MHI#15 号機の２回目の EP2  Process log  Status of working  Monitor data during EP & Rinsing process  Comparison of EP2 Period : 2011/2/22 ~ 2/28 Process : EP2(20μm) under low current density, Improved 1 st Water Rinsing, & Flange using FM-20, Degreasing(FM-20, 2%) [1hour], HPR x 2 [10 hours], Assembly in C.R., Vacuum evacuation, Leak check, ℃ (48hours) Preparation : Washing vacuum components with ultrasonic, Cleaning in C.R. Workers : M. Sawabe, Kirk, M. Satoh, T. Shishido (KEK), K. Nakamura, N. Tasaki, F. Tsukada (Assist Engineering Co.), T. Okada (K-VAC), S. Imada (Nihon Advanced Technology) Kirk 1 STF Cavity Group

2 EP acid (2/23 のサンプルを使用 ) Nb ingredient : 8.4g/ℓ HF ingredient : 28 g/ℓ ( 全体 38g/ℓ の 65% が反応に使われる ) Al ingredient : 15mg/ℓ Current density : ～ 37mA/cm 2 ( 最近の傾向より ) Cavity surface temperature : <35 ℃ Control Voltage : 温度と電流密度を見ながら制御 With normal N 2 gas flow during extracting EP acid (8ℓ/min) 1 st water rinsing (1.5hours) Improved version (25ℓ/min で 20 分間上下から流し続ける ) 1 分毎に 1 秒間水抜きを繰り返す (40 分間 ) 最後の 30 分は 10min (storing)/3min (flushing) で行う Degreasing (1 hour) FM-20(2%) HPR ( ～ 10 hours) 5h17m (6 turns, w/o blind flanges) 4h25m (5 turns, w/ blind flanges) Condition of EP2 & Rinsing & Flange using FM-20 using FM-20 EP2 を 1 ～ 2 回行ったぐらいではたいして変化しない

Process log ① STF Cavity Group 3 2/22 9:00Check every flange / Hit trace was observed at input port 10:45~Attachment of jigs for EP / HPR operation starts without cavity 11:28Set cavity to EP bed with crane 11:48Installation of cathode bar to cavity Lunch time 13:00Set data logger to cavity (totally 12ch) Leak check with N 2 gas [O.K.] 13:30Meeting for tomorrow’s working procedure 13:50~Vacuum parts rinsing with ultrasonic in C.R. 15:00fin. / HPR stops due to high T.O.C.

STF Cavity Group 2/23 9:47Cavity rotation starts / EP acid flow starts 9:59EP2 starts 11:11EP2 stops [1h12m00s] / Idling rotation (3 rpm / 20min) / Plastic case detachment 11:30Idling rotation stops 11:32EP acid is removed from cavity with N 2 gas flow(0.020MPa) 11:44First rinsing with ultra pure water starts 13:14First rinsing with ultra pure water stops [1h30m] 13:22Detachment of restriction jigs / Data logger detached 13:40Un-installation of cathode bar from cavity / washing cathode bar (No black mark) 13:52transferring cavity from EP bed to wagon / Checking inside cavity 14:14Detachment of jigs for EP / Detaching every blind flange / Checking inside cavity (White mark exists!) 14:30Brushing at every flange using FM-20 / Shower rinsing 14:45Checking inside cavity (White mark still exists!) 14:50Attachment of flanges for degreasing 14:55Flowing FM-20 into cavity 14:59Degreasing with ultrasonic starts 15:59Degreasing with ultrasonic stops [1hour] 16:02Removing FM-20 from cavity 16:10Detachment of flanges for degreasing 16:16Brushing at every flange using FM-20 / Shower rinsing / Checking inside cavity (White mark still exists!) Process log ② 4

Process log ③ STF Cavity Group 5 2/2316:30Transferring cavity from wagon on turntable for HPR using crane 16:36Checking tolerance between position of nozzle and center of beam pipe 16:481 st HPR for inside cavity starts 22:051 st HPR for inside cavity stops [5h17m] (6 turns) 22:10Attaching only top flanges in C.R. 22:35fin. 2/24 9:00Attachment of blind flanges at bottom beam pipe for 2 nd HPR 9:15HPR outside cavity with blind flanges starts [15mins] 9:352 nd HPR for inside cavity with blind flanges starts During HPR, cover of rotation mechanism was broken! 13:572 nd HPR for inside cavity with blind flanges stops [4h25m] (5 turns) 14:00Cavity enters into C.R. 14:30Assembly in C.R. (Class 10) starts(type of helicoflex is changed from In to Sn coating) 16:00Assembly in C.R. (Class 10) finishes / Moving out from Class10 to Class :07Vacuum evacuation starts with heat guns 16:17Turbo pump status 100% (Normal operation, but abnormal noise) 16:40Leak check -4 Pa  Leak occurred at ICF gasket between bellows Re-assembling using new Cu gasket / Re-pumping down / Re-leak check  O.K. ℃ starts using new temperature controller Max Vacuum Level just after baking start : ~1.4 x Pa 18:15Cavity vacuum : 6.63 x ℃ /102 ℃ /64 ℃ /67 ℃ (Cell#3/Cell#7/Top/Bottom) 19:08Cavity vacuum : 2.31 x ℃ /105 ℃ /71 ℃ /77 ℃ (Cell#3/Cell#7/Top/Bottom) 20:49Cavity vacuum : 1.00 x ℃ /105 ℃ /78 ℃ /81 ℃ (Cell#3/Cell#7/Top/Bottom)

Process log ④ STF Cavity Group 6 2/25 9:30Cavity vacuum : 2.07 x ℃ /105 ℃ /82 ℃ /84 ℃ (Cell#3/Cell#7/Top/Bottom) 9:35Additional aluminum foil is attached to both beam pipes 13:05Cavity vacuum : 2.12 x ℃ /105 ℃ /85 ℃ /90 ℃ (Cell#3/Cell#7/Top/Bottom) 17:40Cavity vacuum : 2.04 x ℃ /105 ℃ /86 ℃ /91 ℃ (Cell#3/Cell#7/Top/Bottom) 2/2621:15Cavity vacuum : 1.31 x ℃ /105 ℃ /86 ℃ /90 ℃ 21:25Baking Off [52hours] / Ion Pump ON 21:40Cavity vacuum : 2.35 x ℃ /87 ℃ /82 ℃ /84 ℃ 2/28 9:10Cavity vacuum : 0.98 x Pa / I.P head : 0.0 x Pa 9:45MHI#15 goes out of clean room and moves to V.T.A.

Status of working ① STF Cavity Group 7 壊れた HPR の昇降機構のカヴァー

Status of working ② STF Cavity Group 8 EP 後にブラシングをかける

Status of working ③ STF Cavity Group 9 白い縞模様の変遷 1 回目の EP2 後 1 回目の V.T. 後 2 回目の EP2 後 (1 回目とは模様が異なって いるようである )

STF Cavity Group Status of 2 nd EP2 for MHI#15 ① 10 current voltage T cavity T reservoir T room T cavity average current density 平均電流密度が 37mA/cm 2 程度になる ように電圧を調整する。 (low current density EP)

11 STF Cavity Group Status of 2 nd EP2 for MHI#15 ② 左図は平均電流密度と電圧の相関 右図は定常状態での分布 target

最近の定常状態の比較 STF Cavity Group 12 Cavity Mean temp. [ ℃ ]R.M.S. temp. [ ℃ ] Mean i [mA/cm 2 ]R.M.S. i [mA/cm 2 ] MHI-A 1 st MHI#12 1 st MHI#13 1 st MHI#12 2 nd MHI#13 2 nd MHI#14 1 st MHI#15 1 st MHI#14 2 nd MHI#15 2 nd 電流の振れ幅は前回よりさらに小さくなった。 だんだん液がヘタってきているものと思われる。

Status of 2 nd EP2 for MHI#15 ③ STF Cavity Group 13 #1#2#3#4#5 #6#7#8#9#10 EP2 の間の空洞表面温度の状況。 #11 #12

Status of 2 nd EP2 for MHI#15 ④ STF Cavity Group 14 #1#2#3#4#5 #6#7#8#9#10 EP2 の間の空洞表面温度の状況（前ページの最後の拡大図）。 #11 #12

STF Cavity Group 15 #1#2#3#4#5 #6#7#8#9#10#11 #12 Status of UWR for MHI#15 ① 通信不良によるデータの跳びが無くなった。

STF Cavity Group 16 一次洗浄中の空洞温度の状況（前ページの拡大図） #1#2#3#4#5 #6#7#8#9#10#11 #12 Status of UWR for MHI#15 ②

Status of UWR for MHI#15 ③ STF Cavity Group 17 ①は最初の注水完了時。 ②は流量を増やした状態での洗浄中。 ③は流量を減らした状態での洗浄中。 ① ② ③

STF Cavity Group Status of HPR for MHI#15 18 ノズルは 1st HPR では６往復、 2nd HPR でも５往復させた。 HPR の昇降機構を防護するカバーが壊れたため、 ２回目の途中から TOC も particle も増加傾向にある。