Cosmic Dust Experiment (CDE) Science and Calibration

1
Cosmic Dust Experiment (CDE)Science and
Calibration

• David James
• University of Colorado/LASP
• 303-492-5208
• david.james_at_lasp.colorado.edu

2
Science Goals
Monitor the cosmic dust flux variability CDE
measures dust flux using an impact
detector. Measurement at S/C is directly related
to dust input to the mesosphere.
3
Dust Detection using PVDF
Depolarization induced current
PVDF Film
Al/Ni Contacts
4
Calibration and Validation Plan

• Calibration is performed in two steps
• Electronics (DN to charge)
• Performed at LASP 9/16-9/20
• PVDF Detectors (Charge to mass, given velocity)
• SDC calibration with dust accelerator in
  Heidelberg, Germany is complete
• Proposed CDE calibration in early 2006

5
E-box Calibration

• Calibration of Electronics was performed at LASP
  before (abbreviated) and after the environmental
  (full) testing
• Tested full dynamic range of each signal chain
  104-1010e charges at 21 individual values (100
  events at each of the 21 values injected
  externally).
• Tested over full range of E-box temperatures (-26
  to 50oC)
• Full calibration at -26, 0, 15, 30, 50C
• Pre-Environmental Calibration at 20oC
• Repeated for all 14 channels
• Total Calibration generated 14 x 5 x 21 1476
  data sets of 100 hits.

6
Calibration Setup External Charge Injection
Environmental Chamber
Injection Circuit to Simulate Detector Signal
Data Collection
7
Sample CDE Calibration Curves
8
Simpson-Tuzzolino Curve
9
CDE will maximize impact rates
CDE detector area 0.1 m2 300 hits/day _at_ 0.1 ?m
threshold 3 hits/day _at_ 1.0 ?m threshold Science
requirement 100 hits/week ? 0.7 ?m threshold
mass
10
PVDF Detectors
100 hits/day
15 km/s
To meet science requirement of 100 hits/week must
have a noise floor of 106 electrons.
10
13
100 hits/week on 0.1 m2
11
CDE Noise Characterization
Noise floor well below required 106
electrons. CDE satisfies its science requirements!
9105 e level
12
Calibration Summary

• Charge injection calibration has been completed
  and is ready for integration into ground
  processing software
• Determination of noise floor via zero threshold
  noise collection verifies that CDE meets science
  requirements
• CDE is ready to ship and meets science
  requirements