Quantum Cascade Laser Spectrometer

Short Name or Variable Name:

QCLS

HAIS Instrument:

Yes

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this document

Manufacturer or Builder:

TABS

Description

Model:

HAIS Instrument

Measurements Provided:

CO₂, CO, CH₄, N₂O

General Description:

Note: Effective August 1, 2018, the Quantum Cascade Laser Spectrometer is no longer requestable through the NSF Lower Atmosphere Observing Facilities Deployment Pool.

There are two separate components to this instrument, both using quantum-cascade tunable infrared laser differential absorption spectroscopy. One module measures CO₂ with an accuracy of 0.1 ppm and a time response of one second. The second measures CO, CH₄, and N₂O, also with the response time of one second. The two instruments share a single aircraft rack. The instrument uses an infrared tunable quantum cascade laser. Detection is via a compact long-path cell. Two lasers are configured to measure CO, CH₄, and N₂O, at 1 Hz frequency and with very high precision (better than 0.5, 1.0, and 0.1 ppb Hz^-1/2, respectively). A second short-path cell of a new design provides high-precision CO₂ measurements (better than 0.1 ppm Hz^-1/2 ) using a third QC-laser.
- (Top left) Long-path, dual laser, CO_CH4_N2O sensor. Flight hardware with the long-path cell, dual laser assemblies, dual detectors (in one housing), etc., on the shock-mounted optical bench.
- (Top right) Assembly showing the purged pressure housing.
- (Bottom) CO₂ HAIS sensor. Flight hardware of the optical module showing (1) dual detector, (2) dual 4 cm cells, (3) QCL laser assembly.

The QCLS in a GV rack as installed for flight.

Measurement Characteristics:

Overall estimate of uncertainty: CO₂: 0.1ppm
Response time: 1s
Precision: better than 0.1ppm, 0.5, 1.0, and 0.1ppb Hz^-1/2 for, respectively, CO₂, CO, CH₄, N₂O

Calibration Methods:

in-flight calibration uses standards carried in gas cylinders

Example(s) of Measurement

Time series of QCLS measurements of CO₂ (left) and CO (right) compared to "classic" measurements (from the Harvard OMS instrument) and to the NCAR CO instrument. Also shown are the corresponding measurements of N₂O and CH₄. The sawtooth gray lines show the measurement altitude in reference to the scales on the right sides of the graphs.

Contacts

Lead Contact:

Steve Wofsy, Harvard University

Alternate Contact:

Britt Stephens

Status/Plans

Current Location:

Harvard University

Operational Status:

Decommissioned ( no longer requestable )

Data

External Deployments or Description:

All HIPPO deployments, where it was central to the experiment

EOL Deployments:

HIPPO

START08

ORCAS

Lifecycle

Date Acquired:

January, 2009

Serial Numbers

Property Tag and/or Serial Number:

Not Available

Manufacturer or Builder:

TABS

Note: Effective August 1, 2018, the Quantum Cascade Laser Spectrometer is no longer requestable through the NSF Lower Atmosphere Observing Facilities Deployment Pool.

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Manufacturer or Builder:

TABS

Note: Effective August 1, 2018, the Quantum Cascade Laser Spectrometer is no longer requestable through the NSF Lower Atmosphere Observing Facilities Deployment Pool.