Absorber Design Concept RIKEN/RBRC Itaru Nakagawa 1

2.34 meters  56cm ２ 1cm 35 cm 37° 10° 16cm A (thickness 16cm)B (thickness 19cm) Volume0.38 m m 3 Net Weight3.4t5.2t 19cm ２ 7cm Material : Copper, Brass, Bronze, Stainless Steel Total 8.6t 2

3 １２ ３ ４ Since Flower pot is tapered, we cannot install absorber from the back if absorber is made in one body. Ring design also faces same installation problem. Since Flower pot is tapered, we cannot install absorber from the back if absorber is made in one body. Ring design also faces same installation problem. Thus the present idea is to segment front and back absorbers into 4 pieces, respectively. Total 8 pieces. Thus the present idea is to segment front and back absorbers into 4 pieces, respectively. Total 8 pieces.

4 １２ ３ ４ If the company make the absorber by casting of whole absorber and then chop into pieces, then there will be space in the order of a few mm. If they do machining each pieces, then the joints will be exact (less than mm). If the company make the absorber by casting of whole absorber and then chop into pieces, then there will be space in the order of a few mm. If they do machining each pieces, then the joints will be exact (less than mm). We’ll fill out this gap with spacers, if we found it is necessary.

Constraint of Installation absorber Counter weight Crane Max = 12t Each absorber piece Is preferably less than 2 tons. (Don)  8 pieces segmentation brings each piece about 1t. Each absorber piece Is preferably less than 2 tons. (Don)  8 pieces segmentation brings each piece about 1t. 5

~ 25cm Interference w/ BBC Cables BBC cables are running at 25 cm elevation from the surface of central magnet back. We need to re-route cables at the elevation of 35cm on top of the absorber back surface. BBC cables are running at 25 cm elevation from the surface of central magnet back. We need to re-route cables at the elevation of 35cm on top of the absorber back surface. Andrew Cables Andrew cable/connectors are very stiff. Minimum bending angle and number of times are strictly limited. 6

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Modification of BBC Patch Connection 8

Flower Pot Design (South) 10cm New patch panel (66mm) 9

Available Space 90mm 10

Japanese Companies CompanyMaterialManufactureQuoteComment Izumi Metal / Akaboshi co. ltd. BronzeCastingNext weekConfident in time Sumitomo Heavy Industrial ltd. BrassCasting$300kDifficulty in time Copper PlateFaster, but 4 layers Hitachi Engineering Oxygen Free Copper Forging3/18 Yuasa Ltd.BrassCastingNext week Tohoku Oye Industry Next week Takano GikenBrassNext week OkamotoBrassCasting $220k + machining 11

Stainless Steel CompanyMaterialMachiningQuoteComment Giken-Seiki Co.SUS310?Lathe Turning Experienced w/ SUS316 B<40uT Iijima Machinary Co. Appointment 3/19 Yagita Giken Co.SUS310?ASAP Inoue Material Need Drawing to Estimate 12

Permeability of SUS 13