**BEAMLINE STABILITY WORKSHOP**

**NSLS-II, Aril 18-20, 2007**

**CONVENTIONAL FACILITIES**

**WORKING GROUP REPORT**

**John Sidarous**

**Presentations**

For the presentations materials and other details, please refer to the
BSW web site

**Presentation 1:**

NSLS2 Ground Motion and Vibration Studies; by Nick Simos

Nick has been developing a comprehensive 3-D FE model that incorporates
the SR enclosure box, SOG, with the capability of introducing vibration
sources at various locations. The model also addresses spatial wave
propagation. Nick visited APS (along with HDR) and Spring8 to take
measurement in similar operating facilities, understand the expected
performance, and collect data on forcing function from large noisy
equipments and vibration generated within the SR-EH buildings
themselves. This modeling went further than what has been done in the
past in US light sources and Nano centers. NSLS2 and Nick are to be
commended for this exceptional effort.

\- Ambient vibrations were measured, verified the suitability of NSLS2
site (20nm)

\- The model indicated the building attenuation of Ambient Vibrations
will reduce it to approx. 12nm

\- Conservative vibration input was applied to the model at several
alternate locations of Service Building and AHU. The model indicates
that at 30' distance (between AHU and SR) the SR floor vibration due to
the SB generated vibration will decay to less than 1 nm.

\- During the discussions Nick stated that the effect of reducing SR
slab thickness from 39" to 27". It shows insignificant effect on floor
vibration (\<1nm), and shows even better performance above 40Hz.

\- The measurements illustrated the effectiveness of floor isolation
joints.

\- A computer animation of noise traveling through the slabs indicates
the presence of very quiet regions on the Exp. Hall floor between
Service buildings.

\- Nick's presentation includes "Path forward" which summarizes plans
for additional measurements, modeling and assessments.

**Presentation 2:**

Data from APS Survey, March 20007; by Hal Amick of Colin Gordon

In addition to the measurements Hal and Nick took, Hal performed Hammer
test in order to assess transmissibility with distance and across
joints. The points included were on top of SR, thick SOG near SR, EH
floor, below Mech. Mezzanine.

\- The data shows that APS performs well below VC-A and NIST-A in both
the vertical and tangential directions. The slab performs even much
better in the Tangential (Axial to Beam)

\- Several peaks detected at different frequencies. The report
attributes them to local sources on the floor, or inside SR, rather than
building machinery.

\- The approach adopted by APS (implementing acoustic features in
construction and administrative controls) results in NC-64 noise with
4dba range.

**Presentation 3:**

Conventional Facilities Temperature Stability, by Chris Channing

Some aspects of this presentation are addressed by members of the
"Temperature Stability Working Group"

\- The NSLS2 team drew on the recent experience in CFN thus adopting the
latest technology, especially the controls.

\- The SR air system is independent from the rest of the space. SR will
be positively pressurized thus virtually eliminating the air
infiltration problem experienced by APS.

\- Chris assured the audience that NSLS2 selection of system design,
hardware and controls, achieving and even exceeding the target Temp.
Tolerance of +/- 0.1 Deg. is practical.

\- A discussion took place to clarify the Temp. Variation cycle.
Accelerator group stated that the +/- 0.1 Deg per hour does not
neccissate having repeated cycles every hour. The intent is that that
tolerance range should nit be exceeded in any 1 hour or shorter
periods. - The important thing is to hold the temperature at any
location to within that tolerance and that the drift of local average
temperature should be investigated.

\- Chris stated that the controls sensor drift should not exceed +/-
0.02 Deg in 2 weeks, which was judged as acceptable. The spatial
variation, i.e. from one spot to another, is not important as long there
are no significant thermal gradient across any magnet.

\- At steady state operation, after orbit has been established the loads
should not vary, except by a few Watts at corrector magnets.

\- The anticipated air changes per hour are 10. Accelerator
representatives indicated a desire for lower number of air changes to
minimize disturbances. Chris indicated that when the tunnel is closed
(operational) this will be quite possible.

\- NSLS2 intends to have no outside air makeup during operations (make
up from tempered air in EH). This will enhance temp. Stability.

**Resources and Time Frame**

With an experienced A/E on board, and Nick Simos as an in-house
vibration expert, this is not a strong concern at the moment. It is
assumed that the scope of work of the A/E will include the engineering
effort required to incorporate the adopted recommendations.

**Recommendations:**

\- The effort and approach taken by NSLS2 is commendable.

\- Follow-up on the "Path Forward" outlined in the various presentations
made throughout the workshop.

\- More validation of the assumptions of FE model, especially those
related to soil. This should be done on site using NSLS1 and
measurements at several points to get a good hold on actual decay, use
similar FEM to reproduce the measured results and validate or revise the
soil assumptions.

\- I would like to have more analysis (either numerical or measurements
to separate effect of large vibration sources (AHU and chillers) to
truly understand the building/slab/soil attenuation of such sources. In
APS, vibration from Arhus were source of complaints by EH users.

\- With newly validated assumptions, run the same FEM to perform more
parametric for slab thickness, location of Service buildings, and other
excitations.

\- At later design stage, consider adding the structural framing, actual
out-of-balance excitations from AHU and pumps.

\- Revisit the project design parameters regarding the infield service
buildings. From vibration prospective, it may be better to locate them
in the outfield (maybe incorporated into LOBs) A discussion took place,
and CFG will pursue that approach from cost/benefit approach. In either
case, even with the analysis resulting in acceptable outcome, an attempt
should be made to locate rotating equipments as far away from SR as
practically feasible.

\- A concern was expressed about the effect of the condition in the
infield, especially building column and footing deformation, effect of
berm, and daily/seasonal temperature variation, and vibration
transmission across that boundary. That particular Arch/ Structural
detail should be devedeloped and vetted very early in the process

\- The infield boundary should be analyzed by an adequate computer
modeling (heat transfer, deformation, and vibration). This should not be
a difficult task and is likely to put to rest the concerns expressed.

\- I asked about provision for space for user equipments and storage for
all. This needs to be addressed early on. That space could also be
utilized as a buffer between various equipments and SR.

\- Acoustic environment should be on the forefront early in the
engineering design. At APS, we allowed the users to install control
rooms on the floor to provide quiet (NC45) for

\- NSLS2 is to be forward leaning as far as the administrative policy of
what users could do or not do? Could they bring rotating equipments on
the floor? How about noise and vibration generated by users? Source of
utilities provided to users?.

\- Caution; a lot of vibration sources will be added with the
accelerator hardware, especially equipment and flow induced vibrations.
Need to have this considered and evaluated early on.

\- In addition to the recommendations on HVAC system made by
"Temperature Stability Workgroup", I would recommend performing a in
depth peer review by a ME from a sister facility (both now and during
Title I)

\- Use a "Computational Fluid Dynamics" CFD Model simulate the load and
Temperature within the tunnel. It was suggested to collaborate with TPS
(NSRRC) who has done similar analysis.

\- It was suggested to have uniform return air (this may not be
necessary pending CFD results). Chris indicated that he may also
consider looping the air supply ducts to allow for redundancy (for just
in case an indivuaddl AHU goes down unrepentantly)

\- It was suggested that supply air ducts be reduced from 20 to 15 to
correspond to the 15 super cells.

\- Accelerator group to confirm no significant load variation during
operations.

\- Consider shutting lights in SR during operations to reduce load and
air changes.

\- Verify that all critical and life safety systems are connected to the
Emergency Power. This issue also came in conjunction with the cryogenic
N2 system.