PC5E-0330— For easy measurements of work function and ionization potential —Photoemission Yield
Spectroscopy in Air (PYSA)

Lineup features a new compact model with the same ease-of-use
and two Pro models incorporating frequently requested functions!

AC-2S Series
AC-2S / AC-2S Pro α / AC-2S Pro β

CE Marking (pending)
UL (pending)More compact while retaining same ease-of-use!
Three new models, including basic type andpro-use types!

AC-2S Series
AC-2S / AC-2S Pro α / AC-2S Pro β

The AC-2S Series comprises three types:
For general analysis

For materials development

For device development

AC-2S

AC-2S Pro α

AC-2S Pro β

Basic model featuring reduced size andweight that retains the same all-round
functionality. Offers improved ease ofuse with new multi-point measurement
and repeated measurement functions.

Capable of high sensitivity, highresolution measurements for low work
function materials and localized levels
within band gaps.
Also capable of high-temperature andfilm thickness measurement.

Capable of micro spot work function
measurements—for example, formicroscopic pattern processed
locations.
Also capable of high-temperature andfilm thickness measurement.

AC-2S Series Features■

Refined ease-of-use
Completely updated measurement and analysis software for improved ease-of-use. (Also supports AC-2/AC-3/AC-5 data
importing and analysis.)■

Improved work efficiency with multi-point measurement function
Capable of multi-point measurements for up to 4 points. Helps improve work efficiency.

■

Repeated measurement function
Features newly-added repeated measurement function to reduce operator workloads.

■

Compact and lightweight
Significantly smaller dimensions compared to previous models (21 % reduced width, 38 % reduced weight)* Comparison of AC-2S against previous model (Pro models differ.)

Inspiration,Innovation,
Evolution
The AC Series is used widely in universities and research facilities around the world.
Above 2,000 related articles have been published on scientific journals.
Now we’ve added new features to meet the needs of researchers, for further ease-ofuse refinements.
The AC-2S Series will create new value for users and around the world.

What is the AC Series?
Allows easy measurement of work function and ionization potential in air(Measurement time: approx. 5 mins*)
Eliminates need for vacuum; samples can be easily inserted and removed, reducing measurement time.
* Measuring conditions: Measurement energy scanning range 4.2 - 6.2 eV, 0.1 eV steps, with 5 s count time per step

Measurements with high repeatability
Detects minute photoemission levels by subjecting samples to low intensity UV radiation. This minimizes damage to samples and assures highmeasurement repeatability.

AC Series Measuring Principle

E = hν = h・c/λ(h: Planck constant, ν: frequency of light, c: speed of light,
λ: wavelength)
Increasing UV energy makes it possible to obtain the photoemission
threshold energy (work function*1 and ionization potential*2) as shownon the measurement application screen to the right.
*1 Photoemission threshold energy for metals*2 Photoemission threshold energy for semiconductors

Controller
Opencounter

Optical fiber

PC

ElectronSample
Sample stage

X stage

System configuration diagram
Square root of photoemission yield

Ultraviolet light emitted from a UV lamp undergoes wavelength (energy)
selection in a spectrometer before being focused on the surface of asample placed on the sample stage. An open counter (electron countingdevice) counts electrons discharged by the photoelectric effect(phenomenon in which electrons are discharged from material surface
when the material absorbs light). The wavelength λ of the ultraviolet
light is converted into light energy E by the following equation:

SpectrometerUV lamp40

Threshold energy⇒Ionization potential⇒Work function

3020
100

4.5

5.0
5.5
UV energy (eV)：Plotted points selected for ground level calculation：Non-selected points：Plotted points selected for regression line calculation

Measurement application screen

6.0Function availability table
Function

AC-2SAC-2S Pro α

AC-2S Pro β

Multi-point measurement

●

●

●

Repeated measurement

●

●

●

High-temperature measurement－●●Film thickness measurement

－

●

●

Long-life light source－●●

Low-energy measurement－●－High UV intensity measurement－●－Micro spot measurement－－●

Consumable part replacement notification

●

●

●

Exterior drawings
AC-2S Pro α / AC-2S Pro βSide (DC connection side)

480

450

Front

Side (DC connection side)

623

450

317

317

Front

Optical fiber connector

LDLS power supply
Optical fiber connector(integral with main unit)

Power switch

Power switch

Side (LC connection side)

Front

Side (LC connection side)

Front

450465450465（35※）
Pro β only200360

163360Measuring unit (DC)Light source unit (LC)

AC-2S

Optical fiber connector

Sample door

Optical fiber connector
External lead (heater wire)
Connect to temperature controller

Sample door Temperaturecontroller
External lead (thermocouple wire)
Connect to temperature controller

Configuration diagram

Installation/Dimensions

Overview

Product configuration
AC-2S

AC-2S Pro α / AC-2S Pro β

The product consists of the light source unit (LC),measuring unit (DC), and PC used for measurement.
Dry compressed air* must be supplied via the dry air inlet
during measurement.

The product consists of the light source unit (LC), measuring
unit (DC), laser-driven light source (LDLS) power supply,
temperature controller, and PC used for measurement.
Dry compressed air* must be supplied via the dry air inlet
during measurement.

* 0.1 - 0.2 MPa, 0.5 L/min (measurement), 2.0 L/min (purging)*	 Separate conditions apply to the air supply. We recommend an optional compressor(sold separately). (Contact Riken Keiki for more information.)・Width: Approx. 1,100 mm (LC + optical fiber + DC)
・Depth: Approx. 600 mm (LC/DC + rear cables)

Power supply cable
RS-232C cable
USB cable

AC power supplycable

LC
Optical fiberDC* 0.1 - 0.2 MPa, 0.5 L/min (measurement), 2.0 L/min (purging)*	 Separate conditions apply to the air supply. We recommend an optional compressor(sold separately). (Contact Riken Keiki for more information.)・Width: Approx. 1,400 mm (LDLS power supply + optical fiber+ DC + temperature controller)
・Depth: Approx. 600 mm (LC/DC + rear cables)

Power supply cable

Dry air inlet(0.1 - 0.2 MPa)

RS-232C cable
USB cable
AC power supply
cable LDLS power supply
AC power supply
cableLC
Optical fiberDC

Dry air inlet(0.1 - 0.2 MPa)

Temperature
controller

AC power supplycableExplanation of AC-2S Pro Functions
Common for both AC-2S Pro α / AC-2S Pro β(Visualizing temperature-inducedchanges in measurement samples)

Measurement examples:
Catalysts, organic light-emitting
diode functional materials,organicsolar cell functional materials, fuelcell electrode catalysts, all-solid
battery electrodes, etc.
Example measurements at room temperature andhigh temperature● Room temperature (23.8 °C)● High temperature (100 °C)

Sample 1: Substance for which measurement results
remain unchanged even when temperatures change
30

Sample 2: Substance for which measurement resultschange when temperatures change
30

2520
15
10
50
3.4

3.8

4.2

4.6

5.0

5.4 5.8

6.2

20
15
10
50
3.4

3.8

4.2

4.6

5.0

5.4 5.8

6.2

UV energy (eV)UV energy (eV)Previous
model:

Long-life light sourceMeasurement not possible
if photoemission is low

Compatible even with materials
with low photoemission

Service lifeapprox. 1,500 hours

Service life approx. 10,000 hours

Previousmodel:

Uses laser-driven light source (LDLS)

Previous model: Down to 3.4 eV
AC-2S Pro α(Measurement not possible with anode materials
below 3.4 eV)■ Low-energy capability
Square root of photoemission yield

Measurement examples:
Organic light-emitting diode anodematerials, organic solar cell anodematerials
Measurement example using
low-energy capability
Example measurement sample:
Organic light-emitting diode anodematerial

302520151050
3.4 3.8 4.2 4.6 5.0 5.4

Capable of measuring from 2.0 eV(anode measurement possible)

UV energy (eV)3025201510502.02.4

2.8 3.2

3.6 4.0

UV energy (eV)Sufficient measurement data cannot be
obtained due to inability to measure
below 3.4 eV.

■

25

Film thickness measurement

Measurement examples:
Component surface coating
thickness measurement, etc.
■

Can be set up to 100 °C

Square root of photoemission yield■

Previous model: Room temperature only

Square root of photoemission yieldHigh-temperaturemeasurement

Square root of photoemission yield■

Measurements can be obtained due tolow-energy capability down to 2.0 eV.

High UV intensity capability

Measurement examples:Research on charging characteristics of tonerand other substances, surface concentration
measurements of additives, etc.

Previous model: 500 nW

UV intensity: above 2500 nW

Previous model: 4 mm × 4 mm

0.4 mm × 0.4 mm

AC-2S Pro β■ Micro spot measurement
Measurement examples:
Measurement of contamination/oxidation ofelectrodesand minute electrical components onPCBs, etc.
Example of measurement using micro spotmeasurement capability(Example of measurement of area of interest
consisting of nine 1 mm square objects in a row )Need to measure only one of nine areas of interest

Incident
UV spot

Area of interest cannot be measured
because the irradiation spot is too large.

Incident
UV spot

Micro spot (0.4 mm × 0.4 mm square) enables
measurement of just the area of interest.

AC-2S Series specifications
Model

AC-2S

Measuring principle

AC-2S Pro α

AC-2S Pro β

Photoemission yield spectroscopy in air (PYSA) (Detector: Low-energy electron count method)

Measurement energy
scanning range
Repeatability(standard deviation)

3.4 - 6.2 eV (364 - 200 nm)

2.0 - 6.2 eV (620 - 200 nm)

3.4 - 6.2 eV (364 - 200 nm)

Work function 0.02 eV (sample: Au plate)Standard time required for work function measurement: Approx. 5 minutes*

Measurement time

* For measurement energy scanning range: 4.2 - 6.2 eV, step: 0.1 eV, count time: 5 s per step

Maximum count rate
(CPS: Electron count per second)

4,000 cps

UV lamp

Deuterium (D2) lamp

Laser-driven light source (LDLS)

Minimum light intensity

Up to 1.0 nW (at 5.9 eV)

Up to 5.0 nW (at 5.9 eV)

Up to 1.0 nW (at 5.9 eV)Maximum light intensity

500 nW or higher (at 5.9 eV)

2,500 nW or higher (at 5.9 eV)

200 nW or higher (at 5.9 eV)

Up to 4 × 4 mm

Up to 4 × 4 mm

Up to 0.4 × 0.4 mm2

UV spot size

22Spectrometer

Grating-type monochromator

Sample size

50 mm×50 mm (max.), thickness 10 mm (max.)

Sample stage size

115 mm × 122 mm

Multi-point measurement
function
Operating temperature/humidity range

Power source

Up to 4 points (automatic measurement)
15 °C - 35 °C (no sudden changes), up to 60 % RH (no condensation)

100 - 240 V AC, 50/60 Hz, 5 A (max.)

WeightMain unit:
100 - 240 V AC, 50/60 Hz, 5 A (max.)
LDLS (AC adapter):
100 - 240 V AC, 50/60 Hz, 2.5 A
LDLS (main unit):
12 V DC, 120 W
Temperature controller: 100 V AC (±10 %), 50/60 Hz, 1 A (max.)

0.1 - 0.2 MPa, 0.5 L/min (measurement), 2.0 L/min (purging)*

Dry compressed air supply
conditions

External dimensions

120 mm × 122 mm heated sample stage 120 mm × 122 mm heated sample stage* Separate conditions apply to the air supply. We recommend an optional compressor (sold separately).
(Contact Riken Keiki for more information.)

LC (light source unit):
Approx. 480 (W) × 317 mm (H) × 450 mm (D)DC (measuring unit):
Approx. 465 (W) × 360 mm (H) × 450 mm (D)AC-2S LC (light source unit):
Approx. 25 kg
AC-2S DC (measuring unit):
Approx. 31 kg

Accessories
・ Display・ PC・ Power supply cable (for LC)
・ Power supply cable (LC-DC)・ Adapter plug
(3-pin → 2-pin + ground wire)* AC-2S: ×1, Pro α/β: ×3・ USB interface cable (PC-LC)
・ RS-232C interface cable (LC-DC)・ Detector
・ Optical fiber

LC (light source unit)*: Approx. 623 (W) × 317 mm (H) × 450 mm (D)DC (measuring unit):
Approx. 465 (W) × 360 mm (H) × 450 mm (D)Temperature controller: Approx. 200 (W) × 163 mm (H) × 150 mm (D)* The LDLS power supply is housed in the LC (light source unit).

AC-2S LC (light source unit): Approx. 30 kg
AC-2S DC (measuring unit): Approx. 31 kg
Temperature controller:
Approx. 5 kg・ Accessory sample set
・ Tweezers
・ Measurement/analysis/
data conversion software (CD- ROM)

Optional accessories(sold separately)・ Compressor (with dry air generator)
・ Tray for powder samples(1.0 mm deep)・ Tray for powder samples (0.5 mmdeep)・ Optical fiber protective acrylic cover・ Different diameter union joint(for dry air)・ Detector (for replacement)
・ Optical fiber (for AC-2S and Pro α)
・ Optical fiber (for Pro β)
・ D2 lamp (for AC-2S)・ Ozone filter

Distributed by:
2 -7-6 Azusawa, Itabashi-ku, Tokyo 174 - 8744, Japan

Phone : +81-3-3966-1113
Telefax : +81-3-3558-9110
E-mail : intdept@rikenkeiki.co.jp
Web : https://www.rikenkeiki.co.jp/english* The contents described in this catalog are

subject to change without notice according
to the performance improvement.

Printed in Japan PC5E-0330-210700 T