Canberra 9660 User manual

Model 9660/9660A
ICB Digital Signal
Processor
User’s Manual
9231014G

Copyright 2007, Canberra Industries, Inc. All rights reserved.
The material in this document, including all information, pictures,
graphics and text, is the property of Canberra Industries, Inc. and is
protected by U.S. copyright laws and international copyright
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Canberra expressly grants the purchaser of this product the right to
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including as part of a submission to regulatory or legal authorities
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used for any commercial purpose, or for any use other than that
granted to the purchaser, without the written permission of Canberra
Industries, Inc.
Canberra Industries, 800 Research Parkway, Meriden, CT 06450
Tel: [phone] FAX: [phone] http://www.canberra.com
The information in this document describes the product as accurately
as possible, but is subject to change without notice.
Printed in the United States of America.
Genie is trademark of Canberra Industries, Inc.
For technical assistance, call our Customer Service Hotline at 1-800-
255-6370 or email [email protected].

Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. Controls and Connectors . . . . . . . . . . . . . . . . . . . . . 3
Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Internal Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Genie™ 2000 User Interface and Controls . . . . . . . . . . . . 7
Defining a Detector Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
MID Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Stabilizer Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
DSP Gain Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
DSP Filter Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Acquisition Window Adjust Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Stabilizer Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
DSP Gain Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
DSP Filter Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4. Genie VMS User Interface and Controls . . . . . . . . . . . . . 19
Defining a Detector Input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
ICB DSP 9660 Setup Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
9660 Default Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5. Monitor Output . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Trapezoid Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Using the Monitor Output to Verify System Gain . . . . . . . . . . . . . . . . . . . . . . . . 31
6. Setup and Operation . . . . . . . . . . . . . . . . . . . . . . . 33
Setting the ICB Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Installing the 9660 in a NIM Bin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
i

ICB/MCA Connections – Model 556/556A AIM . . . . . . . . . . . . . . . . . . . . . . . . 34
Initialization and Self-Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Spectroscopy System Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Detector Matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Automatic Pole/Zero Matching (9660A only) . . . . . . . . . . . . . . . . . . . . . . . . . 38
Manual Pole/Zero Matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Automatic Ballistic Deficit Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Spectroscopy Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7. PUR/LTC Operation . . . . . . . . . . . . . . . . . . . . . . . . 47
Pileup Rejection With a Live Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Live Time Correction With a Live Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
PUR Guard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
PUR Guard Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
PUR Guard Adjustment Using a Live Spectrum . . . . . . . . . . . . . . . . . . . . . . . 54
Live Time Correction Using the LFC Module . . . . . . . . . . . . . . . . . . . . . . . . . . 54
LFC System Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
A. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Front Panel Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
ICB Programmable Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Pileup Rejector/Live Time Corrector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Cables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Physical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Environmental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
B. Performance Adjustments . . . . . . . . . . . . . . . . . . . . 63
Rise Time and Flat Top Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
ii Model 9660-9660A ICB Digital Signal Processor

Pole/Zero Matching - Supplementary Information . . . . . . . . . . . . . . . . . . . . . . . . 66
Using a Square Wave Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Pole/Zero Matching and “Wrap Around” . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Baseline Restorer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Manual Fast Discriminator Threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Operation with Reset Preamps and Selecting Inhibit Mode . . . . . . . . . . . . . . . . . . . 72
Configuring the Preamp Reset Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Pole/Zero Setting for Reset Preamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Using the Reset Inhibit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
C. Data and ICB Interface Connectors . . . . . . . . . . . . . . . 76
MCA Data Transfer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Data Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
ICB Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
D. Installation Considerations . . . . . . . . . . . . . . . . . . . . 82
User’s Manual - ICN 9231014G iii

Notes
iv Model 9660-9660A ICB Digital Signal Processor

1. Introduction
The CANBERRA Model 9660 Digital Signal Processor represents the state of the art
in high rate/high resolution pulse processing subsystems for gamma spectroscopy. Us-
ing high speed DSP circuits and sophisticated filtering algorithms, the Model 9660 re-
places the traditional shaping Amplifier/Analog to Digital Converter (ADC)
combination in traditional analog based spectroscopy systems.
The Model 9660 accepts programming information over the 8-bit wide CANBERRA
Instrument Control Bus (ICB). ICB NIMs connect to this bus via a host module such
as the Model 556 Acquisition Interface Module (AIM) as part of a hierarchy of net-
worked acquisition and control managed by a Genie family computing platform.
With traditional analog signal processing, the detector signal is amplified, shaped, fil-
tered and baseline restored by the shaping amplifier. The signal is then digitized by the
ADC at the end of the processing chain. The Model 9660 performs pre-conditioning
and amplification of the signal presented by the preamplifier, then digitizes the signal
directly at a very high sampling rate. The filtering, baseline restoration and optimiza-
tion processes are then applied to the digitized data using real time digital processing
algorithms. This reduces noise effects while making possible the use of more efficient
and sophisticated filtering algorithms than can be achieved in the analog domain. The
net result is a reduced processing time for better throughput with improved resolution
and enhanced stability.
The weighting function applied in the Model 9660 filter algorithm produces a sym-
metrical and near ideal Triangular/Trapezoidal filter function. Trapezoidal shaping re-
quires less processing time for equivalent resolution obtained with semi-Gaussian
shaping. The result is less dead time, less pileup, more events processed and higher
throughput. Conversely, superior resolution results when the trapezoidal processing
time is increased to match a particular semi-Gaussian processing time. The duration of
the trapezoidal flat top can be automatically or manually adjusted to eliminate detector
ballistic deficit and charge collection effects. Triangular shaping is optimal for small
detectors which don’t exhibit ballistic deficit or charge collection irregularities and is
obtained by reducing the trapezoidal flat top to zero.
With the Model 9660, users can achieve count throughput rates in excess of 100 000
counts per second. In general the trade off between resolution and throughput is unsur-
passed when compared to traditional analog electronics. For example, a trial run com-
paring the fastest available analog system, the CANBERRA 2024 Amplifier and 8715
ADC to the 9660 produced a peak resolution of 2.4 FWHM at 70 000 cps for the
9660-compared to 2.6 FWHM for the 2024/8715.
Traditionally, the spectroscopist had to make tradeoffs between resolution and
throughput – the higher the throughput, the poorer the resolution and vice versa. While
this tradeoff still occurs, the 9660 user will observe higher overall throughput or better
resolution at a lower throughput than with analog electronics.
User’s Manual - ICN 9231014G 1

Most adjustments are made through the graphical user interface of the Genie software
environments. Equivalent batch procedure commands are also available in the envi-
ronments. All ICB NIM parameters are stored in the single data file structure of the
Genie family, allowing verification of correct set up from one experiment to the next.
All ICB NIMs feature a characteristic READY LED to indicate operational status.
Software commands initiate automatic measurement of and correction for ballistic def-
icit effects. 9660’s which include an “A” suffix in the model number (9660A) have the
automatic pole/zero option installed. To verify the model please check the serial num-
ber tag located on the NIM power connector. For the Model 9660A the pole/zero ad-
justment can be performed automatically - the process is initiated by the software
command. The pole/zero may also be adjusted manually by the software. For the
Model 9660 without the automatic pole/zero option the pole/zero is adjusted manually
from the software.
The Model 9660 includes a two-point digital stabilizer that provides both gain and
zero stabilization. The stabilizer is programmable and allows adjustment interactively.
Adjustment menus in the software allow the stabilizer to be turned on and off, or
placed in a “hold” state which freezes the adjustments for subsequent counts.
Chapter 1 - Introduction
2 Model 9660-9660A ICB Digital Signal Processor

2. Controls and Connectors
Front Panel
This is a brief description of the 9660 ICB DSP’s front panel LED indicators and con-
nectors. For more detailed information, refer to Appendix A, Specifications.
User’s Manual - ICN 9231014G 3
Front Panel
Figure 1 Front Panel Connectors

Rear Panel
This is a brief description of the 9660 ICB DSP’s rear panel connectors. For more de-
tailed information, refer to Appendix A, Specifications.
Chapter 2 - Controls and Connectors
4 Model 9660-9660A ICB Digital Signal Processor
Figure 2 Rear Panel Connectors

Internal Controls
Front End Board
The two Front End Board jumpers, JP7 and JP8, are not installed on the board; they
are used only during factory calibration.
SW1 is the ICB slave address switch. Select one of sixteen addresses ( 0 through 9, A
through F) for the 9660. The address must be unique in any one system. The factory
default is address.
User’s Manual - ICN 9231014G 5
Internal Controls
Figure 3 Internal Controls, Front End Board
Right Side Cover Removed

Digital Board
Digital Board jumpers are installed at the factory to configure the 9660. If the jumpers
are removed by mistake, please replace them as shown in Figure 4.
W6 - jumper plug installed.
Chapter 2 - Controls and Connectors
6 Model 9660-9660A ICB Digital Signal Processor
Figure 4 Internal Controls, Digital Board
Left Side Cover Removed

3. Genie™ 2000 User Interface and
Controls
The following discussion provides basic information on the user interface and func-
tional operation of the setup controls for the Model 9660 ICB Digital Signal Proces-
sor. Additional details and discussion can be found in Chapter 6, Setup and Operation,
Chapter 7, PUR/LTC Operation, and Appendix B Performance Adjustments.
Unless noted otherwise, all controls are programmable through the host computer soft-
ware. For proper operation, an ICB master (Model 556/556A AIM module) and appro-
priate software (Genie-PC, Genie™ 2000, or Genie-VMS) are required. For specific
details on using the host computer software, please refer to the appropriate software
user’s manual.
Defining a Detector Input
The first step in using a 9660 module is to define a detector input definition at the host
computer that specifies this type of device. The MCA Input Definition (MID) Editor is
used for this purpose under Genie-PC and Genie-2000 (the MID Setup Wizard can
also be used under Genie-2000). To define a detector input using a 9660 module, the
user should select the MCA named “AIM/DSP” from the MCA Selection menu then
click on the Add button (Figure 5).
User’s Manual - ICN 9231014G 7
Defining a Detector Input
Figure 5 MCA Selection Dialog

Once the MCA has been added, then you must configure the Ethernet and memory
size of the AIM module through the Devices/MCA menu (Figure 6). The 9660 module
is thought of as three devices by the Genie-PC / Genie-2000 software: DSP Gain, DSP
Filter, and Stabilizer. The ICB address of the 9660 must be defined via the Devices
menu for any one of the aforementioned devices.
All of the programmable settings are supplied with initial default settings. Note that
some parameters can be only programmed via the MID Editor (configuration only pa-
rameters), some can be only programmed via the Adjust screen (adjust only parame-
ters), some can be programmed in both places. In any event, if the setting is adjusted,
then the new value is remembered as part of the detector input definition and used in
subsequent operations involving the detector input. To simplify setup, the various pa-
rameters have been grouped by function under the device names mentioned earlier.
MID Editor
The following section describes those parameters for the 9660 that can be accessed
from the MID Editor via the Settings menu.
Chapter 3 - Genie™ 2000 User Interface and Controls
8 Model 9660-9660A ICB Digital Signal Processor
Figure 6 Device Menu for AIM with DSP Input

Stabilizer Parameters
The Stabilizer settings screen (Figure 7) for the 9660 contains the following controls.
Gain Centroid
Sets the centroid (in channels) of the reference peak at the high end of the spectrum for
gain stabilization (Figure 8).
User’s Manual - ICN 9231014G 9
MID Editor
Figure 7 MID Editor's Stabilizer Settings Dialog
Figure 8 Relationship Between Stabilizer Functions

Gain Window
Sets the width (in channels) of the upper and lower sampling windows on either side
of the gain reference peak.
Gain Spacing
Sets the spacing (in channels) between the upper and lower sampling windows. The
windows should be placed so that a shift in the reference peak reflects a significant
change in count rate through the window. For broad peaks, the spacing should be set
so that the windows’ edges are not on the flat part of the peak.
Gain Rate Div
The Gain Rate Divisor sets the count rate dividers at the input to the correction register
for Gain. For high count rate reference peaks, increasing the Divider value will smooth
out the correction applied to the system and minimize any peak broadening. This con-
trol can only be set via the MID Editor.
Gain Ratio
The Gain ratio value is interpreted by the stabilizer as the ratio to maintain between
the two gain windows (ratio = upper window / lower window). For instance, a value of
1 would be appropriate for a pure Gaussian peak.
Zero Centroid
Sets the centroid (in channels) of the reference peak at the low end of the spectrum for
zero intercept stabilization.
Zero Window
Sets the width (in channels) of the upper and lower sampling windows on either side
of the zero reference peak.
Zero Spacing
Sets the spacing (in channels) between the upper and lower sampling windows. The
windows should be placed so that a shift in the reference peak reflects a significant
change in count rate through the window. For broad peaks, the spacing should be set
so that the windows edges are not on the flat part of the peak.
Zero Rate Div
The Zero Rate Divisor sets the count rate dividers at the input to the correction register
for Zero intercept. For high count rate reference peaks, increasing the Divider value
will smooth out the correction applied to the system and minimize any peak broaden-
ing. This control can only be set via the MID Editor.
Zero Ratio
The Zero ratio value is interpreted by the stabilizer as the ratio to maintain between the
two zero windows (ratio = upper window / lower window). For instance, a value of 1
would be appropriate for a pure Gaussian peak.
Chapter 3 - Genie™ 2000 User Interface and Controls
10 Model 9660-9660A ICB Digital Signal Processor

Correction Rng
Correction range: 1% (Ge) or 10% (NaI). This control selects the Gain Correction
range that can be provided to correct for drift. Select ±1% for a germanium detector or
±10% for a sodium iodide detector. This control can only be set via the MID Editor.
DSP Gain Parameters
The DSP Gain settings screen (Figure 9) for the 9660 contains the following controls.
Coarse Gain
Sets the device’s coarse gain. It’s best to choose the highest Coarse Gain which, com-
bined with the Fine and Super-Fine Gains, will produce the total desired gain.
Fine Gain
Sets the device’s Fine Gain multiplier.
S-Fine Gain
Sets the device’s Super-Fine Gain value.
The combination of Coarse and Fine Gain sets the overall system gain to match the re-
quirements of the detector and energy application; overall gain is continuously vari-
able from x2.0 to x1536. The Fine Gain factor is dependent on the Super-Fine Gain
(SFG) value. With the SFG set to 0.0000e-2, the Fine Gain covers a range of x0.4 to
x1.6. The SFG value adds to the Fine Gain factor and covers a range of 0.0000e-2 to
3.0000e-2.
User’s Manual - ICN 9231014G 11
MID Editor
Figure 9 MID Editor's DSP Gain Settings Dialog

Coinc Mode
Sets the devices gating mode (ANTIcoincidence or COINCidence). In COINCidence
mode, a positive GATE pulse enables the conversion of the event in process (in ANTI-
coincidence mode, a positive GATE pulse disables the conversion of the event in pro-
cess). To enable/disable an event, the GATE pulse must occur during the trapezoid
rise time and flat top. The Trapezoid signal timing may be viewed on the MONITOR
Output. The GATE pulse duration must be equal to or greater than 50 nanoseconds.
This control can only be set via the MID editor.
Offset
Sets the devices digital offset in channels. The digital offset shifts the memory assign-
ment of the device’s conversions to the left (e.g. an offset value of 4096 would shift
channel 4096 down to correspond to channel zero of the memory).
LLD
Sets the devices Lower Level Discriminator (LLD) as a percentage of the ADC’s full
scale.
Zero
Sets the device’s zero intercept as a percentage of the device’s full scale.
Conv. Gain
Sets the device’s conversion gain. It can be set from 256 to the maximum number of
channels supported by the device. The gain will change by a factor of two. Note that
this value is automatically copied down to the 9660’s internal Conversion Range pa-
rameter.
FDisc Mode
Sets the device’s Fast Discriminator threshold mode. AUTO allows the threshold to be
optimized automatically above the system noise level; MANUAL allows the threshold
to be manually adjusted.
FDisc Setting
Sets the device’s Fast Discriminator threshold level (when MANUAL Fdisc Mode is
selected). The range is 0 to 100%.
Inp. Polarity
Sets the device’s Input signal polarity to either Positive or Negative. The device’s in-
put polarity must match the preamplifier’s output polarity. This control can only be set
via the MID Editor.
Chapter 3 - Genie™ 2000 User Interface and Controls
12 Model 9660-9660A ICB Digital Signal Processor

Inh. Polarity
Sets the device’s Inhibit signal polarity to either Positive or Negative. If you are using
a TRP preamplifier, the Inhibit Polarity control matches the polarity of the device’s In-
hibit (reset) input to the polarity of the preamp’s Inhibit output. This control can only
be set via the MID Editor.
DSP Filter Parameters
The DSP Filter settings screen (Figure 10) for the 9660 contains the following con-
trols.
BLR Mode
Sets the baseline restorer mode. With a setting of AUTO, the baseline restorer is auto-
matically optimized as a function of trapezoid shaping time and count rate. With set-
tings, of SOFT, MEDIUM and HARD, the baseline restorer is set to fixed rates as
selected.
Preamp Type
Selects the Preamplifier type as either TRP (Transistor Reset Preamp type) or RC (RC
coupled preamp type). RC enables the pole/zero adjust screen in the MCA | Ad-
just | Filter Device screen; TRP disables pole/zero adjustment. This control can only
be set via the MID Editor.
Rise Time
Symmetrically sets the rise time and fall time of the digital filter time response. As
with conventional Gaussian shaping, the degree of noise filtering is proportional to the
rise time selection. The rise time can be selected from 35 rise/fall times ranging from
0.4 to 28 µs.
User’s Manual - ICN 9231014G 13
MID Editor
Figure 10 MID Editor's DSP Filter Settings Dialog

Flat Top
Sets the flat top portion of the digital filter time response. The flat top matches the fil-
ter to the detector charge collection characteristics to minimize the effects of ballistic
deficit. The flat top time can be selected from 21 flat top selections ranging from 0 to 3
µs.
Acquisition Window Adjust Screen
The following section describes those parameters for the 9660 that can be accessed
from the Adjust dialog screen. Note that the Adjust screen for a given device may ac-
tually be composed of several screens, which are accessed by using the Next/Prev
pushbuttons.
Stabilizer Parameters
The Stabilizer settings screen (Figure 11) for the 9660 contains the following controls.
Gain Centroid
Sets the centroid (in channels) of the reference peak at the high end of the spectrum for
gain stabilization.
Gain Window
Sets the width (in channels) of the upper and lower sampling windows on either side
of the gain reference peak.
Gain Spacing
Sets the spacing (in channels) between the upper and lower sampling windows. The
windows should be placed so that a shift in the reference peak reflects a significant
change in count rate through the window. For broad peaks, the spacing should be set
so that the windows’ edges are not on the flat part of the peak.
Chapter 3 - Genie™ 2000 User Interface and Controls
14 Model 9660-9660A ICB Digital Signal Processor
Figure 11 Adjust Screen's Stabilizer Settings