Minutes BWS Upgrade: Electro-Mechanical Design Meeting #15 -- 10th October 2016 --
Participants: R. Veness, F. Roncarolo, J. Emery, P. Andersson, D. Gudkov, W. Andreazza, J.L. Sirvent, C. Vulliez, A.Goldblatt
Agenda( https://indico.cern.ch/event/569140/
)
1. Progress on preparation and test of PSB prototypes:
1.1 Mechanics (D.Gudkov)
- Prototype Test program aims to schedule tests for:
- 3 Prototypes: 1x PSB, 1x Laboratory + Tank, 1 x Test-Bench with no tank
- PSB prototype ready for vacuum qualification
- PSB Installation procedure tested on laboratory
- Successful installation in <5min
- Requires the usage of a crate + 2 people
- Optical Disk status
- Glass disk + Glass sample ordered
- Holder for glass disk ready for production
- New metal samples to study with electrochemical polishing (25 samples AW-2219 + 25 samples AW-6082)
- Electrochemical polishing tests with SS under preparation.
- Scintillator + Filter Box + PMT Assembly:
- Design ready 97%
- Drawings are in CCD: PS_BWSA_0067 .. PS_BWSA_092
- Filter wheel designed by CERN and fabricated by Thorlabs
- 10 Units confirmed (2 with higher priority)
1.2 Acquisition (J.L. Sirvent)
- Filter wheel design:
- Updated design with Thorlabs standard filter holders & Opto-Sigma ND filters
- 8 holes with SM30.5 thread
- Components for 3 filter wheels have been ordered
- Optical encoder glass disk design:
- Selba is able to fabricate the disk with our required diameters (internal 70.2mm & external 192mm)
- Design has 2 tracks 20 & 40 um pitch (50% Cr. 50% Glass), and alignment references.
- 20um pitch: 32.0 +- 1.6 um resolution
- 40um pitch: 66.7 -+ 1.7um resolution
- 5 Disk ordered with 3-4 weeks delivery
- Available 7-11 Nov 2016.
- Optical sensors potential design improvement shown:
- Requires 2 new optical components in vacuum: 1 concave lens & 1 index grating 20um pitch
- Robustness to disk imperfections (Scratches, planarity...)
- Scan point ~ 500um-1mm diameter.
- Trade-off --> Quite sensitive to alignment
- W. Andrezza: Not possible to get the required tolerances mounting components on viewport.
- If metal disk is base-line this could be a potential help, If we continue with glass we can still rely on system as it is.
- Photo Multiplier tests:
- Optical bench prepared for testing: Dark box, ND Filters, Led & pulsed Laser, iris, holders...
- Tests: Linearity, Saturation, Dynamic range
- Systems to test: PMT R9880-U, MaPMT R7600U -01-M4, HPD PP0475C
- Different strategies for high dynamic range coverage under study.
- PSB YETS installation:
- Base line is only Standard PMT assembly + Custom MaPMT assembly
- If MaPMT is tested with ICECALV3, we may install digital electronics (unlikely on YETS).
1.3 Control tests of the PSB Prototypes (J.Emery)
- Discussion prior to presentation:
-
- Tests done on prototype: was it possible to move and reach nominal scans?
- It was checked if the ball bearings load changes with scans speed (tests performed at different constant speeds).
- Motor showed to behave as specifications.
- Many concerns regarding pre-loaded ceramics ball bearings :
- The load of the ball bearing is much bigger than the break nominal design.
- This type of bearings are used for maintaining high precision.
- Required to know what precision we're getting and also to know tolerance (Standard & pre-loaded Ceramics)
- Bigger clearance = easier to move but more mechanical play...
- Standard clearance ball bearings already bought for being installed.
- Proposed to check difference between these two types by testing with the calibration bench.
- 1 BWS with Standard + 1 BWS with Ceramics will be prepared for testing.
- From presentation:
-
- Unstable scan profiles because of issue with resolver.
- Trying to decouple feedback loops to regulate correctly
- Not nice profiles in terms of speed.
- Issue with the new resolver type:
- Signal shown is much weaker than previous type.
- Comparison done with PSB Proto (RO5032-452 SN:9026) VS Unmounted Rotasyn (RO5032-452 SN:9027)--> PSB proto shows 1/2 weaker signal (unknown reason: bigger gap?)
- Same effect when compared with SPS proto
- Better signal digitalization provided by electronics developed ("intelligent drive") than Dspace system.
- Ball Bearings tests:
- Scanner rotating at different constant speeds
- Torque has not linear behaviour with speed (3Nm @ nominal speed introduced by bearings)
- Clear behaviour difference respect motor TB
- Break design done for 0.5 Nm at top maximum force.
- Break would need to be re-designed and re-scaled for these ball bearings in order to provide it's functionality
- Material would need to be changed
- Break re-scaled (much longer).
- Current stabilization requires more study
2. Plan for series production: Milestones for mechanics (W.Andreazza)
- Design completed at end 2016 (including PSB,PS & SPS integration studies)
- Same kinematic unit for all instruments except fork (different lengths)
- Each machine needs its specific tank (for integration reasons).
- Some feedback missing from TE/VSC and BE/RF for design finalization.
- Design status (Smart design to minimise the # of variants):
- PS 90%
- PSB Pre-study based & design start in October (V. mounting).
- SPS Information and location known Integration study will start Oct/Nov.
- BI Goal: Manufacturing drawings ready for procurement Jan 2017.
- Procurement and fabrication:
- Critical material procurement done by BE/BI
- Order needs to be placed Easter 2017 for delivery in 12 months (2nd Q 2018).
- BWS ready for installation 1rst Q 2019
3. AOB
- In PSB the existing scanners will be kept once the new ones are installed.
- The most accurate scanners are the slow linear LHC and SPS scanners.
- Is it possible to use the SPS rotary at lower speeds? (performance needs to be checked in this cases)
- Need to get information from calibration bench (end 2016)
- Try to get measurements of repeatability + accuracy
- Also needed to check wire stress at nominal speeds PSB.
- Concerns about # of calibration benches:
- Proposed to have 2 or 3 benches for parallel commissioning/testing.
- Possible always to provide holders for BWS (no tanks) in order to simplify installation.
Topic revision: r3 - 2016-10-14
- unknown