Status of production at LNF

E. Dane, C. Forti, D. Pinci, A. Sarti – LHCb Muon CERN 25-may-04

31-Jan10-Feb20-Feb1-Mar

11-Mar21-Mar31-Mar10-Apr20-Apr30-Apr10-May20-May30-May

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Chamber

Clo

sing

dat

e

Monday 24-may: closed chamber 30. Will close 2 more this week.

Chamber differential closing rate

0.0

1.0

2.0

3.0

4.0

5.0

6.0

6 8 10 12 14 16 18 20 22 24 26 28 30 32

Chamber number

Rat

e (c

h/w

eek)

5/(work days required) 7/(all days required)

Chamber integral closing rate

Average production rate (ch.14-23)

0.90

1.10

1.30

1.50

1.70

1.90

2.10

2.30

13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Chamber number

cham

bers

/wee

k

5/(work days required) 7/(all days required)

Panel differential winding rate

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

29-Jan 13-Feb 28-Feb 14-Mar 29-Mar 13-Apr 28-Apr 13-May 28-May

pan

els/

wee

k

7/all days 5/work days

Panel differential winding rate

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

14-Jan 29-Jan 13-Feb 28-Feb 14-Mar 29-Mar 13-Apr 28-Apr 13-May 28-May

Dif

fere

ntia

l win

ding

rat

e (p

an/w

eek)

N*5/(work-days required) N*7(all days required)

Panel average winding rate

2.00

3.00

4.00

5.00

6.00

7.00

8.00

15-Jan 30-Jan 14-Feb 29-Feb 15-Mar 30-Mar 14-Apr 29-Apr 14-May 29-May

winding date

aver

age

win

din

g ra

te (

pan

/wee

k) N*5/work-days from 23-jan N*7/all days from 23-jan

Reasons of delay

For some time the company producing the cathodes did not send the FR4 foils with cathode pads to the Internormal. In 2 periods: 7-16 Apr. and 27 Apr. 5-May we winded only ground panels (layers L1 and L3) and could not close chambers.

HV-bars drawing current: from 15-Apr we found panels drawingcurrent during the HV test. The possible cause was a set of HV-barswith much humidity in their plastic bag. They were cured by heating(under infrared lights) and, if needed, removing the conformal coatingand cleaning them.Then we started a systematic check of all HV-bars.

We found a panel with tested HV-bars drawing current:we investigated the wire under the microscope but did not find a systematic difference between samples from good vs. bad panels.

Observation of wire from one panel drawing current

We found a panel with tested HV-bars drawing current: we investigated the wire under the microscope but did not understand much.

gold removed

Observation of last 6 spools received

All samples seem OK

Average tension (± sigma) 113 panels of chambers 6-35

55.0

60.0

65.0

70.0

75.0

80.0

85.0

0 20 40 60 80 100 120A

vera

ge t

ensi

on (

g)Wire tensionIn panels with smaller <T> : wires have beenglued at smaller tempe-rature and/or wireshave been cut too soon ( after ~12 hrs)

We reached the

goal < 2 g

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

0 20 40 60 80 100 120

Wired panel (C6L1=1)

Sigm

a of

ten

sion

(g)

We have increased thepower of heating lights and fresh gas was put in the clean room conditioning system

Fraction of substituted wires

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 20 40 60 80 100

Wired Panel (C6L1=1)

Inte

gral

Fra

ctio

n (

per

mil)

113 panels of chambers 6-35

< 1 per mil

HV test

0

10

20

30

40

50

60

70

20 25 30 35 40 45 50

Humidity (%)

Las

t cu

rren

t (n

A)

100 panels of chambers 6-30

0

100

200

300

400

500

600

700

0 2 4 6 8 10 12 14 16 18 20 22 24 26

ChamberI(

nA

)

A B C D

Uniformity test: currents in gaps and

bi-gaps

B higher

The uniformity betweendifferent gaps of a samechamber and of differentchambers is improvingcompared to cham 1-10

In chamber 22, gap B draws ~ 50% more current320 vs. 220 nA

0

100

200

300

400

500

600

700

0 2 4 6 8 10 12 14 16 18 20 22 24 26

Chamber

I(n

A)

AB CD

C>>D

CD OK

Currents in chamber 24

Currents in chamber 22

Effect of brass bars ch 22 (C,D) C

D

Chamber 22 gaps C,D

The 3 brass bars putbelow the chamberas support,produce a visibleeffect on gap currents

N. of goodgaps in each chamber (1-25)

>95% in range(0.8 – 1.25) G0

14 chambers rejectedless than 4 gaps OK

>90% in range(0.8 – 1.25) G0

8 chambers rejectedless than 4 gaps OK

0

1

2

3

4

5

0 2 4 6 8 10 12 14 16 18 20 22 24 26

ChamberN

. of

good

gap

s

0

1

2

3

4

5

0 2 4 6 8 10 12 14 16 18 20 22 24 26

Chamber

N. o

f go

od g

aps

N. of goodbi-gaps in each chamber (1-25)

>95% in range(0.8 – 1.25) G0

4 chambers rejected:1,2,4,5less than 2 bigaps OK

>90% in range(0.8 – 1.25) G0

2 chambers rejected:4 and 5less than 2 bigaps OK

0

1

2

3

0 2 4 6 8 10 12 14 16 18 20 22 24 26

ChamberN

. of

good

bi-

gap

s

0

1

2

3

0 2 4 6 8 10 12 14 16 18 20 22 24 26

Chamber

N. o

f go

od b

i-ga

ps

End of M3R3 production (52+2 chambers)

End M3R3: 30-jul / 16-aug Start M5R3 in September

23-May-04

22-Jun-04

22-Jul-04

21-Aug-04

8-Feb 23-Feb 9-Mar 24-Mar 8-Apr 23-Apr 8-May 23-May

Chamber closing date

En

d o

f M

3R3

pro

du

ctio

n

2 ch/w 2.5 ch/w

End of M3R3 production (216 wired panels=54 chambers)

2-Jul

12-Jul

22-Jul

1-Aug

11-Aug

21-Aug

31-Aug

10-Sep

14-Jan 3-Feb 23-Feb 14-Mar 3-Apr 23-Apr 13-May 2-Jun

En

d o

f 20

8 p

anel

s w

ind

ing

6 panels/week 8 panels/week

End M3R3 calculated from winding rate: 30-jul / 21-aug

LNF production schedule (updated 24-may-04, ch. 30)

(52+2) M3R3 + 52 M5R3 + 52 M1R4 + 125 M1R3 = 283

0

50

100

150

200

250

300

1-Sep-03

1-Dec-03

1-Mar-04

31-May-04

30-Aug-04

29-Nov-04

28-Feb-05

30-May-05

29-Aug-05

28-Nov-05

27-Feb-06

29-May-06

28-Aug-06

Cha

mbe

rs

Plan Actual M3-M5R3 2/w M1 3/w

Holidays: 2 weeks (Christmas) + 1w Easter + 4w August = 7wEnd prod. = Plan: 15-mar-06 Extrapolation: 26-jun-06

Conclusions

Wire tension:

1. reached the goal < 2 g

2. <T> smaller in 4 panels temperature in winding machine increased.

Wire pitch: never found a wire out of specs (<1.9 or >2.1 mm)

Other procedures are stable and OK: wire soldering machine, panel

preparation, WTM, HV test, chamber assembly.

We are investigating the cause of some panels drawing current even if

HV-bars. May be the wire is dirty ? It gets dirty during soldering procedure ?

Chambers produced up to now: one chamber (N.3) leaks.

Uniformity test: 4 chambers (1,2,4,5) with bi-gaps area < 95% in range

(0.8 – 1.25) G0 we will build 2-4 more M3R3 chambers.

Cosmic ray stand, nearly ready, will allow soon to switch on 6 chambers

together for a ~2 weeks conditioning

HV test

0

10

20

30

40

50

60

70

0 20 40 60 80 100 120

Panel (C6L1=1)

Las

t I

(nA

)

100 panels of chambers 6-30

HV and ground connections check

A wire pad (13 wires x 2 mm pitch) disconnected from HV

A 2.75 cm pad disconnected from ground

Altough the beam flux has a 15 cm diameter, the system can give very precise information

Chamber 12

Gap C

Gap D

... while the gain of the Bi-Gap CD is rather flat.

A bent panel between gaps C and D provides this situation: the gain in the gap C and D not uniform...

What about efficiency, time resolution and cluster size?

... to be investigated with test beam or cosmic rays...

Bi-gap CD