COMPOSITION ? (QUALITATIVE ANALYSIS)

HOW MUCH ? (QUANTITATIVE ANALYSIS)

WHAT FORM ? (SPECIATION)

Mass Spectrometry

Topic I

Present Detector Technology – Faraday CupsPresent Detector Technology – Faraday Cups

•Gain is stable and precisely Gain is stable and precisely known (gain=1)known (gain=1)

•Bandwidth is consistent with Bandwidth is consistent with use in sector-based mass use in sector-based mass spectrometryspectrometry

•Useful for Useful for IIionion 10 10-15-15 amp amp(1 ion/sec (1 ion/sec 1.6 1.6 10 10-19-19

amps)amps)

•Implies that one needs about Implies that one needs about 6250 ions/sec for detection by 6250 ions/sec for detection by Faraday cupFaraday cup

Faraday CageCollector Electrode

Load Resistor

Out to amplifier

Out to amplifier

“FARADAY ELECTRODE”

output

High Z

Electron Multiplier DetectorElectron Multiplier Detector

Secondary Electrons

Incident Ion

Electron Multiplier DetectorElectron Multiplier DetectorD

ete

cti

on

Effi

cie

ncy

Dete

cti

on

Effi

cie

ncy

Mass (m/z)Mass (m/z)

00

Electron multiplier Electron multiplier has a gain that is has a gain that is dependent upon dependent upon the mass or kinetic the mass or kinetic energy of the energy of the incoming ion.incoming ion.

Electron Multiplier DetectorElectron Multiplier DetectorD

ete

cti

on

Effi

cie

ncy (

%)

Dete

cti

on

Effi

cie

ncy (

%)

Energy (eV)Energy (eV)

00

100100

8080

6060

4040

2020

1010 101044

101033

101022

-

h

e PtSi Photoactive Layer

Silicon Multiplexer

Focal Plane Array

Individual preampsfor each pixel

In bump

bonds

“FARADAY CUP”

RESET

36 fF

MUX

4.4 V / e--

20 e-- read noise @ 77 K

Ion SourceIon Source

Electrostatic SectorElectrostatic Sector

Magnetic SectorMagnetic Sector

Array Detector onArray Detector onFocal PlaneFocal Plane

--

++

Mattauch-Herzog MassMattauch-Herzog MassSpectrometer GeometrySpectrometer Geometry

Design Specifications

• Noise - 5 electrons read noise (highest gain)

• 39.6 microvolts / electron (highest gain)

• Well size - 80,000 e to 16,000,000 e

• 50 micron pitch

• Read rate - 1 mega sample per second into 30pfd &10kohm

• Nondestructive / Destructive Readout

“FARADAY ELECTRODE”

RESET

10 f

MUX

990 f

Gain

F

F

Detection Limit

8 IONS ! & we are still optimizing it !!

Keep tuned

2.5 electrons of read noisewith NDRO

CMS

35 lbs.75 watts

GC, PumpsMass spec.

etc.

Ion Mobility SpectrometryIon Mobility Spectrometry

Ion Mobility SpectrometerIon Mobility SpectrometerIon Mobility SpectrometerIon Mobility Spectrometer

IMS is a technique that is being employed to solve problems where portable instrumentation and ruggedness is necessary

IMS is a technique that is being employed to solve problems where portable instrumentation and ruggedness is necessary

New Instruments Demand Lower New Instruments Demand Lower Detection Limits Detection Limits

Must Operate through a Wide Range Must Operate through a Wide Range of Temperaturesof Temperatures

Must Operate at Atmospheric Must Operate at Atmospheric PressurePressure

High S/N RatioHigh S/N Ratio

New Instruments Demand Lower New Instruments Demand Lower Detection Limits Detection Limits

Must Operate through a Wide Range Must Operate through a Wide Range of Temperaturesof Temperatures

Must Operate at Atmospheric Must Operate at Atmospheric PressurePressure

High S/N RatioHigh S/N Ratio

Applications Using Ion Mobility SpectrometersApplications Using Ion Mobility SpectrometersApplications Using Ion Mobility SpectrometersApplications Using Ion Mobility Spectrometers

Field-Portable detection of Field-Portable detection of chemical warfare agentschemical warfare agents

Detection of explosives, nerve Detection of explosives, nerve agents, toxins, and other agents, toxins, and other hazardous chemicals at safety hazardous chemicals at safety inspection stations and in the inspection stations and in the environment environment

Structural Structural conformation studies of conformation studies of proteins, polymers, and proteins, polymers, and various other moleculesvarious other molecules

Ion Mobility SpectrometerIon Mobility Spectrometer

IonizationChamber Drift Region

Drift Rings

Gas Inlet

Gas Outlet

-

Electric Field

Ion Shutter FaradayPlate

Drift Gas Inlet

Chemical Identification Based Upon Ion Chemical Identification Based Upon Ion MobilityMobility

Relationship of Ion Mobility to Molecular Relationship of Ion Mobility to Molecular TermsTerms

316

eN

1m

1M

+2k

T

1 + r2 K =

Drift Velocity: vd = K E Mobility: K = d

td E

E Electric Field Strengthtd Drift Timem Ion Mass (analyte)N Number DensityT TemperatureCollision Integral

d Drift Path Lengthe Unit ChargeM Molecular Mass (drift gas)k Boltzmann-Constantr Minimum in Potential CurveCorrection Term

“FARADAY ELECTRODE”

output

High Z

“FARADAY ELECTRODE”

RESET

8 fF

MUX

New interlocking 8 ring microIMS

25pg TNT -1825VDC Emco PS, 90C 100/50 ml/min Cl-/AirFilament, inj 125C. Filters OFFResolution 84. Run a baseline noise 0.005 S/N=30Detection Limit = 2.5 pg

1-31-05

5pg TNT 95 oC 25V Injector Block 0.85AFilament, 1200 us Pulse B.C. FIRW on ( 0.9 pg Det. Lmt.)

8in.

18 in.

12 in.

Proposed Vehicle Based IMS

1200

1300

1400

1500

1600

1700

0 20 40 60 80 100 120

Time (ms)

Inte

nsi

ty (

AD

U)

e- peak

47 attograms insingle sweep

RDX

Detection Limit = 5 attograms RDX

Conclusions

• CTIA is ideal for IMS– Fast (1 MHz or higher per pixel)– Low read noise– 1000 x sensitivity improvement over current

micro-IMS device.– Expect further improvement with differential

devices and cooling.– Don’t need low secondary electron yield

coatings or exotic geometries for IMS.

Conclusions

• CTIA is ideal for IMS– Fast (1 MHz or higher per pixel)– Low read noise– 1000 x 10,000 x sensitivity improvement over

current micro-IMS device.– Expect further improvement with differential

devices and cooling.– Don’t need low secondary electron yield

coatings or exotic geometries for IMS.

Miniature Optical Bench

14mm

How do you make an optical bench that is just 14mm long?

Axsun’s Handheld Substance ID Solutions

Raman Handheld Substance Identifier Concept

Raman Probe

TEC High Power Laser Diode

TEC Spectrometer

Battery

Fiber Optics

Raman Spectral Range Dependence on Excitation

Excitation

246nm

Raman Shift (cm-1)

2000 40000

270.4nm256.5nm244.0nm

488.0nm

785.0nm

540.8nm

931.2nm

606.4nm

1144.3nm

224.3nm

980nm 1225nm 1450nm

•900-1700 nm is critical “molecular fingerprint” region for scientific research and analysis of food, pharmaceutical, chemical, and plastic products.

•Ideal NIR sensor will have high QE between 900-1700 nm, high sensitivity, high dynamic range.

NIR Spectroscopy/Imaging With Focal Plane Arrays

Photon-Processor™Extreme Low Light Level Digital Video

Imager

• Low Cost

• Patented Technology

• Camera Electronics On-chip

Day/Night Operation SXGA (1024 X 1280) Resolution Low Power <600 Mw @ 3 VDC

Photon-Processor™

Light

Photoelectrons CMOS Imager

Video Output

Photocathode

Light

Photoelectrons CMOS Imager

Video Output

Photocathode

Complete NIR Spectrometer

WavelengthReference

PowerReference

Amp

DSP processor

24-bit A/D converters

SLED source

MEMS tunable filter

PC and software

Single element InGaAs detector

Wired or wireless

Spectrometer Sample

Butterfly packages

Probe or opticsBlue lines are light, red are electrical

Reference Block Diagram

• WARM (Wavelength & Amplitude Reference Module)– Ultra stable beamsplitters tap off known quantities of light– Absolute wavelength reference provided by an integrated quartz etalon and a

miniature acetylene gas cell that are temperature controlled to 0.1oC– Amplitude reference provided by matched single element photodetectors that

divide out responses from every point of a scan

WARM (wave, amplitude- reference) Module

• Tunable laser spectrometer, in portable package

• With embedded PC and sample interface

LCD

Display

Sample interface

Tunable laser spectrometer