report on special „lead-meeting“ at cern on may-18 2004
DESCRIPTION
Report on special „LEAD-MEETING“ at CERN on May-18 2004. Compatibility issues mechanical hardness needed for BAM chemical compatibility with emulsions irrespective of packaging option (vacuum or mechanical) Placement of priorities and urgencies further test w/ emulsions ?? - PowerPoint PPT PresentationTRANSCRIPT
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
New representation of the hardening processes of lead alloys by transformation-time-temperature (TTT) diagrams J.R Hilger, L. Bouirden, 1995.
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
New representation of the hardening processes of lead alloys by transformation-time-temperature (TTT) diagrams J.R Hilger, L. Bouirden, 1995.
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
Pb