BNL, Upton, New York, USA
ORNL, Oak Ridge, Tennessee, USA
ORNL RAD, Oak Ridge, Tennessee, USA
TimePix3 is a 65k hybrid pixel readout chip with simultaneous Time-of-Arrival (ToA) and Time-over-Threshold (ToT) recording in each pixel*. The chip operates without a trigger signal with a sparse readout where only pixels containing events are read out. The flexible architecture allows 40 MHits/s/cm2 readout throughput, using simultaneous readout and acquisition by sharing readout logic with transport logic of superpixel matrix formed using 2x4 structure. The chip ToA records 1.5625 ns time resolution. The X-ray and charged particle events are counted directly. However, indirect neutron counts use 6Li fission in a scintillator matrix, such as ZnS(Ag). The fission space-charge region is limited to 5-9 um. A photon from scintillator material excites a photocathode electron, which is further multiplied in dual-stack MCP. The neutron count event is a cluster of electron events at the chip. We report on the EPICS areaDetector** ADTimePix3 driver that controls Serval*** using json commands. The driver directs data to storage and to a real-time processing pipeline and configures the chip. The time-stamped data are stored in raw .tpx3 file format and passed through a socket where the clustering software identifies individual neutron events. The conventional 2D images are available as images for each exposure frame, and a preview is useful for sample alignment. The areaDetector driver allows integration of time-enhanced capabilities of this detector into SNS beamlines controls and unprecedented time resolution.
*T Poikela et al 2014 JINST 9 C05013.
**https://github.com/areaDetector
***Software provided by the vendor (ASI) that interfaces detector (10GE) and EPICS data acquisition ioc ADTimePix3
BNL, Upton, New York, USA
ORNL, Oak Ridge, Tennessee, USA
ORNL RAD, Oak Ridge, Tennessee, USA
Detector events at User Facilities require real-time fast transport of large data sets. Since construction, the SNS user facility successfully transported data using an in-house solution based on Channel Link LVDS point-to-point data protocol. Data transport solutions developed more recently have higher speed and more robustness; however, the significant hardware infrastructure investment limits migration to them. Compared to newer solutions the existing SNS LVDS data transport uses only parity error detection and LVDS frame error detection. The used channel link is DC coupled, and thus sensitive to noise from the electrical environment since it is difficult to maintain the same LVDS common reference potential over an extensive system of electronic boards in detector array networks. The SNS existing Channel Link* uses LVDS for data transport with clock of about 40 MHz and a mixture of parallel and serial data transport. The 7 bits per twisted pair in each clock cycle are transported over three pairs of Cat7 cable. The maximum data rate is about 840 Mbps per cat7 cable. The DS90CR217 or DS90CR218 and SN65LVDS32BD components are used with shielded Cat7 cabling in transporting LVDS data. Here we discuss noise mitigation methods to improve data transport within the existing as build infrastructure. We consider the role of shielding, ground loops, as well as specifically the use of toric ferrite insolation transformer for rf noise filtering.
* K. Vodopivec et al., "High Throughput Data Acquisition with EPICS", 16th ICALEPCS, 2017, Barcelona Spain, doi: 10.18429/JACoW-ICALEPCS2017-TUBPA05
ORNL, Oak Ridge, Tennessee, USA
BNL, Upton, New York, USA
The temperature control of crystal optics is critical for ultrahigh resolution applications such as those used in meV-resolved Inelastic Scattering. Due to the low count rate and long acquisition time of these experiments, for 1-meV energy resolution, the absolute temperature stability of the crystal optics must be maintained below 4 mK to ensure the required stability of lattice constant, thereby ensuring the energy stability of the optics. Furthermore, the temperature control with sub-mK precision enables setting the absolute temperature of individual crystal, making it possible to align the reflection energy of each crystal’s rocking curve in sub-meV resolution thereby maximizing the combined efficiency of the crystal optics. In this contribution, we report the details of an EPICS control system using PT1000 sensors, Keithley 3706A 7.5 digits sensor scanner, and Wiener MPOD LV power supply for the analyzer crystals of the Inelastic X-ray Scattering (IXS) beamline 10-ID at NSLS-II**. We were able to achieve absolute temperature stability below 1 mK and sub-meV energy alignment for several asymmetrically cut analyzer crystals. The EPICS ePID record was used for the control of the power supplies based on the PT1000 sensor input that was read with 7.5 digits accuracy from the Keithley 3706A scanner. The system enhances the performance of the meV-resolved IXS spectrometer with currently a 1.4 meV total energy resolution and unprecedented spectral sharpness for studies of atomic dynamics in a broad range of materials.
