RPCs new schedule & QC results

July 18 2002 S. Patricelli ATLAS TMB 1

RPCs new schedule & QC results

Schedule Gas Volume production schedule Global RPC schedule

QC results Gas Volume production - gluing Gas Volume production - oiling Gas Volume production - currents Production database

Outline


Gas Volumes production plan at GT(Standard Units)


Gas Volumes Production details(Standard Units)


Global schedule

The Gas Volume production sequence still has some flexibility, but not much due to time necessary for material procurement.

BOS production before BOL - Easy BOS production before BMS - Very difficult

The Global schedule for RPC Units production has to take into account the production status of all other components.


Production status - All parts


Readout panel production

Concern at present is for the preparation of readout panels (i.e. mounting of F.E. boards on strip panels).

Main reason for the delay is last delivery of Front End boards from Microtel. This was the first large delivery of F.E. boards for BML-D Units now under production.

However: this is also the most time consuming task in the production chain of RPCs.


Global RPC schedule

Special Units not included in this schedule.We must first reach “cruise speed” in the production of Standard Units.


Gas Volume QC - Gluing

The original idea (PRR) for spacer gluing QC was to prepare an external sample and measure the maximum stressing force before breaking. This test was found to be not the optimal solution for gluing QC.

During its production at GT BaBar prepared a machine which allows to measure, on closed gaps, if any spacer is not glued (push test).

RPC is laid on a straight table and gas flow is allowed up to a fixed pressure (5 mb).

A row of spacers is “touched” by a series of 660 gr. loads and P is measured continuously.

If one of the spacers is not able to stand that pressure a clear jump in pressure is seen.



Filling up Localizing the spacer inside the row.

4.9

5

5.1

5.2

5.3

5.4

0 10 20 30 40 50 60 70

atlas_1741.push

P (

mB

ar)

Time

5.05

5.1

5.15

5.2

5.25

5.3

5.35

5.4

0 5 10 15 20 25

atlas_1741.spush.row 12 and 13

P (

mB

ar)

Time

row 13

row 12

1

2

3

4

5

6

0 5 10 15 20 25 30 35 40

mB

ar

Time

Localizing rows of spacers with problems.



We started the push test QC on our gas volumes after the “gluing crisis” and the introduction of the “washing machine”.

Every day, before starting production, GT prepares some samples to verify glue polymerization.

Of all gas volumes produced in a day one undergoes the push test. If one gas volume has more than one spacer not well glued, the

full production of that day undergoes the push test. Gas Volumes with more than one spacers not well glued are

discarded.

Production from 28/5 to 13/6 8/3672 = 0,2 % spacers not well glued1/62 gas volume discarded (5 spacers)

Production from 14/6 up to nowawaiting test at GT Future production push test done weekly


Gas Volume QC - Oiling

The facility now at GT allows the simultaneous oiling of at least 40 gas volumes.

When this operation is done:

Collect a sample of the (output) oil which has been used Fill up one gas volume to high pressure (max 80 mb). If

gas volume not broken (as it happens almost in all cases) the chamber is mechanically opened for visual inspection.

Cut one or more pieces (10 x 10 cm2) of oiled backelite

Items 1 & 3 are sent to the Dept. of Chemistry of Torino University


Gas Volume QC - Oiling - IR analysis

The oil is first polymerized in thin films on inert support (to check the polymerization time) and then IR analyzed to detect if any contaminant is present.

3446

2927

2854

2690

1743

1628

1458

1167

1099

978

725

.05

.1

.15

.2

.25

.3

.35

.4

3500 3000 2500 2000 1500 1000 500

Absorbance / Wavenumber (cm-1)Paged Y-Zoom CURSOR

File # 9 = ATLAS11 6/13/02 12:44 PM Res=None

olio 3 polimerizzato

Only absorption peaks due to linseed oil present



The sample of oiled backelite is IR analyzed using a micro ATR (Attenuated Total Reflectance) technique to detect any impurity or sign of oil degradation.

3276

2925

2854

1739

1541

1458 13

19

1155 11

03

982

893

808

0

.1

.2

.3

3500 3000 2500 2000 1500 1000

Absorbance / Wavenumber (cm-1)Paged Y-Zoom CURSOR

File # 2 = ATLAS07 6/4/02 3:01 PM Res=None

Atlas #4 P-1102 L

Only absorption peaks due to linseed and bakelite present

Backelite



For each set on analysis we receive a written report (.doc) which is inserted in the production database.

Gas Volumes oiled up to may 16th have been certified by this test.

For Gas Volumes produced after this date we are waiting for results.


Gas Volume QC - Currents

For chambers produced with “new” (2002) bakelite we decided to add a new step in the QC control chain before Gas Volumes are assembled in Units.

Before oiling, chambers are flushed in pure Argon, the HV is raised till current reaches 30 A ( ~ 2.5 kV) and the chamber is monitored for three days. Chambers with anomalous current drift are discarded (0/290 up to now).

After oiling chambers are flushed with ATLAS gas mixture (without SF6), HV is raised up to 9 kV (@20 °C) while recording the V-I characteristic.


Gas Volume QC - Currents

Total Currents

0

1

2

3

4

5

6

7

8

9

10

0 2 4 6 8 10

Applied voltage (kV)

Cu

rre

nt

(mic

roA

)

Not accepted (1/44) Under observation (3/43) T = 32 °C

Exp component of the current

0

1

2

3

4

5

6

7,9 8 8,1 8,2 8,3 8,4 8,5 8,6 8,7

Voltage (kV)

Cu

rre

nt

(mic

roA

)


Production Database (1)

Status of RPC production is reported in the Production Database. All parts are identified by bar-code.

Bakelite plates: Details on all bakelite plates produced (Lecce at PanPla) Data from QC-1 (preparation) form (General Tecnica)

Gas Volumes: Data from QC-2 (assembly) form (General Tecnica) Push test results (Napoli at General Tecnica) Current test results (Roma2 at General Tecnica - work in

progress) Data from QC-3 (oiling) form (General Tecnica) IR analysis results (Torino University)



Readout panels: Results of Burn-in and bench test of F.E. boards (separate DB in

Roma2) Mounting of F.E. boards on strip panels (Roma2)

Support panels: Production data of support panels (Protvino)

RPC Unit assembly: Details of all parts which are in a Unit (Lecce)



The Production database is available on the web via a user interface at http://pcatlas2.na.infn.it (link from the RPC ATLAS page).

Warning: Data are not all up to date. Still need some sensibilization of the production sites to transfer

data in due time. Some problems with 2001 production data which we are trying to

recover.

QC results are accessible with queries via the user interface. Some are already implemented. Others are now being developed.


User Interface (1)

Query result to trace back all components in a Unit.


User Interface (2)

Query result to verify Gas Volume production status.


Conclusion

Gas Volume for ATLAS production schedule is still compatible with ATLAS schedule.

Main concern at the moment is the schedule for Readout Panel production.

Time for special chambers still to be “allocated” in the schedule. This will be done only after “cruise speed” for Standard production is reached.

QC in Gas Volume production with new technique is under control for gluing, oiling and currents.

Production Database needs some update for 2001 production (mostly bakelite).

All QC results as described are in the D.B. Need to implement more queries (web interface) to extract statistical information.

Documents

RPCs new schedule & QC results