# Presentation: 796176

## NSLS – II  CFAC Review

**NSLS – II  CFAC Review**

**Conventional Facilities**
**Vibration Mitigation**
**Marty Fallier**
**Director for Conventional Facilities**
**National Synchrotron Light Source – II Project**
**October 18, 2006**

## Vibration Mitigation 

- Measures to be implemented in conventional design include:
- “Monolithic” slab for accelerator and experimental floor
- Slab thickness and section changes based on vibration modeling results during Title I
- Possible use of polymer admixtures for enhanced damping characteristics
- Isolation of bldg structure from tunnel and slab
- Inertial bases and isolation of  machinery
- Low flow velocity design for ducts and piping
- Limited use of duct and piping isolation to avoid conversion & transmission of  low frequency vibration
- Commissioning of equipment and systems to include alignment, balancing & vibration measurement

## Tunnel Design - Ring Building Section

## Vibration Studies 

- Vibration criteria for accelerator: < 30nm from 4 – 50 hz, PSD
- Colin Gordon Assoc. (CGA) performed site vibration evaluation as part of concept design
- “Free-field” analysis performed in June 2006
- Data taken during daytime at several locations at NSLS II site
- Initial results were spotty due to free-field measurement method
- Instruments rest on stake driven into ground
- (Ideally should be on slab in intimate contact with ground)
- Subject to wind and surface noise impacts
- Not representative of insitu-bldg performance (slab filtering/damping effect)

## Vibration Studies cont’d

- CGA returned late August 2006 and measured @ several locations:
- Night-time (inactive) CFN microscopy lab slab – simulates NSLS II mass slab effect to some degree (although closer to operating facilities)
- Night-time (inactive) exterior on lamp pole base between CFN and NSLS
- Inside NSLS near beamline x-1 during active operation
- Daytime reading at remote BNL site to see if local vibration sources are a factor
- Results:
- The site most similar to the future NSLS II – the CFN slab, met the vibration criteria except at the very lowest frequencies (<6hz).  This appeared to be due to instrument noise at the very lowest frequencies.
- The PSD performance was comparable to other world leading light source facilities (on par at lower frequencies, better  at higher frequencies)
- There are local vibration source effects which, if eliminated or reduced, could improve NSLS II vibration performance even more – these should be pursued

## Vibration Studies cont’d

- Results:
- The site most similar to the future NSLS II – the CFN slab, met the vibration criteria except at the very lowest frequencies (<6hz).  This appeared to be due to instrument noise at the very lowest frequencies.
- The PSD performance was comparable to other world leading light source facilities (on par at lower frequencies, better  at higher frequencies)
- There are local vibration source effects which, if eliminated or reduced, could improve NSLS II vibration performance even more – these should be pursued
- There are diurnal effects which, if the source is understood, may enable reduction in daytime vibration energies
- The slab effect is a significant factor and should be modeled for NSLS II given its unique annular shape

## Comparison – Results - Vertical

## Comparison – Results  - Horizontal

## Comparison-Results - Remote BNL site

## Vibration Path Forward

- Continued vibration study and modeling is required to:
- Optimize vibration resistant design vs the quantity of concrete & steel in the tunnel and experimental floor slabs to contain costs
- Identify local sources of vibration from on-site/off-site operating facilities to enable remediation (i.e. repair roads, balance machinery etc.) and optimize operating environment for NSLS II
-  Assess impacts of proposed NSLS II structures and equipment on vibration environment