Building Holodec 2

Building
HOLODEC 2
ASP Research Review

Outline
• Project Summary
• Optical Design
• Mechanical Design
• Hologram Processing Code Design

HOLODEC 2
Project Summary
Description
Science Goals
Timeline

HIAPER Gulfstream GV
C-130 Hercules Q
HOLODEC 2 (Holographic Detector for Clouds 2)
is an airborne instrument that measures the size,
shape, and relative 3D position of cloud particles in a
local sample volume using digital in-line holography.

HOLODEC 1

HOLODEC 2
Principal Science Goals

x 10
Relative Lengths
The HOLODEC 2 has a
sample volume of 15.6 cm 3 or:
14.6 x 9.74 x 110 mm
The FSSP sample volume size
to obtain a 15.6 cm 3 is
Relative Crosssections
approximately:
2.5 x 0.1 x 62300 mm

HOLODEC 2
Principal Science Goals
• Determine the variability of local size
distributions of cloud particles of ~5 μm
extent and larger.
• Measure how strongly cloud particles
cluster on sub-cm scales due to
turbulence, mixing and entrainment of
clouds.

HOLODEC 2
Principal Science Goals
• Examine the spatial distribution and
partitioning of cloud ice and liquid water
particles in mixed-phase regions of cloud
on sub-cm scales.
• Measure the size distribution of small-ice
particles after rejecting shards of
shattered ice crystals that tend to cluster
in particular regions of the threedimensional
sample volume.

HOLODEC 2
Timeline so far
• March 2008: Project proposed to MAC.
• April 2008: EOL funds project.
• May 2008: Optical system design begins.
• June 2008: Camera and laser arrive.
• October 2008: Custom lenses arrive
• November 2008: Mechanical design of
project begins.
• January 2009: ASP and EOL fund rest of
project.

HOLODEC 2
Timeline to come
• Feb 2009: Complete optical system test.
Complete mechanical design and begin
fabrication of instrument body. Model flow
around proposed instrument head design.
• April to May 2009: Finish instrument
fabrication, test whole system, certify for
flight on HIAPER.
• July 1-15, 2009: Test flights during HEFT-09.
• Fall 2009: Process test flight holograms and
analyze results.

Optical Design

Optical Design
• Design allows for temperature range of -60 to +35
C.
• Alignment requirements are typically less than
~50 to 200 μm decenter and ~0.1 to 0.2 degree tilt.
• Tube must be pressurized to ~1 atm dry nitrogen.

Mechanical Design

Mechanical Design
Constraints For Probe
• Aircraft Certification Requirements
• Weighs less than 25 pounds (not counting can).
• Less than 50 square inches frontal cross section.
• No permanent deformation from 100 pounds force
in any direction on probe arms and tips.
• Symmetric such that aerodynamic drag does not
induce a significant torque.
• Center of gravity well inside PMS can.

Mechanical Design
Constraints on Probe
• Science Constraints
• Desire 14 cm or ~5.5 in between windows.
• Need optics and windows clean and dry even in
freezing cloud conditions.
• Need passage for Gigabit ethernet connection.
• Desire aerodynamic shape such that natural
condition of cloud particles is minimally
changed at the sample volume by the probe and
aircraft speeding by at 225 m s -1 .

Mechanical Design
Electronics
Laser
Box
Camera
Turning
Mirror
Camera Side
Lens System

Mechanical Design
Fiberglass
Shroud

Hologram Processing
Code Design

Hologram Processing
Code Design
• GPU hologram reconstruction has
proven to be order 25 times faster than
reconstruction on a comparable CPU,
but a CPU still necessary for postreconstruction
processing.
• Reconstruction to be run on NCSA
Lincoln Supercomputer through the
TeraGrid project.

Building
HOLODEC 2
Thank you and Any Questions
Onward Ever Onward