Pb 1 Report on special „LEAD-MEETING“ at CERN on May 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

Pb 2 The two extremes: Pb & Pb-Ca Breaking point tearing (fluidity region) elasticity region of Pb-Ca

Pb 3 Tensile tests on different Pb alloys (as was provided by JLGoslar) SamplesRm (MPa)Rp0.2 (MPa)Elongation (%) Pb (99.99%) Pb+Cu0.05 ASM values (Chemical Lead %Pb) Pb+Ag0.015+Al Pb+Ag0.015+Sn Pb+Ca (0.08 %) ASM values (Pb-0.07Ca) did probably not contain Al

Pb 4 The 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 )

Pb 5 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 BUT in view of the problems it is wise not to further entertain a Pb-Ca solution for the moment Switch to page 18

Pb 6 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

Pb 7 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

Pb 8 XPS detection limit Element “concentration” (at.%), XPS Ca in Pb as-received, NGL cleaned, storage

Pb 9 Analysis 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

Pb 10 XPS analysis of the emulsion (results in atomic %)

Pb 11 Ca in Pb as a function of storage method

Pb 12 XPS results: side exposed to emulsion

Pb 13 Hardening of the PbCa by precipitation of the Pb 3 Ca compound

Pb 14 Pb-Ca alloys Four 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, ˚C

Pb 15 Pb-Ca-Sn Alloys Pb-0.11wt.%Ca-xwt.%Sn x = 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.

Pb 16 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

Pb 17 Effect of Ag Pb-0.08wt.%Ca-1.11wt.%Sn wt.%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.

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

Pb 19 Placement of priorities and urgencies Proposal: 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.

Pb 20 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

Pb 21 Cleaning recipe from CERN TSG

Pb 22