The Coudé Lab Environment

Boulder18 March 2009

The Coudé Lab

Air Curtain Interface

Instrument Foundations

Instrument Foundations

Air Curtain Interface

Dust Control Requirements

0.002 %/hr ≈ 264 ppm per 24 hrs

Scatter w ith Accumulation

0.0E+00

2.0E-05

4.0E-05

6.0E-05

8.0E-05

1.0E-04

1.2E-04

1.4E-04

1.6E-04

1.8E-04

1.0 1.2 1.4 1.6 1.8 2.0

Distance from Sun Center (solar radii)

Rat

io to

On-

Dis

k Irr

adia

nce

Microroughness

0.01% Coverage

1 Day (0.063%)

1 Week (0.38%)

Figure 15. The figure shows the effects of dust accumulation on the primary mirror after one day and one week, assuming the UKIRT accumulation rate of 0.002 percent per hour. [TN-0013]

… we can tolerate about … 0.3 percent total coverage…we will exceed the stray-light budget after only 132 hours (about five days). [TN-0083]

Photosphere: The scattered light from telescope and instrumentation from angles > 10 arcsec shall be 1% or less.

Cleanrooms

Class

# 0.5mmparticlesper ft3

# 5.0mmparticlesper ft3

airchangesper hour

ceilingfiltercoverage(%)

airvelocity(fpm)

max.vibration(min/s)

temp.tolerance

RHtolerance

approx.capital costper ft2

office 12-18 ? $10

100,000 100,000 650 18-30 10 $50

10,000 10,000 65 40-60 30 10 ±3.0°F ±5% $200-250

1,000 1,000 6.5 150-300 50 30-50 ±2.0°F ±5% $350-400

100 100 0.65 400-540 80-100 75-90 500 ±1.0°F ±5% ~$1200

10 10 0.065 400-540 100 75-90 250 ±0.5°F ±3% ~$3500

1 1 0.0065 540-600 100 90-100 250 ±0.3°F ±2% ~$10,000+

0.5 0.5 0.0033 540-600 100 100-110 125 ±0.1°F ±1% ~$25,000+

Cleanrooms fall under the following FED-STD-209E classifications:

Note: Dunn environment approximates Class 100,000 (ISO 7) with existing filtration in use

The Downflow Concept

Environmental Rooms

• Clean Room – has a controlled level of contamination that is specified by the number of particles per cubic meter at a specified particle size, but it also implies many other parameters.

• Environmental Room - temperature and/or humidity level is controlled at a single set condition within specified tolerances regardless of activity in the room.

• In any case - tight temperature control requires flow that is free of recirculation zones.

The Coudé Lab

END

from “The Harris Guide to Environmental Room Design”

Design Parameters•Temperature and Velocity

•Design set-point (0.5 m/s and 20 or 21 or 22 (0.5 m/s and 20 or 21 or 22 C)C)•Temperature Uniformity @ work surface (0.25(0.25 C)C)•Temperature Gradient through room (0.5(0.5CC))•Velocity (0.5 m/s @ optics)(0.5 m/s @ optics)

•Heat Loads (sensible & latent)•Design allowance (lights, ventilation, instruments, equipment, etc.)•Vagrant Loads (people, laptops, equipment?)(people, laptops, equipment?)

•Humidity•35-50% for comfort, 45% for ESD (45%(45%±5%)±5%)•Low to prevent hygroscopic adhesion of dust

•Dust Control•Filtration vs. cleaning•Contamination control (personnel, construction materials, etc.)

•Pressure Control (positive pressure) •Service Access (access to filters, etc.)•Vibration (fans, equipment locations)

CROSS FLOW mechanical packaging

Air Handling Unit

Return Air

Supply Air

CROSS FLOW results

CROSS FLOW boundary conditions

SUPPLY

RETURN

•Air properties for 3000-m

•16ea – 4’x4’ openings supplying 4 m3/s @18˚C

•16ea – 4’x4’ openings for return @ P=0 Pa

•Thermal properties set up, but never run