Status of the FMD

Technical Board, 12 July 2005 Børge Svane Nielsen, NBI 1

Status of the FMD Status of the FMD

Børge Svane Nielsen

Niels Bohr Institute


Inner prototype statusInner prototype statusLeakage current (specs < 3 μA)

Detector capacitance

300 nA

2 nF

Bias voltage 300 V

Bias voltage300 V

Hamamatsu inner sensor prototype:well within specs

→ No changes for production→ Outer sensor design started

IDEAS inner hybrid prototype: VA1_ALICE chips within specs Minor changes to hybrid details→ 2nd prototype to be delivered mid Aug.

Prototype module (sandwich) status: m.i.p. particles seen (500 MeV e-) Noise level now as expected→ Further beam tests 25-26 July→ 2nd prototype mid Aug.

Readout electronics status: → ongoing


First inner type moduleFirst inner type module

Gluing of first ”sandwich” module and bonding at CERN

500 MeV e- beam test at Aarhus, DK

FMD module

e- beam

hybridsensor pitchadaptor


Aarhus beam testAarhus beam test

Problems discovered: - wrong read-out timing - strip noise too high

Cou

nt

Expected m.i.p.signal

m.i.p.(wrong timing

shifted peak down)

New beam test scheduled 25 July

Recorded energy on single Si strip. Most e- beam outside strip acceptance.


Prototype noise testsPrototype noise tests

Tests to eliminate noise:- bonded ”flat” module (to reduce hybrid-sensor capacitance): no change- various grounding schemes: no change- add noise filter to HV bias: noise reduced to expected value (6-700 ENC)- noise level now independent of further shielding/grounding/power supply/...

Flat module with external HV filter Sandwich module with HV filter on hybrid


Prototype noise testsPrototype noise tests

Short strips(580 ENC)

Long strips(730 ENC)

badchannelson hybrid

unbondedstrips


Further prototype testingFurther prototype testingLab test with sandwich and IDEAS readout

... and Digitizer+RCU readout

Good progress with prototype Digitizer andUSB version of RCUNext:- complete Digitizer+RCU tests- repeat beam tests- build second sandwich with new hybrid RCU Digitizer


FMD internal mechanicsFMD internal mechanics

Support plate:Al honeycomb (?)combined with cooling

Hybrid

Si sensor

space for support feet

Digitizer board


A

A

Cut view A-A

1514

740

SPD cone

53 FMD3

3rd cone

Tensioning device80mm x 12mm

Top corner:Z = 727.5R = 323.4

Bottom corner:Z = 679.4R = 258.4

752

628R

172

R42

R15

4R

284

Wheel centerZ = 469.0R = 60.0

20

134

309

28

R49

2.5

668

45°

R38

4

36

85

26.9

R35

R39

6 (?

)

R40

0

R49

5

3020

45

84985

180

Ring of the temporary supportWings of the temporary support

V0-C

Overall dimensions(Flavio Tosello) RB26


Beam pipe and FMD3 support cone, RB26 side

Beam pipe and FMD3 support cone, RB26 side

Model was modified for integration tests: 4 supports + 4 wheels + wire tensioners

1:1 model usedfor integration tests

Carbon fibre cone designed (NBI+N.Golubev):


Integration test FMD3Integration test FMD3


Finite element calculations of beam pipe support

Finite element calculations of beam pipe support

Displacements below 20 mStresses below 7 MPa(safety factor 20)

Input dataweights: cone 4.82 kg detectors 3kg each (2 detectors)

Load on each string (4 strings): 500 N

But, realistic load is below: 50 N

Carbon fibre structure


A

A

1510

740

1020

R41

5

R54

0

Patch Panel + AirDuct envelope

R49

2.5

752

R15

4R

284

R17

0

shadow of supports of SPD optical connectors

SPD cone

ITS cone

SDD pre-manifold

800 (?)

R28

0

R (

?)

53

R (

?)

834

R17

2R

42

11.6

°

13.1

°

(856?)

RB24

Ring of the temporary supportWings of the temporary support

3020

R40

0

R49

585

180

FMD+pipe support

668

648

78

780

142

Tensioning device26

Overall dimensions(Flavio Tosello)


Preliminary sketch of FMD+beampipe support on RB24(F. Tosello)

60

114

134

1010

142

ITS SIDE

26

ITS

SID

E

60

R492.5

R390

R334

R324

60

10

10

FMD2 supportFMD2 support


FMD2 supportFMD2 supportPreliminary design of FMD+beampipe support on RB24


Integration test FMD2Integration test FMD2

For integration test, a ’quick and heavy’ version of the FMD2 was used.Important dimensions were OK, materials too heavy, FMD protection missing.


FMD3 mechanicsFMD3 mechanics

Support plate

Digitizer boardInternal mechanics asfor FMD2 and FMD3.

Missing a ’frame’ or ’box’to attach to V0.

Needs further interaction with integration team.


ConclusionsConclusions

Inner type sensor (Hamamatsu) and hybrid (IDEAS) work to expectations

→ design of outer sensors started→ ready to order all inner sensors now→ 2nd hybrid prototype in August, small changes

Readout electronics tests with Digitizer and RCU ongoing FMD3 cone: mechanical drawings ready to bring to carbon fibre industry FMD2 support: detailed design to start in August FMD1 box and support: details to be worked out in collaboration with integration team

Status of the FMD

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