1. Quality control of EP in KEK-STF TTC meeting April 21 st 2010 FNAL Motoaki SAWABE

2. EP facility in KEK-STF We have constructed an Electro-polishing (EP) Facility in the Superconducting RF Test Facility (STF) at KEK at the end of 2007, and have begun to operate from 2008. In the EP facility, the capacity of the EP-electrolyte reservoir tank is 2,000 L. This size is relatively large if compared with EP facilities in other Laboratories. we circulated the EP-electrolyte of 1,100 L in the tank. It means that the quality control of EP-electrolyte is more difficult because the status of EP-electrolyte changes as the aging of EP- electrolyte proceeds. We firstly poured new electrolyte into the tank in December 2007 and disposed it in May 2009. During this period, we performed 41 times EP by this electrolyte. And we poured new electrolyte in May, 2009 too. We perform 43 times EP after it.

3. The EP Process in KEK-STF The EP process is usually the following processes. (Fine-EP) Flange CPEPDetergent Rinse Ultra Pure Water RinseHPR 1Hr.at 50 ℃ Clean Room

4. Management of EP-electrolyte We measure the concentration of niobium and aluminum in the electrolyte by Inductively Coupled Plasma - Atomic Emission Spectrometry. (ICP) And we measure the fluorine concentration by steam distillation method and Ion Selective Electrode (ISE). All fluorine is measured as a fluorine ion by this method. (Next) We divide the measurement fluorine into the niobium oxygen complexes fluorine and other fluorine. We find the fluorine quantity of the niobium oxygen complexes by the calculation from this molecular weight and niobium concentration. (H 2 NbFO 5 ) ICP Steam distillation Present EP-electrolyte samples

5. Fluorine in a EP-electrolyte The electrolyte diluted solution is divided into hydrogen fluoride and fluorosulfuric acid and niobium oxygen complexes. All fluorine is distilled as a fluorine ion by steam distillation method. EP-electrolyte(1/1000)Fluorosulfuric Acid(1/1000)

6. Old electrolyte data We performed 41 times EP in the old electrolyte. (From January, 2008 to May, 2009) These are removal weight at each EP and adding up this. Removal weight (g)Adding up weight (g)

7. Niobium and Aluminum concentration These are the changes of niobium and aluminum concentration in the old electrolyte. The change of niobium concentration almost accorded with removal by EP. The concentration of aluminum increased in the same way as it of niobium. Niobium (g/L)Aluminum (mg/L)

8. Fluorine concentration These are the changes of fluorine concentration in the old electrolyte. While the EP processing for about 1 year 6 month, about 20% fluorine leaked out and about 16% fluorine was used for reaction with the niobium. Total F (g/L) F as H 2 NbOF 5 (g/L) F as HF (g/L)

9. EP logging data We are recording various logging data of EP automatically every one second. (formed CSV) We pay attention to EP current oscillation in particular in them. We compare EP current oscillation of last 1 minute with the niobium concentration. This oscillation pattern changes by the niobium concentration. (Next) Current Current Density Cavity Temp.Voltage Reservoir Tank Temp. Removal (μm) Flow

10. This is the change of oscillation pattern of last 1 minute. ( at EP current about 250A) Nb: 1.8 ｇ／ｌ Nb: 3.2 ｇ／ｌ Nb: 5.4 ｇ／ｌ Nb: 8.5 ｇ／ｌ Current Current Density

11. The comparison of EP current oscillation These are comparison of EP current oscillation. We understood that the EP current oscillation pattern became smooth and small as electrolyte aging. And this oscillation pattern changed at 4 ～ 5g/L niobium concentration. New electrolyte had the same tendency too. Old electrolyte oscillation New electrolyte oscillation

12. Temperature management We measure various temperatures with the thermo-viewer. We measure several times during EP processing. Intake air or N2Exhaust air or N2 Electrolyte inElectrolyte out(L)Electrolyte out(R)

13. Temperature management (2) The cavity surface temperature has temperature oscillation with the turn. We examined by the thermo-viewer where temperature became higher most. We understood that the upper part of electrolyte level was higher temperature. We thought that we cooled there. Max. Max Non-reflection tape

14. Max. Non-reflection tape

15. Cooling method of a cavity We thought that we cooled the cavity surface by a cold wind. Cold Wind Fan 9℃9℃

16. Cooling method of a cavity (2) The temperature of cavity inside and surface has a considerable difference. Therefore we observe the surface temperature of equators and beam pipes. We prevent a rise of the surface temperature by cold wind. And we suppress the partial temperature rise by the cold wind and can keep the temperature stability. Cold wind start The direction change of the wind

17. Detergent Rinse We fill a detergent to a cavity and we put it in a hot bath of 50 degrees Celsius and perform an ultra sonic cleaning of 1 hour. When we use the detergent, we fill it from the cavity bottom by the pump. When we use the ethanol, we fill it from the cavity top by hand. We use 2%FM-20(detergent) mainly now. We gather the detergent sample of washing before and after. Detergent tank (50L×2) Detergent IN OUTEthanol rinse Pump

18. ERL2cell#2cavity 20μmEP(Feb.24,2010) 2% FM-20 rinse with ultra sonic for 1 hr. at 50 ℃. We filtered 2%FM-20 100ml after the rinse by 0.45μm Omunipore Menblane Filter.(n=3) The blank is before rinse. (n=1) We analyze them by XRF. Sample ① Sample ② Sample ③ Blank Sample and Blank XRF analyzer AfterBefore Detergent Rinse (2)

19. Sample ① Blank S-Kα Al-Kα Detergent Rinse XRF Scan Ge-PC S-Kα Al-Kα At first we scan sulfur and aluminum. It is because sulfur sublimates by X-rays. Aluminum and sulfur are detected at the same time till now. In the lower chart a very small amount of sulfur and aluminum were detected

20. Detergent Rinse XRF Scan FLi-SC Next we scan heavy metal. In the lower chart niobium was detected clearly. Nb-Kα Sample ① Niobium was detected by all of sample ①, ②, ③. Niobium

21. Detergent Rinse XRF Scan Ge-PC AES9cellcavity#3 50μmEP(Oct.9,2009) 2% FM-20 rinse with ultra sonic for 1 hr. at 50 ℃. We filtered 2%FM-20 100ml after the rinse by 0.45μm Omunipore Menblane Filter.(n=3) The blank is before rinse. (n=1) In their chart sulfur and aluminum were detected clearly. Sulfur, Aluminum S-Kα Al-Kα

22. The detection of the dissolved sulfur. A dissolved sulfur has absorption spectrum near by 260nm. We detect a dissolved sulfur by absorption spectrum. FM-20 can dissolve a very small amount of sulfur. As for the ethanol, it is removed a small quantity. This method is effective in ethanol rinse. 260nm FM-20 260nm Ethanol

23. Management of waste water We measure the waste water from the facility in the same way as an electrolyte. From January, 2008 to May,2009, we performed EP of 41 times. We transferred the waste water eight times in this period. And we transferred the old electrolyte for a disposal. We calculated about the material income and expenditure of fluorine and niobium in this period. Waste water transfer Old electrolyte disposal

24. The flow of the fluorine and niobium in the EP processing. Exhaust Waste water Discharge out of the system Discharge out of the system Income Disposal Removal of Niobium Electrolyte The material income and expenditure.

25. Exhaust Gas The exhaust gas is detoxified with an absorption tower, and it is discharged in the atmosphere. The absorption tower is made in series at two towers. And alkaline water circulates through the inside. The hydrogen fluoride in exhaust gas is completely removed.(Next) Alkaline absorption water is sent to the waste water tank regularly. NOx Monitor NaOH Tank Inducement Fan No.1 Tower No.2 Tower

26. Fluorine concentration in absorption towers No.1 Tower Hydrogen fluoride in an exhaust gas is removed completely with No.1 absorption tower. Now we are holding down exhaust time and volume as much as possible to prevent loss of the fluorine by gas. Fluorine concentration

27. The material income and expenditure Date Carry Volume (l) Concentration of Fluorine (mg/l) Weight of Fluorine( g) Concentration of Niobium (mg/l) Weight of Niobium (g) Disposal 2008/1/11900130117--Treatment Plant in KEK 2008/2/1600350210--Treatment Plant in KEK 2008/2/15900650585--Treatment Plant in KEK 2008/2/291000340 --Treatment Plant in KEK 2008/6/197,5001601,2008.161Treatment Plant in KEK 2008/11/1 8 7,5002702,02514105Treatment Plant in KEK 2009/4/176,8002701,83617116Treatment Plant in KEK 2009/5/141,10039,00042,9007,8008,580The Outside Disposal 2009/5/2210,0003903,90065650The Outside Disposal Total36,300 53,113 9,511 Date Carry Volume (l) Concentration of Fluorine (mg/l) Weight of Fluorine( g) Total Removal Nb Weight (g) 2007/12/2 6 1,10049,00053,900-9,433 Income Expenditure Electrolyte The lower table is the income and expenditure of the old electrolyte. The material income and expenditure almost matched.

28. The material income and expenditure While the EP processing at KEK-STF facilities for about 1 year 6 months, the material income and expenditure of fluorine and niobium almost matched. Fluorine of 10,000g in the electrolyte leaked out in this period. This quantity is about 20% of the income. This fluorine mixed into the waste water. Niobium of 930g of EP removal mixed into the waste water. This quantity is about 10% of the all removal.

29. My present study We judge the aging of EP-electrolyte from the concentration of niobium and fluorine. Will it be only them? EP-electrolyte has the fluorescence with the aging. I examine the aging and fluorescence about EP- electrolyte. Excitation ( nmλ ) Emission ( nmλ ) Intensity New electrolyte Aging Electrolyte samples

30. Thank you.