# Presentation: 490225

## 

Update on Cleanroom, Clean water,
 HPR systems and Field Emission
J. Mammosser (Jlab) 

- Update on Cleanroom, Clean water,
-  HPR systems and Field Emission
- J. Mammosser (Jlab)

## Outline

- Quick Review of Cleanroom, DI water and HPR Details
- Discussion on DESY and JLAb facility operations ( A. Matheisen, N. Krupka, L. Lilje, J. Mammosser)
- Field emission at Jlab, what is our approach to solving
- Discuss Jlab plans IP3I (C. Reece)
- Review of the DESY process steps with these facilities in mind
- Review WG5 R&D recommendations (Cleanroom, DI water, HPR)
- Review current list relating to these facilities (L. Lilje)
- Identify details of each item in the list
- Review Care and DESY efforts

## Cleanroom Facilities

- With current “State of The Art” processes
- All of the final cavity and subcomponent cleaning taking place in the cleanroom areas as standard procedure
-  HPR system fully integrated into facilities
-  All critical assemblies taking place in Class 10
-  **The cleanroom is one of the major critical facilities in the current process !!**
- What is the current state of SRF facility monitoring, cleaning and maintenance?

## Cleanroom Facilities

- Facility cleaning:
- DESY  Has external cleaning staff that starts at the end of the work shift as well as DESY staff that perform some cleaning steps when necessary
- Floors daily and walls once per week
- JLAb  Has external cleaning staff that starts during the day and Jlab staff perform major facility cleaning after maintenance downs and when necessary
- Floors and trash daily
- Walls and filters every 6 months or prior and after string assembly

## Cleanroom Facilities

- Maintenance
- DESY 
- Once per year blowers , pre filters etc
- Jlab 
- Once per year blowers , pre filters ect
- Require cleaning of blower housing and balancing of room pressures
- Twice per year opportunities for general maintenance during 1 week downs
- Require cleaning of full facility after facility shutdown

## Cleanroom Protocols

- Staff Training
- DESY 
- Training of staff – On the job  training with particle counters to qualify
- Outside training was performed in the past
- Plan to use return air particulate monitoring
- Jlab  This needs much improvement!! (IP3I)
- Training of staff – On the job from senior staff
- Outside training and videos used in the past

## Cleanroom  Protocols

- Entry
- DESY 
- Allows up to 4 personnel in Class 100 at a time
- Allows 2 personnel in Class 10 at a time
- During module assembly 3 allowed , 2 working and 1 backup
- Jlab 
- No limit but typically 4 or less total unless cleaning than up to 6
- Class 10 area so small it only fit 2 working
- Personnel required to sign in logbook prior to entry and exit

## Cleanroom Monitoring

- DESY 
- Fixed locations for particle counting
- Fixed locations for QC steps
- Jlab 
- Fixed locations for particle counting all major areas
- All areas still meet design standards (1990)
- No impact from number of personnel in facility on system performance
- Portable counters for process assembly steps
- Independent certification of all production cleanroom facilities 2002

## What Changes Would You Make? 

- DESY  SRF 2005 Poster (K. Escherich et. al.)
- Cleanroom Facilities For High Gradient Resonator Preparation
- Supply and maintenance areas accessible from out side
- Filter fan units to reduce recovery time
- Independent air supply for chemistry – safer
- Better product flow to reduce cross contamination, one way path
- Jlab 
- Outside consultant identified many things , here is just a few!
- Improved cleaning of components prior to entry
- Separate area for nitrogen cleaning of sub components
- Reduction of amount and type of hardware entering facilities

## DI Water System

- Monitoring
- DESY 
-  Online measurements of TOC and Resistivity
- Measuring points
- (Plant) between inline filter and UV lamp
- 7 POU locations routinely measured 2-3 days
- Bacteria checked every three weeks random POU locations
- Filter drain water for particle counts – poor correlation with performance
- Jlab 
-  Online measurements of TOC, Resistivity and particle counts after final filter HPR
- Full analysis including Bacteria once per year, HPR and plant, next FY once per quarter smaller set monthly
- Particle counts poor correlation with performance

## DI Water System

- Makeup Rate
-  DESY 800-1200 l/hr
- Jlab 1000-1200l/hr
- Typically running most of the day, 2 HPRs , back flush at night
- Maintenance similar for both DESY/JLab
- Sanitize whole system once per year, replace filters polishers ect.
- DESY –changes polishers every 2 weeks, resistivity low 17-17.5 ion exchange bottle rotation
- Jlab – US Filter maintenance contract, ion exchange bottles on resistivity monitor , Virgin resin only
- DESY – started preconditioning filters in separate loop to save flushing time

## DI water Performance

- DESY Particle Counts 0.22um
- HPR POU Inlet
-  25 counts/l
- HPR Head (off)
- ~22.8 counts/l
- Chemistry supply line
- ~25 counts/l
- TOC Data
- 1.5-0.4 ppb

- Jlab Particle Counts 0.2um
- Plant final filter (HPR POU)
- 80 counts/l
-  HPR Wand (on)
- 1600 counts/l
- TOC Data
- 40-1 ppb

## Typical JLab HPR Data

## HPR  System

- HPR system is the single most important cleaning process to reduce field emission currently used and is the cavity final cleaning step
- After chemistry the cavity surface is in most contaminated state
- Flow through rinsing following chemistry is not enough to reduce field emission consistently

## HPR System

- Specifications:
- DESY 
- Pressure -100 bar, LEWA Pump
- Flow rate ?
- 0.04um final filter
- Steam clean weekly to clean and kill bacteria
- New system design with a lot of changes
- Jlab 
- Pressure – 100 bar, LEWA Pump
- Flow rate 15 lpm, off 1-3 lpm
- 0.04um final filter
- Steam clean every 3 months

## Jlab Water Analysis

- Typically Analysis : (BALAZS Analytical Services)
- 		W0102 – Bacteria-ASTM Method
- 		W0106 – Total Oxidizable Carbon
- 		W0117 – Dissolved Silica
- 		W0120 – Total Silica
- 		W0121 – Anions by IC
- 		W0123 – Monovalent & Divalent Cations by IC
- 		W0128 – 68 Trace Elements in Ultrapure Water

## Jlab Water Quality

|   |   |   | Sep-05 |   | Feb-04 |   | Aug-03 |   |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Measurement  | RL | Units | HPR (0.04um) | Plant (0.2um) | HPR (0.04um) | Plant (0.2um) | HPR (0.04um) | Plant (0.2um) |
| TOC  | 5 | ppb | 36 | 9 | 13 | 8 | * | * |
| Dissolved Silica | 0.1 | ppb | 0.1 | * | 3.3 | 3.1 | 1 | 1 |
| Total Silica | 0.5 | ppb | * | * | * | * | 1.5 | 1.7 |
| Anions Cl- | 0.02 | ppb | * | * | 0.08 | 0.07 | * | 15 |
| Cations Na+ | 0.01 | ppb | * | * | 0.22 | 0.21 | not meas. | not meas. |
| Trace elements |   |   |   |   |   |   |   |   |
| Boron | 50 | ppt | 940 | 920 | 860 | 830 | * | * |
| Potassium | 10 | ppt | * | * | * | * | not meas. | not meas. |
| Sodium | 5 | ppt | * | * | 0.2 | 0.19 | 0.29 | 0.3 |
| Bacteria/100mL | 1 | cfu | 36 | * | * | * | not meas. | not meas. |

## Jlab’s new strategy to improving cavity performance

**IP3I Strategy Just Starting (C. Reece)**
- Codify **procedures** – address everything we recognize as potentially affecting system performance
- Certified **training** to procedures developed, staff must demonstrate understanding and ability to follow them
**Culture** of discipline for following procedures and highlighting difficulties
- Meaningful **monitoring** of process parameters

## Jlab’s new strategy to improving cavity performance

**IP3I cont.**
- Structured **validation** of procedures
- Validate effectiveness and merit of current procedures not supported by hard data
- Confirm procedure accomplishes what was intended
- Independent procedure **improvement**
- When procedure is not effective or unnecessarily burdensome, consideration of potential modifications is addressed by careful analysis
- New process** development**
- Development of new methods requires involvement of staff with mixture of theoretical understanding and practical experience
- Validating criteria established , meaningful experiments mounted and interpreted

## Programs Identified at JLAb

- Procedure control improvements
- Documenting, training, qualification
- Integrate Nb witness samples into process steps BCP/EP
- Degreasing w/ detergent, Ultrasonic,  Drying
- Chemistry and water rinsing (Fill and dumps, Hot DI)
- HPR, assembly HPR
- Assembly, evacuation, RF testing
- Field Emission Viewer
- Nb Samples for production processes identify start of field emission and record digital image of location
- Transfer to SEM for analysis if necessary

## Field Emission Viewer

## Cleaning Procedure Verification

- Idea
- Use ionized nitrogen cleaning method to identify and verify process cleaning steps if resolution is good?
- Concept
- Mounted ionized gun to end of cane with 30  deflection nozzle
- Simple linear actuator and rotary table (spare from HPR)
- Mount particle counter at cavity end for data collection
- Analysis method
- By comparison of total counts
- After various cleaning steps and drying
- After good and bad vertical tests

## Ionized nitrogen cane

## IP3I cont.

- HPR Effectiveness Study (P. Kneisel)
- Goal is to understand the effectiveness of the HPR as a cleaning tool and optimize its performance
- Understand the impact forces on cavity surfaces
- Best methods for wand movements
- Cleaning effectiveness
- Ect.

## Field Emission

- I first reported that field emission was the dominant gradient limitation on CEBAF cavities at the SRF workshop in 1993
- At Jlab we have been fighting field emission ever since
- What do we know? (Mammosser)
- Many changes in procedures and facilities have occurred at Jlab since 1990
- At beginning no HPR   DI water soak, US DI water, Solvent rinse
- ~1% of CEBAF 5-cells performed at 20MV/m , Epk/Eacc = 2.54

## FE at JLab

- What do we know? (Mammosser)
- During SNS HPR pump was routinely failing
- We replaced our HPR pump (LEWA) after SNS production and had some improvement and is now fallen back
-  Multicell cavities have FE-onset much lower then single cells
- Our Production FE-onset is lower then DESY for most structures
- HG and LL structures have performed much better than other shapes
- Spread in performance is large

## Recent Single Cell Data 

## WG5  Identified R&D relating to these facilities

- WG5 efforts have produced a list of areas where R&D is necessary for BCD and well as ACD developments
- What is now needed is to flush out this list in more detail in order to:
- Capture details of the thinking behind why and what has to be solved
- This will allow for a broader audience to participate in solving problems and help in designing  and understanding results from  experiments
- Need to discuss what data exists and allow for future presentations to better understand the problem
- Write up the identified R&D requirements in detailed and formatted way

## DESY Process Steps

| Process Steps | Details |
| --- | --- |
| Electropolish Cavity |   |
|   | Final rinse and filled with UPW both ends sealed, Top flange blank, bottom EP rotary sleeve |
|   | Transport into cleanroom entry carwash |
| Degrease cavity |   |
|   | Car wash - spray outside with DI + detergent, DI final rinse |
|   | Transport into chemistry area |
|   | Ultrasonic cleaning exterior surfaces with Di water at 50C for 20 min. |
|   | Cavity exterior rinse, rinse to resistivity >14M-ohm-cm |
| Rinse cavity interior |   |
|   | Remove and replace all flange blanks and EP rotary sleeve, rinsing flanges added |
|   | Rinse cavity interior, 4 bar UPW rinse to 18 M-ohm-cm |
|   | Remove flange blanks |
|   | HPR cavity interior, 1X single pass, 100bar, 18 M-ohm-cm |

## DESY Process Steps

| Process Steps | Details |
| --- | --- |
| Dry cavity overnight |   |
|   | Transport cavity into Class 10 area |
|   | Store for drying over night |
| Preparation for vertical test |   |
|   | Transport to HPR system |
|   | HPR cavity interior, 3X single pass, 100bar, 18 M-ohm-cm |
|   | Transport cavity into Class 10 area |
|   | Store for drying over night |
|   | Assembly of antenna and flanges |
|   | Connect to evacuation system |
|   | Evacuate cavity |
|   | Perform Leak test |
|   | Transport to vertical teststand outside cleanroom |
|   | Insert into stand  |

## WG5  Identified R&D relating to these facilities

- Final cleaning **BCD choice**
**HP Rinsing, Dry Ice Cleaning**
**R&D necessary**
**Additional / improved monitoring on HPR**
- Particulates on input water - online
- Particulates on output water – online
- TOC
- Need a reliable system (Specification? Oil Contamination?)
- Online (High pressure side: JLAB, Low pressure side: DESY)
- Active carbon filter (KEK)
- Degassing of oxygen against bacteria (KEK)
- Dissolved solids
- Full water analysis (JLAb 1x year)
- Resistivity (all)

## WG5  Identified R&D relating to these facilities

**Improved cleaning power**
- Optimization nozzle material, geometry, size (Jlab)
- Optimize flow rates, impact angles (Jlab, INFN, Milano)
- Optimize pressure (Jlab)
- Investigate electrostatic charging
- Change on oxide structure, monitoring needed
- Optimize duration of rinse
- Quantify water quality needed
**Post HPR handling**
- Drying procedures
- Laminar flow in cleanroom (DESY,KEK, JLAb)
- Vacuum (DESY, KEK,Jlab)
- Understanding of the best vacuum system needed (Jlab)
- Oil Free (DESY)
- No particulate contamination

## WG5  Identified R&D relating to these facilities

**Drying procedures cont.**
- Hot nitrogen drying (Jlab) (with in-situ bake)
- Heating
- With evacuated cavity (KEK) In-situ bake
- Air Bake (SACLAY)
- Alcohol rinse
**Storage until test**
- Air, vacuum, clean nitrogen, argon
**Assembly**
- Standardization of cleaning methods for sub components
- CF. mass production
- QA of particle counts ect
- Main power coupler
- Can it be cleaned like the other components (before processing?)
- Documentation of assembly procedures

## WG5  Identified R&D relating to these facilities

**Assembly cont.**
- QA of particle counts ect.
- Training of people
**ACD priority 1**
**Dry ice cleaning**
**R&D necessary**
- Need Proof of principle on horizontal cleaning process
- Multi-cell issues need to be solving

## WG5  Identified R&D relating to these facilities

- Furnace Treatment
**BCD R&D necessary**
- Attach Furnaces to cleanroom
**Frequency tuning**
- Integration into cleanroom seems desirable ?

## Care and DESY efforts

- CARE
- Systematic study on EP (SACLAY)
- sulfur production
- Bath aging
- Surface brilliance
- EP mix variations
- 1 Cell tests
- Automated EP (INFN)
- Dynamic control
- Fluxgate magnetometry

## CARE and DESY efforts

- CARE
- Dry ice cleaning (DESY)
- DESY
- Understand HF outgassing from acid bath
- Quality control of acid (Henkel)
- IV curve and titration, NMR
- New HPR system design
- JLAB (IP3I)
- HPR studies
- Evaluation of cleaning methods