris franco.cervelli_at_pi.infn.it Jean-Pierre
Vialle Chen Hesheng Franck
Cadoux Subject RE Progress on ECAL FEM
Correlation     This looks much better than what
you had before. It is acceptable to use this
model for the Safety Review and the weight
savings analysis. Please do not make any changes
to the brackets for your weight savings
efforts.   Please document your results in a
formal report and forward to us prior to the end
of October to support the Phase II safety review
data package.   Thanks, Trent
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3. Weight Saving for ECAL Structure

• Based on this new FEM Correlation Model, and
• the detailed analysis about the stresses, margin
  of
• safety, natural frequencies, displacements, also
  check
• bolts M.S., fail and safe analysis, etc. We
  discussed with the mechanical engineers and
  manufacture engineers for the detail technical
  procedures for ECAL manufacture, now
• we suggest the following weight saving plan

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Basic ECAL Mechanical Structure
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Main Parts in the structure
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Original saving (before SQT) only by cut 2 raw
square holes on 2 Side Panels (4 raw PMTs)
3.2kg
Fasteners change increased 0.8 kg Thus the total
weight is 73.6kg.
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Our New Weight Saving
1) cutting vertical slots on side panels
Mass reduction 0.1kgx20.1kgx20.4kg
Before
After
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2) Decreasing the depth of PMT holes from 38mm to
18mm
Mass reduction 1.4kg x 2 1.6 kg x 2 6.0kg

38mm
18mm
After
Before
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3) Cutting horizontal grooves on side panels
Mass reduction 0.18 kg x 4 0.7 kg
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4) Decreasing plate thickness due to material
changed to AL-7050
Mass reduction 0.1 kg x 4 0.4 kg
18mm
20mm
After
Before
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5) Cutting triangle holes on side walls
Mass reduction 0.07kgx4 0.28 kg
Before
After
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6) Cutting rectangular holes on back wall
Mass reduction 0.1kg x 4 0.4kg
Before
After
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Mass increasing due to additional anti-loose caps
1 piece 24g Quantity 16 Sub 384 g
1 piece 14g Quantity 8 Sub 112 g
Total 0.5 k g
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Mass reduction summary
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• The weight of ECAL Structure will be reduced
  from
• Before SQT 76 kg 3.2 kg 0.8kg 73.6 kg
  This reduction 7-7.5 kg.
• the expected final weight 66.1 - 66.6 kg

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4. Prepare for ECAL flight Module Manufacture

• 45 months are expected to produce Flight
  Module
• Before the production started, we have to
• 1) Agreement in ECAL group in the weight
  reduction approval by LM
• To check interfaces with panecake and PMT support
  parameters of all dimensions
• The new engineering drawings based on the new
  weight saving plan frozen parameters

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4) fixed manufacture schedule of Flight
Module 5) order materials - AL. 7075 and
relevant fasteners (help from LM) - Spring
Foam A274 (help from Pisa) 6) Send Pancake with
the assembly plate to Beijing We are
happy to have an engineering meeting beforehand
in Beijing for the discussion of technical
interface.
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5. Future study of ECAL prototype Beam Test data

• Improve e/p separation
• Titled impact
• Effective area
• Preliminary !

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e/p separation Update

• electron preselection
• in addition to from number of hits and energy
  per hit cut, shower start point is required to be
  inside the first superlayer to select electrons
  in the electron run
• energy mixed electrons were used to train
• against proton with 120 GeV

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Neural network cut 0.97 50 GeV electron
efficiency 90 120 GeV proton efficiency
0.45 ECAL alone
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At 120GeV proton efficiency 0.45 , electron
with different energies stay at around 90 with
ECAL alone normal impact in the middle
of ECAL.
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Normal impact vs tilted impact
As for the energy resolution difference is
small. but 10 Degree is the best
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Normal impact vs tilted impact
The difference in angular resolution, is
small. 10 degree is also the best.
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Normal impact vs tilted impacte/p separation
Trained against 120GeV proton with normal impact
in middle. For 120GeV electron, 20 degree is the
best.
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Effective area energy measurement
Energy mean value and resolution of electron
impact on the last PMT is deteriorated Dead PMT
causes more severe problem.
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Effective area angle measurement

• For electrons with normal impact on the
• last PMT on edge
• mean value deviate
• from impact angle by more than one sigma
• resolution is not deteriorated too much.

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Effective area e/p separation
xy
In compare with 120GeVproton normal impact
in middle, electron efficiency is not
deteriorated on edge and even on corner.
y5
With proton efficiency 0.45
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Thanks
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ECAL test configuration in Z direction
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ECAL test configuration in X and Y direction
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Summary

• For normal impact, the effective area is
• the region with
• 34PMTs X 34PMTs
• To know the effective area changes with
• impact angle, more (runs) and better (without
  dead PMT) data is needed.