12th Int. Beam Instrum. Conf.
ISBN: 9 7 8 - 3 - 9 5 4 5 0 - 2 3 6 - 3

IBIC2023, Saskatoon, Canada
JACoW Publishing
ISSN: 2 6 7 3 - 5 3 5 0d o i : 1 0 . 1 8 4 2 9 / J A C o W - I B I C 2 0 2 3 - W E P 0 2 9L. Montoya†, S. Johnson, H. Watkins, D. Zimmermann
Los Alamos National Laboratory, Los Alamos, NM, USA
Abstract
High density instrumentation has been developed to upgrade wire scanner beam diagnostic capability in all areas
downstream of the Coupled Cavity (CCL) LINAC (LinearAccelerator). Transverse beam profile measurements wereoriginally obtained using legacy electronics known as
Computer Automated Measurement and Control(CAMAC) crates. CAMAC has become obsolete, and a
new wire scanner diagnostic system was developed as a replacement. With high wire scanner device density locatedin each area, instrumentation was developed to meet thatneed along with the ability to interface with legacy openloop controlled actuators and be forward compatible with
upgraded closed-loop systems. A high-density system wasdeveloped using a Quad Actuator Controller (QAC) andData Acquisition (DAQ) chassis that pair together using asequencer when taking measurements. Software improvements were also made, allowing for full waveform functionality that was previously unavailable. Deployment of52 wire scanner locations in 2022 increased device availability and functionality across the facility. Hardware andsoftware design details along with results from accelerator
beam measurements are presented.

INTRODUCTION
Legacy diagnostic instrumentation used at the Los Alamos Neutron Science Center (LANSCE) have become obsolete with no readily available spares for CAMAC systems. Because of the density of devices downstream of theCCL a high-density solution was needed.
A new wire scanner instrumentation system has been developed and implemented by the LANSCE controls hardware team to replace CAMAC and interface with legacy
devices. Software was developed to interface the old devices with the new hardware, primarily the embedded andclient software.

SYSTEM OVERVIEW
Wire scanners are electro-mechanical beam interceptive
devices that provide cross-sectional beam profile measurements that describe beam shape and position. A wire scanner system consists of an actuator to drive the sense wires
across the beam, and data acquisition to obtain the waveform data from the current induced by the proton beam impinging on the wire. The wire scanner hardware architecture diagram is shown in Fig. 1.
___________________________________________* This work was supported by the U.S. Department of Energy throughthe Los Alamos National Laboratory. Los Alamos National Laboratoryis operated by Triad National Security, LLC, for the National Nuclear
Security Administration of U.S. Department of Energy (Contract No.
89233218CNA000001).
† lucasm@lanl.gov. LA-UR-23-30151

Figure 1: Wire scanner hardware diagram.

CONTROLLER HARDWARE
The electronic hardware consists primarily of two separate chassis, each controlled using a National Instruments(NI) 9038 compact Reconfigurable Input/Output (cRIO)
packaged in 4U rack mountable enclosures configured as
input output controllers (IOC). The QAC chassis controls
the wire scanner actuators, and the DAQ chassis is used fordata acquisition from the beam induced current on the wire.

Quad Actuator Controller
The QAC chassis was designed to control up to fourstepper motor actuators, two actuators simultaneous. The
chassis is compatible with both open loop and closed loop
motion control to be forward compatible with potential actuator upgrades to resolver position closed loop control as
was done on the LANSCE risk mitigation project [1].
Within the cRIO controller on the QAC is housed NI I/O
modules, and serve as the interface between the wire scanner actuator and the cRIO and perform the functions as follows:NI 9401 digital I/O for stepper motor and brakecontrol

 NI 9421 sinking digital input for limit switch indication
 NI 9222 voltage input potentiometer position feedback, for open loop control
 RDK 9316 resolver to digital converter, for closed
loop only
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Content from this work may be used under the terms of the CC-BY-4.0 licence (© 2023). Any distribution of this work must maintain attribution to the author(s), title of the work, publisher, and DOILANSCE QAC/DAQ WIRE SCANNER INSTRUMENTATION UPGRADE*

Content from this work may be used under the terms of the CC-BY-4.0 licence (© 2023). Any distribution of this work must maintain attribution to the author(s), title of the work, publisher, and DOI

12th Int. Beam Instrum. Conf.
ISBN: 9 7 8 - 3 - 9 5 4 5 0 - 2 3 6 - 3IBIC2023, Saskatoon, Canada
JACoW Publishing
ISSN: 2 6 7 3 - 5 3 5 0d o i : 1 0 . 1 8 4 2 9 / J A C o W - I B I C 2 0 2 3 - W E P 0 2 9In addition to the cRIO, the QAC chassis consists of four
stepper motor drivers, four solid state relays for electricallyreleased brake, two signal distribution boards, a touch display, 10V potentiometer power supply and 24V power supplies for the cRIO and actuator power. The QAC chassis isshown in Fig. 2.

Figure 3: Vertical and Horizontal Axis Beam Profiles.

Figure 2: QAC chassis.

Data Acquisition
The DAQ chassis is capable of 32 channel, 100 kS/channel, simultaneous waveform acquisition (10µs resolution)with a compact Peripheral Component Interconnect backplane with two high density 16 channel each, gain adjustable, 2 kΩ input impedance Analog Front End (AFE) conditioning card capable of reading from 270 µA down to3 µA current levels [2]. The NI I/O modules installed into
the cRIO consist of an NI 9403 for AFE gain setting, twoNI 9220 digitizers, and an NI 9401 digital I/O for beamgate input. The DAQ chassis is expandable from 32 channels to 80 by adding AFE cards and 9220 digitizer modules
depending on the area device density.

Figure 4: Vertical and horizontal axis waveform.

Sequencer

Challenges

A sequencer was implemented as a soft IOC to coordinate motion and data acquisition between the QAC andDAQ hardware during a scan. The sequencer also sets allscan parameters for the measurement. When in scan modethe sequencer initiates the scan, awaits a beam gate trigger,
and acquires the waveform for that beam pulse, commands
the next actuator position and repeats until a scan is completed.

The challenge encountered during development was insufficient gain on the 2K AFE in obtaining data from Micro
Pulse Enable Gate (MPEG) beam. To mitigate the lack ofgain, legacy transimpedance amplifiers were used in a dual
stage amplification in conjunction with the 2K AFE which
was sufficient in providing the amplification needed to obtain beam profile waveforms.
A transimpedance AFE was implemented to accommodate the wider gain range and allow for dependence on legacy amplifiers to no longer be needed. [3]BEAM MEASUREMENT RESULTS
Beam profile measurements were taken using Long
Bunch Enable Gate beam, set to 4 Hz rep rate with 150 µs
beam length. As shown in Fig. 3, a Gaussian profile wasobtained.
The full waveform can be seen in Fig. 4 for the samescan taken in Fig. 3. Each trace is a waveform from a separate beam pulse as the wire scanned across the beam.

CONCLUSIONAll 52 wire scanner locations have been successfully upgraded with each device tested and validated with beam,providing beam profile measurements for each location
this past run cycle during the 2022 calendar year.

WEP029416

03 Transverse Profile and Emittance Monitors

IBIC2023, Saskatoon, Canada
JACoW Publishing
ISSN: 2 6 7 3 - 5 3 5 0
d o i : 1 0 . 1 8 4 2 9 / J A C o W - I B I C 2 0 2 3 - W E P 0 2 9

REFERENCES[1] J. D. Sedillo, J. D. Gilpatrick, F. Gonzales, V. Kutac, D. Martinez, and M. E. Gruchalla, “First Test Results of the New
LANSCE Wire Scanner”, in Proc. PAC'11, New York, NY,USA, Mar.-Apr. 2011, paper MOP236, pp. 554-556.
[2] J. D. Sedillo et al, “LANSCE Isotope Production Facility
Emittance Measurement System”, in Proc. IBIC'16, Barcelona, Spain, Sep. 2016, pp. 548-550.
doi:10.18429/JACoW-IBIC2016-TUPG79[3] D. Rai, et al., “Implementation of Transimpedance Analog
Front End Card for Los Alamos Neutron Science Center Accelerator Wire Scanners,” presented at IBIC2023, Saskatoon,Canada, September 2023, paper WEP042, this conference.

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12th Int. Beam Instrum. Conf.
ISBN: 9 7 8 - 3 - 9 5 4 5 0 - 2 3 6 - 3