Flat panel sensor C7921 is a digital X-ray image sensor newly developed as key devices for non-destructive inspection, biomedical imaging, X-
ray microscopy and other real-time X-ray imaging applications requiring high resolution and high image quality. C7921 consists of a sensor board
and a control board, both assembled in a thin, flat and compact package. The sensor board contains a CsI scintillator plate, a two-dimensional
photodiode array with FET switches and a signal processing IC chip. The photodiode array has a 1056 × 1056 pixel format with minimized
blooming and is highly sensitive to bluish green light emitted from the CsI scintillator. Each row of pixels is addressed in sequence by the vertical
shift register connected to the gate line.
Light emission occurs when X-rays are absorbed in the CsI scintillator. This light emission enters directly into the two-dimensional photodiode
array where an electric charge is stored in each pixel according to the light intensity. This charge is then transferred to the corresponding data line
by applying a control signal to the vertical shift register.
The sensor board also has 8 charge sensitive amplifier arrays each having 132 channel amplifiers with a horizontal shift register. These amplifiers
with a total of 1056 channels are connected to a CDS (Correlated Double Sampling) circuit that senses the charge on each video line and sends it
as the analog video signal from each amplifier array. The control board converts the analog video signal into a 12-bit digital signal and outputs it to
an external frame grabber from a 12-bit parallel port.
C7921 delivers a frame rate of 16 frames per second using 4 × 4 binning and is ideal for high frame rate applications, also ideal for applications
requiring high resolution because of its 50 ľm pixel size. Massive digital image data can easily be monitored on a display unit by using a frame
grabber board and video memory installed in the PC. C7921 will prove ideal tools for real-time X-ray imaging and processing where easy-to-use,
high-resolution X-ray digital image sensors are needed.

Features

l Non-destructive inspection

l Digital X-ray photography

Applications

l High quality image: 1056 × 1056 pixels

l Pixel size: 50 × 50 ľm

l No image distortion

l Digital output (12 bits)

l High-speed imaging by binning operation:

16 frames/s (4 × 4 binning)

l Wide dynamic range

l High cost performance

I M A G E S E N S O R

Flat panel sensor

High resolution and high frame rate

C7921

AMP ARRAY No. 1

SHIFT REGISTER

TIMING
PULSE
GENERATOR

OSCILLATOR

ExtTrg

PIXEL NUMBER

Vsync
Hsync
Pclk

A/D

IntExt

BINNING

(bin0, bin1)

EXTERNAL POWER SUPPLY
A. Vdd, D. Vdd V (ą7.5)
(not attached)

AMP ARRAY No. 8

PHOTODIODE
ARRAY

BUFFER
AMP

PROCESSING
AMP

1115136

1115135

1056

1055

2112

2111

1057

SCINTILLATOR
(52.8 mm × 52.8 mm)

BIAS
GENERATER

FIFO

A/D

FIFO

VIDEO OUTPUT
(12 BIT DIGITAL)

I Block diagram

KACCC0170EA

Flat panel sensor

C7921

I Functional specification

Parameter

Specification

Readout

Charge amplifier array

Feedback capacitance of each amplifier

0.15 pF

Video output (Data1 - 12)

RS-422 (differential) 12 bit

Output data rate

6.25 MHz

Synchronous signal (Vsync, Hsync, Pclk)

RS-422 (differential)

bin0, 1, ExtTrg, IntExt

TTL

I Absolute maximum ratings (Ta=25 °C)

Parameter

Symbol

Value

Unit

Supply voltage for digital circuitry (+5 V)

D.vdd

+6.0

Supply voltage for analog circuitry (+5 V)

A.vdd

+6.0

Supply voltage for analog circuitry (ą7.5 V)

V(+/-7.5)

ą12

Operating temperature (not condensed)

Topr

0 to +35

°C

Storage temperature (not condensed)

Tstg

0 to +50

°C

I Specification (Unless otherwise noted, Typ. Ta=25 °C A.vdd= 5.0 V, D.vdd= 5.0 V, V (ą7.5)= ą7.5 V)

Parameter

Symbol

Specification

Unit

Pixel size

ľm

Active area

52.8 × 52.8

Pixel number

1056 × 1056

pixels

Number of active pixels

1032 × 1032

pixels

Frame speed (single operation)

Sf (int)

frame/s

Frame speed (2 × 2 binning)

frame/s

Frame speed (4 × 4 binning)

frame/s

Frame speed external (single operation )

Sf (ext)

Sf (int) to 0.1

frame/s

Noise (rms.)

N (rms.)

1000

electrons

Saturation charge

Csat

2.9

M electrons

Resolution

Reso

line pairs/mm

Dynamic range

2900

Defect line *

10 Max.

lines

Scintillator

CsI

* Without a couple of adjacent defect line that has no response.

I Timing chart

To acquire images through an image grabber board, parameters that match the following timing chart should be described in the
software program or parameter file.

Internal mode

KACCC0167EA

Vsync+
(RS-422)

Hsync+
(RS-422)

Pclk+
(RS-422)

Data1 - 12
(RS-422)

The number of n is 132

Tvc (1 FRAME)

Thd

Thdpw

Thc (1 LINE)

Tvdpw

Thdpw

Thc (1 LINE)

Tpd

Tpdb

Tpc (1 PIXEL)

Tppw

Tpdb

n-1

n+1

8n-1

Tdc

Tdd

Flat panel sensor

C7921

External mode

KACCC0139EB

1 × 1 mode (Typ.)

Parameter

Symbol

Value

Unit

Delay time (only external trigger mode)

Tvd

450

ľs

Cycle time

Tvc

243

Vsync

Dummy pulse width

Tvdpw

920

ľs

Delay time

Thd

2.8

ľs

Cycle time

Thc

230

ľs

Hsync

Dummy pulse width

Thdpw

ľs

Delay time

Tpd

150

Cycle time

Tpc

160

Pulse width

Tppw

Pclk

Delay time between each block

Tpdb

480

Delay time

Tdd

Data1-12

Cycle time

Tdc

160

2 × 2 mode (Typ.)

Parameter

Symbol

Value

Unit

Delay time (only external trigger mode)

Tvd

450

ľs

Cycle time

Tvc

122

Vsync

Dummy pulse width

Tvdpw

920

ľs

Delay time

Thd

2.8

ľs

Cycle time

Thc

230

ľs

Hsync

Dummy pulse width

Thdpw

140

ľs

Delay time

Tpd

150

Cycle time

Tpc

160

Pulse width

Tppw

Pclk

Delay time between each block

Tpdb

480

Delay time

Tdd

Data1-12

Cycle time

Tdc

160

4 × 4 mode (Typ.)

Parameter

Symbol

Value

Unit

Delay time (only external trigger mode)

Tvd

450

ľs

Cycle time

Tvc

Vsync

Dummy pulse width

Tvdpw

920

ľs

Delay time

Thd

2.8

ľs

Cycle time

Thc

230

ľs

Hsync

Dummy pulse width

Thdpw

190

ľs

Delay time

Tpd

150

Cycle time

Tpc

160

Pulse width

Tppw

Pclk

Delay time between each block

Tpdb

480

Delay time

Tdd

Data1-12

Cycle time

Tdc

160

Note) The numbers of siginificant figures is two. (except Tvc)

RECOMMENDATION: 50 % OF FRAME TIME

FROM Tvc TO 10 s

Tvc - Tvdpw

Tvd

ExtTrg
(TTL)

Vsync+
(RS-422)

Hsync+, Pclk and Data 1-12 are the same as internal trigger mode.

Flat panel sensor

C7921

I System requirements

To operate C7921 at full performance, the following system and peripherals are required.
PC: IBM compatible PC running on Windows 98 or later operating system
Digital frame grabber card: Monochrome 16 bits or more, pixel clock 7 MHz or more, RS-422 interface synchronous signal (See
the frame grabber manual.)
The National Instruments IMAQ PCI-1424 (NI parts No. 777662-01) frame grabber has been verified to successfully acquire 12-
bit digital images from C7921. The IMAQ PCI-1422 (NI pats No. 777959-01) also acquires satisfactory images from C7921. You
can utilize the demonstration software that comes with the frame grabber as a simple viewer, to acquire and save an image. To do
so, refer to the frame grabber user's guide for how to use the camera information file for the demonstration software.

Power source: A. Vdd = +5.0 ą 0.1 V (700 mA), D. Vdd = +5.0 ą 0.1 V (800 mA), V (ą7.5) = ą7.5 ą 0.5 V (ą100 mA). Use of a series
power supply is recommended. (Avoid using a switching power supply.) A power cable (terminated with an FGG.2B.307.CLAD92Z
plug at one end and open at the other end; 2 m; see Table 2.) comes supplied with C7921. An optional 36-pin cable for interface
with the 36-pin receptacle (see Table 1) on C7921 is also available for synchronous signal input, video output and external
control.
The voltages described above are specified at the flat panel sensor side. The impedance of the power cable attached with the
flat panel sensor is low enough but it causes 0.1 V approx. drop. Therefore the voltage at the power source side should be set
0.1 V higher than the voltage specified above.

Table 1 Pin assignment of 36-pin receptacle

Pin No.

Signal

Pin No.

Signal

Data1+ (MSB)

Data1- (MSB)

Data2+

Data2-

Data3+

Data3-

Data4+

Data4-

Data5+

Data5-

Data6+

Data6-

Data7+

Data7-

Data8+

Data8-

Data9+

Data9-

Data10+

Data10-

Data11+

Data11-

Data12+(LSB)

Data12- (LSB)

bin0 (TTL)

Gnd

bin1 (TTL)

Gnd

ExtTrg (TTL)

IntExt (TTL)

Vsync+

Vsync-

Hsync+

Hsync-

Pclk+

Pclk-

Unless otherwise noted, signal level is RS-422.

36-pin receptacle: TX20A-36R-D2GF1-A1L made by JAE (Japan Aviation Electronics Industry limited)

36-pin mating plug: TX20A-36PH1-D2P1-D1 made by JAE (Japan Aviation Electronics Industry limited)

Table 2 Power pin assignment and cable color

Pin No.

Color

Signal

Brown

+7.5 V

Red

Analog GND

Orange

-7.5 V

Yellow

Analog GND

Green

Analog +5 V

Blue

Digital GND

Purple

Digital +5 V

Shield

Analog GND

7-pin power plug: FGG.2B.307.CLAD92Z made by LEMO S. A. (http://www.lemo.ch)

7-pin power receptacle: ECG.2B.307.CLV made by LEMO S. A.

Flat panel sensor

C7921

I Connection

Install the frame grabber board into the PC by following the manufacturer's instructions. When a general-purpose frame
grabber board is used, binning or trigger operation for bin0, bin1, IntExt and ExtTrig can be controlled with its digital I/O control.

KACCC0168EA

VIDEO OUTPUT
(12 BIT DIGITAL)
Vsync, Hsync,
Pclk

BINNING
(bin0, bin1)
IntExt
ExtTrg

X-RAY SOURCE

GRABBER

MONITOR

PC/AT

(REAR VIEW)

C7921

OS +
ACQUISITION
SOFTWARE

VOLTAGE
SOURCE
[A. Vdd, D. Vdd, V (ą7.5)]

MOS Image Sensor for X-Ray

I Dimensional outline (unit: mm)

KACCA0103EA

142

MOS Image Sensor for X-Ray

C7921

Top cover is made of aluminum 1.0 mm thickness.
Weight: 1.37 kg

52.8

Digital Out

Power

Part Number C7921