Cleanrooms Keith Middleman

Particulates and Clean rooms What is a particulate? Small discrete mass of solid or liquid. Human hair is microns in diameter. Micron = 1/1,000,000 of a metre. What is a clean room? A specially designed room to achieve a specific ISO standard. A filtered distributed air supply. Set of operating and regulatory procedures. A manager.

Particulate origins Where do they come from? All around us. Equipment, process, clean room materials. From us, 10Ks particles / min depending on type of clothing worn.

Low particulate experience on ALICE ALICE Photoinjector vessel In ISO 4 Cleanroom

ISO cleanroom standards Class maximum particles/m 3 FED STD 209E equivalent ≥0.1 µm≥0.2 µm≥0.3 µm≥0.5 µm≥1 µm≥5 µm ISO ISO ISO 31, Class 1 ISO 410,0002,3701, Class 10 ISO 5100,00023,70010,2003, Class 100 ISO 61.0× ,000102,00035,2008,320293Class 1,000 ISO 71.0× ×10 6 1,020,000352,00083,2002,930 Class 10,000 ISO 81.0× × ×10 7 3,520,000832,00029,300 Class 100,000 ISO 91.0× × × ,200,0008,320,000293,000Room air ESS BTM vessels to be particle tested to ISO 5

Signs are important.

Changing room. Sanitise & moisturise

Once all vacuum work in the vacuum laboratory is completed the vessel or component is then transferred to the area outside the clean room and prepared for the cleanroom Cleanrooms Vessels are wiped down with tack cloths All surfaces cleaned and wiped down with IPA wipes Vessels blown off with high pressure filtered N2 Allow time for any particles to settle and then open doors for transfer into the clean room Vessels are transferred into the outer area of the cleanroom – ISO6 and are left for a number of hours before they enter the main ISO4 assembly area

Cleanroom Change 6m 2 ISO 7. Outer 80m 2 ISO 6. Inner 12m 2 ISO 3. at rest

Cleanroom Change 6m 2 ISO 7. Outer 80m 2 ISO 6. Inner 12m 2 ISO 3. at rest

LWU Particle Counting Particle counts to be taken in 4 positions Purge vessel with 0.5 bar N 2 Measure particle count Purge vessel with 0.5 bar N 2 Measure particle count Particle counts to meet ISO 5 on 5 consecutive occasions before moving to the next position

Particle counting procedures 1.A one minute sample of particle level should then be taken and checked to ensure it meets the ISO 5 standard. If it does not then the chamber should be left for a further 30mins and the area retested. If it is still not below the required level then the chamber should be moved back out to the changing area and re-cleaned with a lint free wipe and blown down with N 2. 2.The chamber then should be un-flanged, to do this remove all but two bolts from the flanges (note: this will produce an increase in the particle count) then let the chamber settle again and take another one minute particle count. Then remove the flanges and take a one minute area sample to check ISO class. 3.If ISO 5 is not achieved wait a further 30mins and take a further sample. Repeat this upto 5 times. If the area still does not reach the required level the chamber should be removed and the process re-started. 4.Once the area is acceptable blow the internal chamber surfaces with filtered N 2 at 7 bar. The chamber should then be tapped delicately a number of time across the surface with a rubber mallet. This, N 2 blow then tapping procedure, should be repeated twice more. 5.Then take a one minute sample at the location specified for the unit whilst purging at 0.5 bar with filtered nitrogen. This should be done remotely if possible. 6.Repeat stages 4&5 four more time, recording the counts each time. 7.If each of the particle counts in stage 5 meets the ISO5 specification seal/cap the vessel – passed 8.If any of the particle counts in stage 5 do not meet ISO5 repeat another 5 times, if vessel repeatedly fails then speak to area supervisor.

Cleanrooms After acceptance of the vacuum component it will be vented with pure ‘dry’ filtered N 2 Filtered down to 0.1µm ‘Dry’ - N 2 purged until a dew point of - 70 ⁰ C is measured, keeping moisture down to acceptable low levels Vessel is capped and remains under a N 2 atmosphere

Particulate counting Unfiltered 12 mins of filtering later. Printed result & data file to be saved to database

Particle counting issues STFC experience with ion pumps: Could not condition all ion pumps down to ISO5 Ion pump specification relaxed to ISO6 Decision taken to locate all ion pumps on ALICE beneath the beamline or girder so any particles generated would be captured in the base of the ion pump due to gravity NEG pumps: Given the nature of the NEG pumps having a huge surface area and very difficult to particle count, they were blown with 0.5bar N 2 but they were also positioned beneath the beamline.

Controlled venting and evacuation Aim to implement similar procedures for ESS Venting and Evacuation rates have been agreed to be < 20 mbar per minute to avoid turbulent flow STFC Design option is a combination of In-house design Modular unit purchased from industry Pumping solutions – do not need to be assembled under particle control conditions but some procedural arrangement is required Dedicated procedure to be agreed and implemented across both sites to guarantee ISO particle standards are maintained

Controlled venting and evacuation

Mobile Installation Cleanrooms

Mobile cleanroom used during ALICE build Modular design for use in multiple locations to enable different modules to be connected in the accelerator tunnel Cleanroom and vessel preparation procedures in the mobile cleanrooms are the same as those in the dedicated cleanrooms. Only when ISO5 is established in the mobile cleanroom can the end flanges of each module be removed and the 2 modules connected together Each modular cleanroom has 2-3 parts: Changing area Tool storage area Main working area where flanges are to be connected

ESS Mobile Cleanroom Requirements

Timescale & Plan 1 st mobile cleanroom to be delivered late further mobile cleanrooms to be delivered by Q A total of 3 mobile cleanroom to be delivered (as specified in the technical annex) Once STFC/ESS have agreed on the specification STFC will go out to UK manufacturing to have the cleanrooms manufactured in industry. STFC will conduct a site visit and perform an acceptance test at mnaufacturer’s. Manufacturer to ship directly to ESS.

Similar Systems Conventional mobile cleanroom Cantilevered solution

Thank You

Once all vacuum work in the vacuum laboratory is completed the vessel or component is then transferred to the area outside the clean room and prepared for the cleanroom Cleanrooms Vessels are wiped down with tack cloths All surfaces cleaned and wiped down with IPA wipes Vessels blown off with high pressure filtered N2 Allow time for any particles to settle and then open doors for transfer into the clean room Vessels are transferred into the outer area of the cleanroom – ISO6 and are left for a number of hours before they enter the main ISO4 assembly area

Change area 6m 2 - ISO 7 Outer area 80m 2 - ISO 6 Inner area 12m 2 ISO 3 at rest ISO 4 with 1 person working ISO 5 with 2 people Cleanrooms All vacuum vessels will be transferred into the cleanroom on dedicated cleanroom trolleys which are to be designed

Particle Control Options – full assembly BPMs Difficult to blow out with N2, when cleaning bellows, just pushing particulates into chamber? Also how difficult will counting at this end be if we are blowing the N2 2m away? I’m guessing the counts will be low. Particle control as a complete assembly or not? - Discuss

Particle counting options – split assembly Particle count each part separately then bolt together. BPM blocks can be either welded onto the chamber or flanged.

Summary Report 1-2 page summary after all vacuum processes complete Printed particle count results to included with the report along with the job card