Aerosol Particle Charge Conditioner

*** NEW – March 10, 2023

An attachment has been added. The document contains questions and answers related to the Challenge.

*Please note the ISC Website will be available on January 26, 2023 at 14:00 EDT

This Challenge Notice is issued under the Innovative Solutions Canada Program (ISC) Call for Proposals 003 (EN578-20ISC3). For general ISC information, Bidders can visit the ISC website.

Please refer to the Solicitation Documents which contain the process for submitting a proposal.

Steps to apply:

Step 1: read this challenge

Step 2: read the Call for Proposals

Step 3: propose your solution here

Challenge title: Aerosol Particle Charge Conditioner

Challenge sponsor: National Research Council (NRC)

Funding Mechanism: Contract

MAXIMUM CONTRACT VALUE:

Multiple contracts could result from this Challenge.

Phase 1:

• The maximum funding available for any Phase 1 contract resulting from this Challenge is : $150,000.00 CAD excluding applicable taxes, shipping, travel and living expenses, as required.
• The maximum duration for any Phase 1 contract resulting from this Challenge is up to 6 months (excluding submission of the final report).
• Estimated number of Phase 1 contracts: 2

Phase 2:

Note: Only eligible businesses that have successfully completed Phase 1 will be invited to submit a proposal for Phase 2.

• The maximum funding available for any Phase 2 contract resulting from this Challenge is : $1,000,000.00 CAD excluding applicable taxes, shipping, travel and living expenses, as required.
• The maximum duration for any Phase 2 contract resulting from this Challenge is up to 18 months (excluding submission of the final report).
• Estimated number of Phase 2 contracts: 1

This disclosure is made in good faith and does not commit Canada to award any contract for the total approximate funding. Final decisions on the number of Phase 1 and Phase 2 awards will be made by Canada on the basis of factors such as evaluation results, departmental priorities and availability of funds. Canada reserves the right to make partial awards and to negotiate project scope changes.

Note: Selected companies are eligible to receive one contract per phase per challenge.

Travel

No travel is anticipated in Phase 1. Project meetings will be conducted via video conferencing. 

Kick-off meeting

All other communication can take place by telephone, videoconference, and WebEx.

Progress review meeting(s)

Any progress review meetings will be conducted by videoconference or teleconference. 

Final review meeting

All other communication can take place by telephone, videoconference, and WebEx.

Challenge Statement Summary

The National Research Council (NRC) is seeking an aerosol particle charge conditioner that will induce a unipolar or bipolar charge distribution on a population of aerosol particles that is stable, repeatable, reliable, and transportable, with low losses and high charging efficiency.

Challenge Statement

The National Research Council's (NRC's) Metrology Research Centre (METRO) has extensive experience with aerosol measurements. Aerosol measurements have important applications in disease transmission, air quality monitoring, climate forcing, and nanomaterial synthesis. METRO measures aerosols in these fields and is seeking to reduce the associated sizable measurement uncertainties. METRO uses either unipolar or bipolar aerosol particle charging devices in several applications where the particles must be electrically charged prior to passing through their instruments. The measurement systems include Differential Mobility Analysing System (DMAS), the CPMA-Electrometer Reference Mass Standard (CERMS) used for calibrating particle mass concentration instruments to a traceable standard, and the Particle Filtration Efficiency Measurement System (PFEMS). In DMAS and CERMS, particles are first electrically charged, and their motion in an electrostatic field is used to classify and quantify particle properties. The particle charging stage, comprising a charge conditioner, is an implicit source of uncertainty and a limiting factor in detection limits and time resolution of the measurement systems. Innovations focused on improving the charging of aerosol particles would overcome these limitations, which are critical for improving the time resolution, accuracy and stability of these measurement systems, ultimately leading to improved techniques for measuring aerosol properties.

Desired outcomes and considerations

Essential (mandatory) Outcomes

The proposed solution must:

1. Produce both a unipolar and a bipolar charge distribution (not simultaneously, but switchable).
2. Produce known charge distributions that are primarily correlated with particle mobility diameter. For spherical particles, this requires a mean charge of unipolar charge distribution within +/- 40% of the expected value and a mean charge of bipolar charge distribution within +/- 30% of the expected value.
3. Not generate ozone or other undesirable gas species or aerosols.
4. Have low particle losses, with transmission efficiencies (at a volumetric flow rate of 1.5 liters per minute which is typical of aerosol instrumentation) greater than 75% for particles with mobility diameters from 10 nm to 25 nm, and greater than 90% for particles with mobility diameters from 25 nm to 500 nm.
5. Have a residence time that is less than 20 seconds for greater than 95% of the particles and for a volumetric flow rate of 1.5 litres per minute which is typical of aerosol instrumentation.
6. Produce a unipolar charge distribution with extrinsic charging efficiency by total particle mass greater than 80% (for typical soot from a laboratory source that has a mobility size distribution with a geometric mean diameter of 200 nm+/-20% and a geometric standard deviation of 1.7+/-20%).
7. Not use radioactive sources with high activity that require user licences that are limited to specific locations.
8. Have a compact volume of less than 10 litres and easily transportable.
    

Additional Outcomes

The proposed solution should:

1. Control the mean elemental charges per particle for a particle with a mobility diameter of 200 nm to between -4 and 0 when produced by negative unipolar charging and between 0 and 4 when produced by positive unipolar charging.
2. Be switchable between positive unipolar and negative unipolar as well as bipolar charge distributions.
3. Produce a known bipolar charge distribution for a range of high volumetric flow rates between 1.5 to 5.0 litres per minute.
4. Produce charge distributions that are stable over 8 hours, such that for spherical particles the mean charge of the produced bipolar charge distribution is within +/- 30% of the expected value and the mean charge of the produced unipolar charge distribution is within +/- 40% of the expected value.
5. Produce a known charge distribution that is primarily a function of particle mobility diameter and is largely insensitive to initial charge distribution, such that for spherical particles with a mobility diameter of 200 nm regardless of their initial elemental charge state between -2 and 2, the mean charge of final bipolar charge distribution is within +/- 30% of the expected value and the mean charge of final unipolar charge distribution is within +/- 40% of the expected value.
6. Have low particle losses, with transmission efficiencies (at a volumetric flow rate of 1.5 liters per minute which is typical of aerosol instrumentation) greater than 85% for particles with mobility diameters from 10 nm to 25 nm, and greater than 95% for particles with mobility diameters from 25 nm to 500 nm.
    

Background and Context

METRO’s experimental techniques require the aerosol particles to have a charge, either a neutral charge distribution as produced by a bipolar charger, or a strong unipolar charge distribution. METRO has a strong understanding of the theory for charging, the limitations of current charging devices, and METRO uses approaches to assess the additional uncertainty introduced by the limitations of the existing charging methods. To achieve their research objectives, there is a need to reduce the uncertainties associated with the aerosol measurements, as well as extend the range of measurements.

A product that meets the essential outcomes would revolutionize the aerosol measurement field. It would allow measurements that are not currently feasible, and dramatically reduce the uncertainties associated with aerosol measurements. The CERMS system is limited by the throughput of the unipolar charger that is currently in use, which has a penetration of ~40%. This limits the range of concentrations over which the mass concentration instruments can be calibrated, due to the loss of over half of the particles. The DMAS system is limited by the locations to which the system can be transported with Kr-85 radioactive chargers (not useful for field measurement studies) and the expensive soft x-ray sources which have a short lifetime and a charging efficiency that has greater uncertainty in the charge distribution.

Canada has the potential to become the world leader in providing the best and most flexible aerosol particle charge conditioner. Aerosols are a concern from both the climate forcing and human health perspectives, as well as air quality (indoor and outdoor). Having this improved product will result in higher quality aerosol measurements, not only for NRC, but also for research laboratories and monitoring sites around the globe. The data with reduced uncertainty produced by instruments using this improved aerosol particle charge conditioner will be more valuable in driving evidence-based decision making by policy makers. In addition to the identified CERMS, DMAS, and PFEMS instruments, there is potential for combining this innovative product with several other aerosol measurement techniques, including fast mobility particle sizing, and low cost and medium cost unipolar charge-based sensors. Further, there may be applications in production of engineered nanoparticles, such as with flame spray pyrolysis, and in other measurement techniques, such as the particle charging and precipitation stage for thermal desorption chemical ionization mass spectrometry (TDCIMS). NRC METRO believes that the solution developed in this challenge will result in a commercially viable product that is vastly superior to anything in the market, in addition to meeting METRO’s specific requirements.

ENQUIRIES

All enquiries must be submitted in writing to TPSGC.SIC-ISC.PWGSC@tpsgc-pwgsc.gc.ca no later than ten calendar days before the Challenge Notice closing date. Enquiries received after that time may not be answered.

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