XIA Pixie-16 MZ-TrigIO User manual

User's Manual
Digital Gamma Finder (DGF)
PIXIE-16
Version 1.40, October 2009
XIA LLC
31057 Genstar Rd.
Hayward, CA 94544 USA
Phone: [phone]; Fax: [phone]
http://www.xia.com

Disclaimer
Information furnished by XIA is believed to be accurate and reliable. However, XIA assumes no
responsibility for its use, or for any infringement of patents, or other rights of third parties, which
may result from its use. No license is granted by implication or otherwise under the patent rights
of XIA. XIA reserves the right to change the DGF product, its documentation, and the supporting
software without prior notice.

PIXIE-16 User’s Manual V1.40
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Table of Contents
DISCLAIMER ............................................................................................................................................................. I
TABLE OF CONTENTS ...........................................................................................................................................II
SAFETY .................................................................................................................................................................... IV
SPECIFIC PRECAUTIONS ........................................................................................................................................... IV
END USERS AGREEMENT.....................................................................................................................................V
CONTACT INFORMATION .......................................................................................................................................... V
1 OVERVIEW .......................................................................................................................................................1
1.1 APPLICATIONS.............................................................................................................................................1
1.2 FEATURES ...................................................................................................................................................1
1.3 SPECIFICATIONS ..........................................................................................................................................2
2 SETTING UP......................................................................................................................................................4
2.1 INSTALLATION.............................................................................................................................................4
2.2 GETTING STARTED ......................................................................................................................................4
2.2.1 Startup ...................................................................................................................................................4
2.2.2 Settings...................................................................................................................................................5
2.2.3 Run.........................................................................................................................................................5
2.2.4 Results....................................................................................................................................................5
3 NAVIGATING THE PIXIE-16 USER INTERFACE.....................................................................................6
3.1 OVERVIEW ..................................................................................................................................................6
3.2 STARTUP .....................................................................................................................................................7
3.3 SETTINGS ....................................................................................................................................................8
3.3.1 Filter ......................................................................................................................................................8
3.3.2 Analog Signal Conditioning & Acquire ADC Traces ............................................................................9
3.3.3 Histogram Control...............................................................................................................................10
3.3.4 Decay Time ..........................................................................................................................................11
3.3.5 Pulse Shape Analysis ...........................................................................................................................11
3.3.6 Baseline Control & Acquire Baselines ................................................................................................11
3.3.7 Control Registers .................................................................................................................................11
3.3.8 CFD Trigger ........................................................................................................................................12
3.3.9 Trigger Stretch Lengths .......................................................................................................................13
3.3.10 FIFO Delays ...................................................................................................................................13
3.3.11 Multiplicity......................................................................................................................................13
3.3.12 QDC ................................................................................................................................................15
3.4 RUN...........................................................................................................................................................15
3.5 RESULTS....................................................................................................................................................16
4 DATA RUNS AND DATA STRUCTURES...................................................................................................19
4.1 RUN TYPES ................................................................................................................................................19
4.1.1 Histogram Runs ...................................................................................................................................19
4.1.2 List Mode Runs ....................................................................................................................................19
4.2 OUTPUT DATA STRUCTURES ......................................................................................................................19
4.2.1 MCA histogram data............................................................................................................................19
4.2.2 List mode data......................................................................................................................................19
5 HARDWARE DESCRIPTION.......................................................................................................................23

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5.1 ANALOG SIGNAL CONDITIONING ...............................................................................................................23
5.2 TRIGGER/FILTER FPGAS...........................................................................................................................23
5.3 DIGITAL SIGNAL PROCESSOR (DSP) ..........................................................................................................24
5.4 PCI AND TRIGGER INTERFACE...................................................................................................................25
6 THEORY OF OPERATION...........................................................................................................................26
6.1 DIGITAL FILTERS FOR γ-RAY DETECTORS ..................................................................................................26
6.2 TRAPEZOIDAL FILTERING IN THE PIXIE-16 ................................................................................................28
6.3 BASELINES AND PREAMPLIFIER DECAY TIMES ...........................................................................................29
6.4 THRESHOLDS AND PILE-UP INSPECTION ....................................................................................................30
6.5 FILTER RANGE ...........................................................................................................................................33
7 OPERATING MULTIPLE PIXIE-16 MODULES SYNCHRONOUSLY..................................................34
7.1 CLOCK DISTRIBUTION................................................................................................................................34
7.1.1 Individual Clock mode.........................................................................................................................34
7.1.2 Daisy-chained Clock Mode..................................................................................................................35
7.1.3 PXI Clock Mode...................................................................................................................................35
7.1.4 Multi-Chassis Clock Mode...................................................................................................................35
7.2 FRONT PANEL LVDS I/O PORT ..................................................................................................................35
7.3 FRONT PANEL DIGITAL I/O PORT PIN .........................................................................................................36
7.4 SAMPLE SIGNALS FOR FRONT PANEL TEST PINS .........................................................................................37
7.5 TRIGGER DISTRIBUTION.............................................................................................................................39
7.5.1 Trigger Distribution within a Module..................................................................................................39
7.5.2 Trigger Distribution between Modules................................................................................................39
7.5.3 Trigger Distribution between Chassis .................................................................................................39
7.6 RUN SYNCHRONIZATION ...........................................................................................................................39
8 TROUBLESHOOTING ..................................................................................................................................40
8.1 STARTUP PROBLEMS .................................................................................................................................40
9 APPENDIX A ...................................................................................................................................................41
9.1 JUMPERS....................................................................................................................................................41
9.2 PXI BACKPLANE PIN FUNCTIONS ...............................................................................................................41
9.3 PINOUT OF DIGITAL FRONT PANEL CONNECTORS .....................................................................................42

PIXIE-16 User’s Manual V1.40
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Safety
Please take a moment to review these safety precautions. They are provided both for your
protection and to prevent damage to the digital gamma finder (DGF) and connected equipment.
This safety information applies to all operators and service personnel.
Specific Precautions
Observe all of these precautions to ensure your personal safety and to prevent damage to either
the DGF-Pixie-16 or equipment connected to it.
Do Not Hot-Swap!
To avoid personal injury, and/or damage to the DGF-Pixie-16, always turn off crate
power before removing the DGF-Pixie-16 from the crate!
Servicing and Cleaning
To avoid personal injury, and/or damage to the DGF-Pixie-16, do not attempt to repair or
clean the unit. The DGF hardware is warranted against all defects for 1 year. Please contact the
factory or your distributor before returning items for service.

PIXIE-16 User’s Manual V1.40
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End Users Agreement
XIA LLC warrants that this product will be free from defects in materials and workmanship
for a period of one (1) year from the date of shipment. If any such product proves defective
during this warranty period, XIA LLC, at its option, will either repair the defective products
without charge for parts and labor, or will provide a replacement in exchange for the defective
product.
In order to obtain service under this warranty, Customer must notify XIA LLC of the defect
before the expiration of the warranty period and make suitable arrangements for the performance
of the service.
This warranty shall not apply to any defect, failure or damage caused by improper uses or
inadequate care. XIA LLC shall not be obligated to furnish service under this warranty a) to
repair damage resulting from attempts by personnel other than XIA LLC representatives to repair
or service the product; or b) to repair damage resulting from improper use or connection to
incompatible equipment.
THIS WARRANTY IS GIVEN BY XIA LLC WITH RESPECT TO THIS PRODUCT IN
LIEU OF ANY OTHER WARRANTIES, EXPRESSED OR IMPLIED. XIA LLC AND ITS
VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE. XIA’S RESPONSIBILITY TO REPAIR OR
REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY
PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY. XIA LLC AND
ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL,
OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER XIA LLC OR THE
VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.
Contact Information
XIA LLC
31057 Genstar Rd.
Hayward, CA 94544 USA
Telephone: [phone]
Downloads: http://www.xia.com/DGF_Pixie-16_Download.html
Hardware Support: [e-mail]
Software Support: [e-mail]

PIXIE-16 User’s Manual V1.40
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1 Overview
The Digital Gamma Finder (DGF) family of digital pulse processors features unique
capabilities for measuring both the amplitude and shape of pulses in nuclear spectroscopy
applications. The DGF architecture was originally developed for use with arrays of multi-
segmented HPGe gamma ray detectors, but has since been applied to an ever broadening range
of applications.
The DGF Pixie-16 is a 16-channel all-digital waveform acquisition and spectrometer card
based on the CompactPCI/PXI standard for fast data readout to the host. It combines
spectroscopy with waveform digitizing and the option of on-line pulse shape analysis. The Pixie-
16 accepts signals from virtually any radiation detector. Incoming signals are digitized by 12-bit
100 MSPS ADCs. Waveforms of up to 80 µs in length for each channel can be stored in a FIFO.
The waveforms are available for onboard pulse shape analysis, which can be customized by
adding user functions to the core processing software. Waveforms, timestamps, and the results of
the pulse shape analysis can be read out by the host system for further off-line processing. Pulse
heights are calculated to 16-bit precision and can be binned into spectra with up to 32K channels.
The Pixie-16 supports coincidence spectroscopy and can recognize complex hit patterns.
Data readout rates through the CompactPCI/PXI backplane to the host computer can be up to
109 Mbyte/s. The standard PXI backplane, as well as additional custom backplane connections
are used to distribute clocks and trigger signals between several Pixie-16 modules for group
operation. A complete data acquisition and processing systems can be built by combining Pixie-
16 modules with commercially available CompactPCI/PXI processor, controller or I/O modules
in the same chassis.
1.1 Applications
The Pixie-16 is an instrument for waveform acquisition and MCA histogramming for arrays of
gamma ray or other radiation detectors such as
•Segmented HPGe detectors.
•Scintillator/PMT combinations: NaI, CsI, BGO and many others.
•Cryogenic microcalorimeters.
•Silicon strip detectors.
1.2 Features
•Directly accepts signals from RC-type preamplifiers, photomultiplier tubes or other pulse
sources.
•Two software selectable gain/attenuation settings for each analog input.
•Programmable DC-offset for each analog input.
•Digitization of 16 analog inputs in parallel at a rate of 100 MHz.
•Digital filtering with programmable filter peaking times from 0.04 to 81.28 µs (0.04 µs to
5.24 ms with alternate firmware).
•Built-in pileup inspection and pileup rejection.
•Synchronous waveform acquisition (up to 8k samples per channel) across channels and
modules.

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•Event processing and optional pulse shape analysis performed with 100 MHz, 32-bit
floating point SHARC DSP.
•Accumulation of 16 MCA histograms (32K bins) and acquisition of event by event list
mode data.
•More than 160 backplane lines for clock and trigger distribution or general purpose I/O
between modules.
•Supports 32-bit, 33 MHz PCI data transfers (>100 Mbyte/second) to host computer.
•Graphical user interfaces to control and diagnose system.
•Digital oscilloscope for health-of-system analysis.
•Compact C driver libraries available for easy integration in existing user interface.
1.3 Specifications
Front Panel I/O
Analog Signal
Input
16 analog inputs.
Input impedance: 1kΩor 50 Ohm.
Input amplitude ±1V pulsed, ±1.5V DC.
Digitized at 100MSPS, 12-bit precision.
Digital General
Purpose I/O
16 general purpose input and /or output connections:
6 inputs 3.3V LVTTL logic.
6 outputs 3.3V LVTTL logic.
4 inputs/outputs LVDS signaling.
Rev-D modules have 16 LVDS pairs of Channel VETO input and 1 LVDS
pair of Module VETO input
Backplane I/O
Clock Distributed 50 MHz clock, daisy-chained or dedicated line from slot 2.
Triggers Two trigger busses on PXI backplane for synchronous waveform acquisition
and for event triggers.
Synchronization SYNC signal distributed through PXI backplane to synchronize timers and
run start/stop to 50 ns.
Veto VETO signal distributed through PXI backplane to suppress event triggering.
General Purpose
I/O
160 bussed and neighboring lines on custom backplane to distribute hit
patterns and triggers and for I/O between modules.
Host Interface
PCI 32-bit, 33MHz Read/Write, external memory or FIFO readout rate to host
over 100 MByte/s.
Digital Controls
Gain Two software selectable analog gains: 4 and 0.9 (by 1:0.22 attenuation).
Optional +/- 10% digital gain for gain matching between channels.
Offset DC offset adjustment from –1.5V to +1.5V, in 65536 steps.

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Shaping Digital trapezoidal filter.
Rise time and flat top set independently: 0.04 to 81.28 µs (0.04 µs to 5.24
ms with alternate firmware).
Trigger Digital trapezoidal trigger filter with adjustable threshold.
Rise time and flat top set independently: 0.01 to 0.64 µs (0.01 to 40.96 µs
with alternate firmware).
Data Outputs
Spectrum 32k bins, 32 bit deep (4.2 billion counts/bin) for each channel.
256K×18bit FIFO memory for list mode data
Statistics Real time, live time, input and output counts.
Event data Hit pattern, pulse height (energy), timestamps, pulse shape analysis results,
and waveform data.

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2 Setting up
2.1 Installation
The Pixie-16 modules must be operated in a custom 6U CompactPCI/PXI chassis providing
high currents at specific voltages not included in the CompactPCI/PXI standard
1
. Currently XIA
provides an 8-slot and a 14-slot chassis; please inquire for further options. Put the host computer
(or remote PXI controller) in the system slot (slot 1) of your chassis. Put the Pixie-16 modules
into any free peripheral slot (slot 2-8 or 2-14) with the chassis still powered down. After modules
are installed, power up the chassis (Pixie-16 modules are not hot swappable). If using a remote
controller, be sure to boot the host computer after powering up the chassis.
Connect the output of your detector to the small coaxial connectors on the Pixie-16 front
panels. For Rev-A modules, these connectors are of type MMCX. For Rev-B, C, and D modules,
the connectors are of type SMB. The 2 mm front panel headers (and, on the Rev-B, C, and D
modules, the CAT-5 connector) are for logic I/O. Preamplifier power can be connected to the
DB-9 connectors on the front panel of the 6U chassis.
The Pixie-16 software includes the firmware files and DSP code files required to configure a
module, Windows drivers and a Visual Basic graphical user interface. All files are included on
the distribution CD-ROM and can be installed by running the installation program Setup.exe.
Follow the instructions shown on the screen to install the software to the default folder selected
by the installation program, or to a custom folder. This folder will contain 7 subfolders named
Doc, Drivers, DSP, Firmware, MCA, PulseShape, and Resources. Make sure you keep this
folder organization intact, as the interface program and future updates rely on this. Feel free,
however, to add folders and subfolders for the output data at your convenience.
2.2 Getting Started
This section describes the basic steps to get initial list mode traces or MCA histograms with
the Pixie-16 system. For a detailed introduction to the software interface, refer to section 3.
After installation, find the shortcut Pixie16_VB on your desktop and start it with a double
click. You can also directly run the file Pixie16_VB.exe in the installation folder.
The user interface consists of a left control bar with 4 tabs: Startup, Settings, Run, and Results.
The area to the right will display control panels or graphs. The top menu bar contains links to
some frequently used result displays as well as some advanced parameter tables.
2.2.1 Startup
To boot the modules, select the default Startup tab. Enter the number of modules and specify
the module’s slot numbers. You can click the Select Configuration Files button to verify the boot
files and paths are pointed to the installation folder. Then click the button Boot Pixie-16
Modules. You might hear several clicks from the modules as the gain relays are reset, then the
1
Of the 5 backplane connectors available in a 6U format, the lower two are defined by the CompactPCI/PXI
standard, providing basic supply voltages, PCI host I/O, and basic trigger connections. Pixie-16 modules follow this
standard and are thus compatible with any CompactPCI/PXI module that uses these two connectors only. The upper
three connectors are undefined in the CompactPCI/PXI standard. On Pixie-16 modules, these connectors are used
for custom power supplies with high currents (1.8V, 5.5V, 3.3V) and for extended trigger distribution. Third party
modules or chassis using the upper three connectors are most likely not compatible with Pixie-16 modules.