Jasco J-810 Hardware/function Manual

MODEL J-810

SPECTROPOLARIMETER

Hardware/Function Manual

JASCO Corporation

P/N: 0302-0407A March 1999

Safety Cautions

Correct operation and scheduled maintenance are essential for safe use
of the instrument. Read the safety cautions in this manual and fully
understand them before operation.
″WARNING″, ″CAUTION″ and ″Note″ are used throughout this manual
to call operator′s attention to safety.

(1) Meanings of safety notations

WARNING : Failure to comply with this involves the possibility of death

or serious personal injury. Serious personal injury means
loss of sight, injury, burn (high temperature, low
temperature), electric shock, fracture, intoxication, etc.
which can cause sequel or require hospitalization or long­term treatment at hospital.

CAUTION : Failure to comply with this involves the possibility of minor

personal injury or physical damage. Minor personal injury
means injury that does not require hospitalization or long­term treatment, and physical damage means damage to the
instrument itself or damage to objects other than the
instrument, such as buildings, properties, etc. (extended
damage).

Note : This contains care to be taken during operation and

information that will be helpful in operation.

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(2) Location of Warning Labels

The instrument is labeled with the following warnings. Use care not to damage or
tear the labels. Should the labels be stained or torn, contact your local JASCO
distributor with its part number.

1) WARNINGS! Handling the Xenon Lamp (①of Fig. 1)

Part number：0822-0127A

. The xenon lamp is made of quartz glass and is filled with high-pressure gas (5 to 10

atm. pressure, about four times when the lamp is lit).

Twisting, bending or impact can burst the lamp, causing danger with glass

fragments. Never open the lid of the light source unit if the lamp is lit or hot.

. When handling the xenon lamp, wear protective clothing such as a thick, long-

sleeved shirt, a mask, thick gloves, etc.

. Before replacing the xenon lamp, turn the lamp off and allow it to cool for about 30

minutes.

When replacing the xenon lamp, be careful not to give an impact to the lamp.

Never twist the lamp by holding it at both ends.

. Do not mistake the mounting direction (polarity) of the lamp. The cathode will be

damaged if the lamp is mounted incorrectly, rendering the lamp inoperable.
. Do not touch the glass portion of the xenon lamp with bare skin.
. If the glass portion of the xenon lamp is contaminated, wipe it with clean gauze

moistened with alcohol.
. After removal and before disposal, place the xenon lamp in its case, and store the

case in a safe place. If the case is not available, carefully wrap the lamp in

foamed plastic or other protective wrapping, and store it in a same place.
. When disposing of the xenon lamp, carefully wrap it in a cloth, smash it with a

hammer, and dispose of it as hazardous material.
WARNING! Fuse Rating (②in Fig. 1)

Part number：0822-0102A

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Use only fuses of the designated rating to protect both the operator and the
equipment from fire and other hazards. When replacing the fuse, turn OFF the ″
Power″ switch and unplug the power cable from the outlet to avoid electric shock.

WARNING! Grounding (③in Fig. 1)

Part number：0822-0109A

If the instrument is operated without being grounded properly, the operator may be
subjected to electric shock. Correctly ground the instrument using the grounding
terminal on the switchboard. Do not use gas or water pipes for grounding, because
these pipes are often made of non-conductive material.

150W Light Source, Small Sample Chamber

2

3

450W Light Source, Large Sample Chamber

1

1

2

3

Fig. 1

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Introduction

This manual is intended to serve as a guide for using the Model J-810
spectropolarimeter, both for experienced and first-time operators.
Prior to operating the instrument, the operator should carefully read and thoroughly

understand the contents of these manuals. In addition, the ″Measurement″,

″Analysis″ and ″ CD-ORD Measurement Method″ instruction manuals should be

understood in full. These three manuals should be kept at your hand at all time
during operation of the instrument. After operation, keep these manuals in your file.
Should the manuals be lost, contact your local JASCO distributor for an additional
copy.
Installation Requirements
Install the instrument in a location where the following conditions are satisfied. The
instrument should be installed in a room that is maintained at a constant temperature
and humidity, because the spectropolarimeter is sensitive to atmosphere fluctuations.

. Room temperature 20 ±5°C
. Humidity lower than 70%
. Not exposed to direct sunlight
. Not in the proximity of harmful or corrosive gas
. Not exposed to a high-intensity light source
. Not in the direct path of air currents emanating from air conditioners or other

equipment
. Relatively free of vibration
. Not in the proximity of a high-intensity magnetic or electromagnetic field

. For the 450W light source, within the proximity of a water supply (flow rate : 2 λ

/min, pressure : 0.5～2.0 kg/cm2). Cooling water piping : 10 m in length, inside

diameter : 12 mm

Note: Do not use water at more than 2.0 kg / cm2 pressure.

. Within the proximity of equipment that supplies nitrogen gas. (flow rate : more

than 3 λ/min). Nitrogen gas tube : 3 m in length, inside diameter : 9.5 mm.
. Within the proximity of nitrogen gas ventilator.

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Contents

1. Overview and Specifications .........................................................1

1.1 Overview................................................................................................. 1

1.1.1 Principles of operation ...................................................................... 1

1.1.2 Optical system .................................................................................. 2

1.1.3 Electrical system............................................................................... 3

1.2 Specifications.......................................................................................... 4

2. Unpacking and Installation ............................................................7

2.1 Unpacking............................................................................................... 7

2.2 Installation Requirements ....................................................................... 7

2.3 Reassembly ............................................................................................ 8

2.3.1 Removing the cushion from the main unit......................................... 8

2.3.2 Installing the modulation element ..................................................... 9

2.3.3 Installation the detector unit ............................................................ 10

2.3.4 Connecting the cables and tubes.................................................... 11

3. Names of Functions of Components ...........................................14

3.1 Overall View.......................................................................................... 14

3.2 Panels................................................................................................... 17

3.3 Sample Chamber .................................................................................. 20

3.4 Detector Unit......................................................................................... 22

4. MAINTENANCE ..........................................................................23

4.1 Light Source Check and Replacement.................................................. 23

4.2 Energy Check ....................................................................................... 25

4.3 Wavelength Accuracy Check and Adjustment ...................................... 27

4.4 CD Scale Check and Adjustment.......................................................... 28

4.5 Test Signal Check ................................................................................. 30

5. TROUBLESHOOTING ................................................................31

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π

I

I

1. Overview and Specifications

1.1 Overview

1.1.1 Principles of operation

When linearly-polarized light passes through an optically-active substance, its two
circularly-polarized components (right and left circularly-polarized beams of light) travel
at different speeds, and are absorbed in differing degrees by the substance. Thus, the
light passing through the substance is elliptically polarized, and the substance is said to

have ″Circular Dichroism (CD)″. The magnitude of circular dichroism is usually
expressed in terms of molecular elliptically [θ], which is determined according to the

following formula :

4500

θ

=−

where, εL and ε

R

polarized beams of light. The difference (∆ε) between εL and ε

the following formula :

εεε

RL

[]

θ

=

4500

LC

π

In equation (2) and (3), L represents the thickness (cm) of the absorbing layer, and C
represents the molar concentration, I

left circularly-polarized beams of light, respectively, after passing through the substance.
Theoretically, the molecular ellipticity can be derived using equation (3). However, in

practice, determining [θ] with a high degree of accuracy is very difficult using equation

(3), because the value of IR.IL is nearly 1. To avoid this difficulty, we substitute the
following quantities.

1

()

2

S

=−

RL

(5)

Since S/2

Ι

is less than 1, equation (3) can be re-expressed as follows, by substituting

A

the expressions from equations (4) and (5) :

εε

LR e

10( ) log

(1)

are the molecular extinction coefficients for the right and left circularly-

is determined using

R





1

log

=−=∆

LC

log10log

e

III +=

(4)

LRA

I

R





10




10




(2)





I

L







I

R



(3)



I

L



and IL represent the intensities of the right and

R

1

S



+

1

4500

[]

=

θ

LC

π

e




log10log

10



−

1







I

2

A




S



(6)

I

2

A



=

4500

LC

π



S



e

log10log



I

A






e

10




Thus, the ratio between IA and S can be approximated with an accuracy sufficient for
practical application.

Given that EA and ES represent the output voltages of the photomultiplier tubes
corresponding to light intensities IA and S respectively, S/IA = ES/EA. By substituting
this expression, equation (6) can be expressed as follows.



4500

[]

θ

= e

π

LC

E

S



e 10

log10log



E

A






(7)




Here, if ES can be amplified independently of EA, equation (7) can be expressed as
follows.



4500

[]

=

θ





LC

π











10log

e











GE



S







E



A



log

e



10

(8)



G



where G represents the amplification factor of ES. Since the value ESG can be brought

very close to the value of E

by choosing an appropriate value for G, [θ] can be

A

determined with a high degree of accuracy.

1.1.2 Optical system

Fig. 1.1 shows the optical system of the Model J-810 spectropolarimeter.

Ｍ

0

Ｐ

O-ray

E-ray

Ｓ

２

Ｓ

１

Ｓ

３

Ｐ

１

２

Ｌ Ｆ CDM

Ｍ

Ｍ

SH

２

３

ＰＭ

Ｍ

LS

1

Ｍ

４

Ｍ

５

M0, M1, Mp, M2 ～ M5 : Mirrors LS : Light source

～ S3 : Slits P1 : First prism (horizontal optical axis)

S

1

P

: Second prism (vertical optical axis) O-ray : Ordinary ray

2

E-ray : Extraordinary ray L : Lens
F : Filter CDM : Modulator
SH : Shutter PM : Photomultiplier tube

Fig. 1.1 Block diagram of optical system

2

A xenon lamp is used as the light source. The light emitted from the xenon lamp is
converged by the M1 mirror into the S1 entrance slit. The optical system between the

S1 entrance slit and the S2 intermediate slit is referred to as the first monochromator,
and the optical system between the S2 intermediate slit and the S3 exit slit is referred to
as the second monochromator. Such an optical system, comprised of two

monochromators, is known as a double monochromator. The capability of a double
monochromator reducing stray light makes it indispensable for CD measurement.
The instrument uses crystal prisms (P1 and P2) that have different axial orientations, so

that the light that passes through the monochromator is not only monochromated, but
also linearly polarized, and oscillates in the horizontal direction.
This linearly-polarized light is modulated by the modulator into right and left circularly­polarized beams of light. The modulator subjects quartz to mechanical stress in order
to produce circular polarization in the crystal, based on the principle of the Piezo effect.
When a sample with circular dichroism is placed in the sample chamber, the intensity, I,
of the transmitted light changes as shown in Fig. 1.2 :

Intensity

I

L

I

I

R

A

Time

S

Fig. 1.2 Intensity of transmission light

The relationship between the minimum and maximum intensities and the right and left
circularly-polarized light depends on whether the value E

value E
the dotted line represents the case when E

and S, refer to Section 1.1.1

. In Fig. 1.2, the solid line represents the case when ER is greater than EL, and

L

is smaller than EL. For the definitions of IA

R

″Principles of operation″.

is smaller or larger than the

R

When light with intensity fluctuations such as that shown in Figure 1.2 is incident upon
the photomultiplier tube, the output signal consists of DC components equivalent to I

A

and AC components equivalent to S.

,

1.1.3 Electrical system

The output signal from the detector (PM photomultiplier tube) consists of an AC
component electrically modulated by the modulator and a DC component that
represents the average intensity of the transmission light. The CD value can be derived
from the ratio between the DC component and the AC component. This instrument
varies the PM voltage in order to maintain a constant DC component, and utilizes the
AC component as the CD signal. Therefore, once the AC signal is calibrated using a
standard sample, the correct CD value can be obtained.
Fig 1.3 shows a block diagram of the electrical system. Since the AC and DC
components can be discussed independently, they are described separately in
reference to Figure 1.3.

3

The DC component is separated between the preamplifier and the CD amplifier, and is
compared with the reference voltage in order to control the voltage of the PM power
supply. This voltage is also applied to the PM detector, changing the PM sensitivity.
The AC component is converted to a digital signal after being amplified by the
preamplifier and the CD amplifier.
The main unit and the personal computer communicate through the RS-232C interface.
All parameters of the main unit are designated from the personal computer. The CD
signal and PM voltage are communicated to the personal computer through the RS­232C interface after being converted to digital signal and stored in the buffer memory.

Sensor

Light Source

Light Source
Power Supply

Main Unit

PC

Monochromator

Slit Motor
Driver

Wavelength
Motor Driver

Modulator
Driver

Shutter
Driver

I/O

RS-232C I/F

CPU

RS-232C I/F

Sample
Chamber

Buffer Memory

Program Memory

PM

Preamplifier

CD Amplifier

A/D D/A

PM Power
Supply

External
Input 1

External
Input 2

Keyboard

PC

SVGA

Parallel I/F

CRT Display

Printer

Fig. 1.3 Block diagram of electrical system

1.2 Specifications

Light source : 150W air-cooled xenon lamp, or 450W water-cooled xenon

lamp
Detector : Head-on photomultiplier tube
Modulator : Piezoelastic modulator
Measurement wavelength range : 163 to 900 nm (standard detector)
163 to 1100 nm (optional detector)

Wavelength accuracy : ±0.2 nm at 163 to 180 nm
±0.1 nm at 180 to 250 nm
±0.3 nm at 250 to 500 nm

4

±0.8 nm at 500 to 800 nm
±2.0 nm at 800 to 1100 nm
Wavelength repeatability : ±0.05 nm at 163 to 250 nm
±0.1 nm at 250 to 500 nm
±0.2 nm at 500 to 1100 nm

Spectral bandwidth : 0.01 to 15 nm

Slit width : 1 to 3000 µm

Response : 0.5 msec to 32 sec
Scanning system : Continuous scan
Step scan (Fixed response and auto response system)
Scanning speed : to 10000 nm/min (continuous scan)
Data interval : 0.025 to 10 nm (continuous scan)

0.1 to 100 nm (step scan)

0.5 msec to 60 min (time change)

CD full scale : ±10, 200, 2000 mdeg

CD resolution : 0.0005 mdeg (at

0.01 mdeg (at

0.1 mdeg (at ±2000 mdeg full scale)

Stray light : Not more than 0.0003% (200 nm)
RMS noise : 185 nm : 0.050 mdeg (150W light source)

0.045 mdeg (450W light source)
200 nm : 0.040 mdeg (150W light source)

0.035 mdeg (450W light source)
500 nm : 0.035 mdeg (150W light source)

0.035 mdeg (450 light source)
(spectral bandwidth 1nm, response 16 sec)
Baseline stability : 0.03 mdeg/hr
(spectral bandwidth 1 nm, response 32 sec, wavelength 290

nm)
UV measurement : Single beam measurement
Photometric range : 0 to 5 Abs

Photometric accuracy :
(0 to 1 Abs, checked using NIST SRM 930D filter)
External input terminal : Two channels (input range : -1 to 1 V DC)
Shutter : Opens and closes in front of sample
Sample chamber : Small sample chamber dimensions :

140mm wide × 300mm deep × 130mm high

Large sample chamber dimensions :
305mm wide

Sample stage can be dismounted and remounted and

accepts various accessories.
Equipped with constant temperature water inlet/outlet ports
Nitrogen gas displacement: Atmosphere in the light source unit, monochromator unit,

and sample chamber is displaced using dry nitrogen gas.

Temperature : 20 ±5°C

Humidity : Less than 70%
Dimensions : Main unit (small sample chamber) :

1115mm wide × 570mm deep × 410mm high

±10 mdeg full scale)

±200 mdeg full scale)

±0.01 Abs

× 420mm deep × 270mm high

5

Main unit (large sample chamber) :

1270mm wide × 570mm deep × 410mm high

Weight : Main unit (small sample chamber): 87 kg
Main unit (large sample chamber): 106 kg
Power requirements : 100, 115, 200, 220, 230, 240 V, 50/60 Hz
270 W (150 W light source)
670 W (450 W light source)

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