Report on special „LEAD-MEETING“ at CERN on May-18 2004

1

PbReport on special „LEAD-MEETING“

at CERN on May-18 2004

1. Compatibility issues

• mechanical hardness needed for BAM• chemical compatibility with emulsions

irrespective of packaging option (vacuum or mechanical)

2. Placement of priorities and urgencies

• further test w/ emulsions ??• prototype mass production ??• Immediate financial commitment to low-activity

lead acquisition ??

3. Must overcome deadlock situation

2

Pb

0

5

10

15

20

25

30

35

40

0 5 10 15 20 25 30 35 40

Strain [%]

Str

es

s [

MP

a]

Pb

Pb-Ca alloy

The two extremes: Pb & Pb-Ca

Breaking point

tearing (fluidity region)

elasticity region of Pb-Ca

3

Pb Tensile tests on different Pb alloys(as was provided by JLGoslar)

Samples Rm (MPa) Rp0.2 (MPa) Elongation (%)

Pb (99.99%)

Pb+Cu0.05

ASM values (Chemical Lead

99.90 +%Pb)

17.4 6.9 35

14.1 5.7 20

16-19 6-8 30-60

Pb+Ag0.015+Al0.02 16.1 5.4 31

Pb+Ag0.015+Sn0.01 16.3 5.4 23

Pb+Ca (0.08 %)

ASM values (Pb-0.07Ca)

33.3 19.8 26.5

36-39 30-45

did probably not

contain Al

4

PbThe most common lead alloys

1. Pb-As (not tested)2. Pb-Ca (NO!!)3. Pb-Ag (too soft ??)4. Pb-Sn (deemed NO!!, but good surface

qualities)5. Pb-Sb (not tested)

1. Pb-Ca-Sn (NO !!)2. Pb-Ag-Sn (deemed NO!!, but good surface

qualities)3. Pb-Sb-Sn (deemed NO !!)4. Pb-Sb-Sn-As (not tested, but also contains Sn!!)

binary alloys

ternary alloys

Further options

Pb-Cu (too soft)Pb-Al(0.02)-Ag(0.02) (potentially OK)

5

Pb

Following is a recap of tests done

(already known from talk of DF in JAPAN)this information is only useful if Ca-Pb is still viable

BUTin view of the problems it is wise not to

further entertain a Pb-Ca solution for the moment

Switch to page 18

6

Pb

As received samples:

-Presence of Ca, below 1% at, in XPS (detection limit ~ 0.1% at in ~ 2 nm depth), 80% at of C

-Ca is below C (X-ray Photoemission Spectroscopy as a function of emission angle)

NGL cleaned samples (detergent for cleaning of UHV parts)

-less Ca , not detected in XPS , sometimes in SIMS (5-10 times more sensitive, but not easily quantitative)

- oxide thickness not well reproduced from one cleaning run to the other

Surface analysis of Pb

7

Pb

NGL cleaned samples

-Ca increases on NGL surface stored 2 weeks in ultra-high vacuum, oxide thickness 1 nm: surface segregation at room T ?

- Ca does not increase on surface stored 2 weeks in air (XPS),

oxide thickness 2nm at the end

Thermal oxidation of NGL cleaned sample (4 hours – 150ºC in air):

- Ca diffusion toward the surface, through oxide (5 nm) .

Ca in Pb: Storage

8

Pb

0

10

20

30

40

50

60

70

80

as-receivedsamples

after NGLtreatment

after 2 weeks invacuum

after 2 weeksunder air exposure

NGL + H2SO4

C

O

Pb

Ca

Si

S

0

1

2

3

4

5

6

7

as-receivedsamples

after NGLtreatment

after 2 weeks in vacuum

after 2 weeks in air

NGL + H2SO4

XPS detection

limit

Ele

men

t “c

once

ntra

tion”

(at

.%),

XP

S

Ca in Pb as-received, NGL cleaned, storage

9

PbAnalysis on plates exposed to film-emulsion

Stored at 30° C in air , ~ 1 month and then analyzed:

-F pollution (F on top) on all emulsion exposed faces (not on back)-Ca almost below detection limit (XPS) on all plates, both faces;

detected in SIMS as trace (no quantitative evaluation)-No differences between samples in oxidation state or

oxide thickness

-No correlation with “fog” seen in the developed emulsions-The emulsion contains Ca, F, Na, S

Pb NGL cleaned

Pb as received

Pb pure (CERN store)

vacuum packaging

mechanical pressure packaging

10

PbXPS analysis of the emulsion

(results in atomic %)

0

10

20

30

40

50

emulsion

Ele

me

nt

"co

nce

ntr

atio

n"

(at.

%)

COFNCaNaSPb

11

Pb

0

5

10

15

20

25

30

35

40

45

50

after NGLtreatment

after 2 weeks invacuum

after 2 weeksunder airexposure

after 4 hours at150ºC

Ele

men

t "c

once

ntra

tion"

(at

.%) C

O

Pb

Ca

Si

Ca in Pb as a function of storage method

12

Pb

0

10

20

30

40

50

60

70

Pb + Ca NGL #1.C.1 vacuum

30ºC

Pb + Ca NGL #2.C.1 pressure

30ºC

Pb + Ca AR #1.B.1 vacuum

30ºC

Pb + Ca AR #2.B.1 pressure

30ºC

Pb AR # 1.A.1vacuum 30ºC

Pb AR # 2.A.1pressure 30ºC

Ele

me

nt

"co

nce

ntr

atio

n"

(at.

%)

C

O

Pb

Ca

F

Sides exposed to emulsion

XPS results: side exposed to emulsion

13

PbHardening of the PbCa by

precipitation of the Pb3Ca compound

14

Pb

Pb-Ca alloysFour transformations are observed for Pb-Ca alloys TTT diagrams

Pb-0.058wt.%Ca

Pb-0.09wt.%Ca

New representation of the hardening processes of lead alloys by transformation-time-temperature (TTT) diagrams J.R Hilger, L. Bouirden, 1995.

20 ˚C

15

Pb

Pb-Ca-Sn Alloys

Pb-0.11wt.%Ca-xwt.%Snx = 0.24

x = 0.44

x = 0.64

x = 1.09


16

Pb The mechanical properties of Pb-Ca-Sn alloys depend mainly on the ratio of tin content to calcium content. (Lakshmi, Manders, Rice, 1997 ; Maitre, Bourgignon, 2001).

%Sn

17

PbEffect of Ag

Pb-0.08wt.%Ca-1.11wt.%Sn-0.0027wt.%Ag

Pb-0.11wt.%Ca-1.09wt.%Sn


18

Pb

18• Need to know more about details of „prototype“ mass

production of lead• Need to inject knowledge about mechanical properties

into BAM• Need to know more about quality control at level of

production (flatness, surface, precision of cutting, etc)

• All the above has not been possible with a low quantity of lead (so far less than 1t)

• Even mixing the alloy (Pb-Ag-Al) is not possible with low quantities

• So far we have been addressing each problem individually thereby loosing sight of the complexity of the whole project

19

Pb Placement of priorities and urgenciesProposal:

1) JLGoslar will over the next month acquire up to about 100t of low-radioactivity lead and stock it. This will be done in such a way as to not upset the price of lead on the market

2) The activity level will be monitored (either thru PTB-Braunschweig or thru TARI-project of DF) for each charge.

3) Münster will set aside the funds for the lead acquisition (~100k€)4) This repository of lead will be used to run several „prototype mass

productions“, trying to achieve all necessary specifications (surface flatness, cutting precision, cleaniness, etc).

5) Several lead alloys can be tested under real conditions (collaboration will define composition --- JLGoslar will produce within 4 – 6 weeks)

6) An engineering study will be performed for on-line surface cleaning, using the cleaning prescription devised by CERN TS-Group (with NGL-detergent). The objective is to design an appropriate on-line cleaning facility for further mass production. FINANCING to be defined!!

7) Hardness of lead plates will be assessed and tested by BAM-factory

8) The chemical compatibility tests can continue in parallel without loosing time.

20

Pb

Advantages

1) Always clean lead available for chem-tests

2) Immediate feed-back possible (either from BAM, BMS, or emulsion-lab)

3) Always clearly defined conditions

4) Used lead can be recycled (in part)

5) JLGoslar is willing to cooperate

21

Pb

Cleaning recipe from CERN TSG

22

Pb

Dexcel SL 80 (Biosane) Room temperature - 24H treatment by immersion

Dexcel SL 80 (Biosane) Room temperature - 24H treatment by immersion + Detergent NGL 17-40 Temperature 60C - 10g/l - 5 H treatment by immersion Detergent NGL 17-40 Temperature 60C - 15g/L - 2 H treatment by immersion – ultrasonic agitation

UNSATISFACTORY Oily aspect : Visual control

Perchloréthylène Vapour phase 120C – 30 minutes

UNSATISFACTORY Oily aspect : Visual control

SATISFACTORY Visual control

SATISFACTORY Visual control Confirmed by XPS (83% C as received, 26% C after cleaning) (EDMS:https://edms.cern.ch/document/440094/2)

1. Tests to assess the cleaning efficiency (Pb/Ca)

Lead cleaning

TS – MME / CEM C. CHARVET – L. FERREIRA – S. ILIE 18th may 2004

OPERA PROJECT: LEAD ALLOYS CLEANING Received alloys: Pb/Ca, Pb/Ag, Pb/Ag/Al, Pb/Cu, Pb/Ag/Sn (125*100*1mm)

Pb

Pb

Pb

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Documents

Report on special „LEAD-MEETING“ at CERN on May-18 2004