Craig Thorn

Brookhaven National Laboratory

We report an extended measurement of the neutron cross section on argon in the energy range of 95–720 MeV. The measurement was obtained with a 4.3-hour exposure of the Mini-CAPTAIN detector to the WNR/LANSCE beam at LANL. Compared to an earlier analysis of the same data, this extended analysis includes a reassessment of systematic uncertainties, in...

We report an extended measurement of the neutron cross section on argon in the energy range of 95-720 MeV. The measurement was obtained with a 4.3-hour exposure of the Mini-CAPTAIN detector to the WNR/LANSCE beam at LANL. Compared to an earlier analysis of the same data, this extended analysis includes a reassessment of systematic uncertainties, in...

The ability of free electrons to drift long distances at high velocities in pure liquid argon under an applied electric field has been exploited for the past forty years to implement detectors with increasingly large volumes for high energy physics research. In this paper, we summarize the electron attachment rate constants as a function of the ext...

A number of critical active and passive components of optical links have been tested at 77 K or lower temperatures, demonstrating potential development of optical links operating inside the liquid argon time projection chamber (LArTPC) detector cryostat. A ring oscillator, individual MOSFETs, and a high speed 16:1 serializer fabricated in a commerc...

This manuscript describes the commissioning of the Mini-CAPTAIN liquid argon detector in a neutron beam at the Los Alamos Neutron Science Center (LANSCE), which led to a first measurement of high-energy neutron interactions in argon. The Mini-CAPTAIN detector consists of a Time Projection Chamber (TPC) with an accompanying photomultiplier tube (PMT...

Impurities in noble liquid detectors used for neutrino and dark mater experiments can significantly impact the quality of data. We present an experimentally verified model for describing the dynamics of impurity distributions in liquid argon (LAr) detectors. The model considers sources, sinks, and transport of impurities within and between the gas...

This manuscript describes the commissioning of the Mini-CAPTAIN liquid argon detector in a neutron beam at the Los Alamos Neutron Science Center (LANSCE), which led to a first measurement of high-energy neutron interactions in argon. The Mini-CAPTAIN detector consists of a Time Projection Chamber (TPC) with an accompanying photomultiplier tube (PMT...

We report the first measurement of the neutron cross section on argon in the energy range of 100–800 MeV. The measurement was obtained with a 4.3-h exposure of the Mini-CAPTAIN detector to the WNR/LANSCE beam at LANL. The total cross section is measured from the attenuation coefficient of the neutron flux as it traverses the liquid argon volume. A...

Background: Emergency abdominal surgery is associated with poor patient outcomes. We studied the effectiveness of a national quality improvement (QI) programme to implement a care pathway to improve survival for these patients. Methods: We did a stepped-wedge cluster-randomised trial of patients aged 40 years or older undergoing emergency open m...

We report the first measurement of the neutron cross section on argon in the energy range of 100-800 MeV. The measurement was obtained with a 4.3-hour exposure of the Mini-CAPTAIN detector to the WNR/LANSCE beam at LANL. The total cross section is measured from the attenuation coefficient of the neutron flux as it traverses the liquid argon volume....

We describe the concept and procedure of drifted-charge extraction developed in the MicroBooNE experiment, a single-phase liquid argon time projection chamber (LArTPC). This technique converts the raw digitized TPC waveform to the number of ionization electrons passing through a wire plane at a given time. A robust recovery of the number of ionizat...

ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in it...

ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in it...

The low-noise operation of readout electronics in a liquid argon time projection chamber (LArTPC) is critical to properly extract the distribution of ionization charge deposited on the wire planes of the TPC, especially for the induction planes. This paper describes the characteristics and mitigation of the observed noise in the MicroBooNE detector...

This paper describes the design and construction of the MicroBooNE liquid argon time projection chamber and associated systems. MicroBooNE is the first phase of the Short Baseline Neutrino program, located at Fermilab, and will utilize the capabilities of liquid argon detectors to examine a rich assortment of physics topics. In this document detail...

We describe the design of a 20-liter test stand constructed to study fundamental properties of liquid argon (LAr). This system utilizes a simple, cost-effective gas argon (GAr) purification to achieve ultra-high purity, which is necessary to study electron transport properties in LAr. An electron drift stack with up to 25 cm length is constructed t...

This document presents the Conceptual Design Report (CDR) put forward by an international neutrino community to pursue the Deep Underground Neutrino Experiment at the Long-Baseline Neutrino Facility (LBNF/DUNE), a groundbreaking science experiment for long-baseline neutrino oscillation studies and for neutrino astrophysics and nucleon decay searche...

The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described.

We report the measurement of longitudinal electron diffusion coefficients in liquid argon for electric fields between 100 and 2000 V/cm with a gold photocathode as a bright electron source. The measurement principle, apparatus, and data analysis are described. Our results, which are consistent with previous measurements in the region between 100 to...

The second workshop to discuss the development of liquid argon time projection chambers (LArTPCs) in the United States was held at Fermilab on July 8-9, 2014. The workshop was organized under the auspices of the Coordinating Panel for Advanced Detectors, a body that was initiated by the American Physical Society Division of Particles and Fields. Al...

The second workshop to discuss the development of liquid argon time projection chambers (LArTPCs) in the United States was held at Fermilab on July 8-9, 2014. The workshop was organized under the auspices of the Coordinating Panel for Advanced Detectors, a body that was initiated by the American Physical Society Division of Particles and Fields. Al...

A Short-Baseline Neutrino (SBN) physics program of three LAr-TPC detectors located along the Booster Neutrino Beam (BNB) at Fermilab is presented. This new SBN Program will deliver a rich and compelling physics opportunity, including the ability to resolve a class of experimental anomalies in neutrino physics and to perform the most sensitive searc...

A device has been developed with moveable liquid nitrogen and liquid helium volumes that is capable of reaching over 2 m into the coldest regions of a cryostat or dilution refrigerator and reliably extracting or installing a target of solid, polarized hydrogen deuteride (HD). This Transfer Cryostat incorporates a cylindrical neodymium rare-earth ma...

These reports present the results of the 2013 Community Summer Study of the APS Division of Particles and Fields ("Snowmass 2013") on the future program of particle physics in the U.S. Chapter 8, on the Instrumentation Frontier, discusses the instrumentation needs of future experiments in the Energy, Intensity, and Cosmic Frontiers, promising new t...

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and...

This white paper describes LAr1-ND and the compelling physics it brings first in Phase 1 and next towards the full LAr1 program. In addition, LAr1-ND serves as a key step in the development toward large-scale LArTPC detectors. Its development goals will encompass testing existing and possibly innovative designs for LBNE while at the same time provi...

The Cryogenic Apparatus for Precision Tests of Argon Interactions with Neutrino (CAP- TAIN) program is designed to make measurements of scientific importance to long-baseline neutrino physics and physics topics that will be explored by large underground detectors. The CAPTAIN detector is a liquid argon TPC deployed in a portable and evacuable cryos...

A workshop was held at Fermilab on March 20-21, 2013 to discuss the development of liquid argon time projection chambers (LArTPC) in the United States. The workshop was organized under the auspices of the Coordinating Panel for Advanced Detectors, a body that was initiated by the American Physical Society Division of Particles and Fields. All prese...

In this document, we describe the wealth of science opportunities and capabilities of LBNE, the Long-Baseline Neutrino Experiment. LBNE has been developed to provide a unique and compelling program for the exploration of key questions at the forefront of particle physics. Chief among the discovery opportunities are observation of CP symmetry violat...

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and...

Liquid argon time projection chamber (LArTPC) is a unique technology well suited for large scale detectors of neutrinos and other rare processes. Its combination of millimeter scale 3D precision particle tracking and calorimetry with good dE/dx resolution provide excellent efficiency of particle identification and background rejection. MicroBooNE i...

The LBNE Project is developing a design for multiple 20 kiloton liquid argon (LAr) time projection chambers to be used as the far detector for the Long Baseline Neutrino Experiment. An essential component of this design is a complete electronic readout system designed to operate in LAr (at 90K). This system is being implemented as a CMOS ASIC, in 1...

MicroBooNE experiment is to build a similar to 170 tons Liquid Argon (LAr) Time Projection Chamber (TPC) detector that will observe interactions of neutrinos from the on-axis Booster Neutrino Beam and off-axis NuMI Beam at Fermi National Accelerator Laboratory. The experiment will address the low energy excess observed by the MiniBooNE experiment,...

MicroBooNE experiment will use a ~ 100 ton Liquid Argon (LAr) Time Projection Chamber (TPC) detector, presently under construction, to observe interactions of neutrinos from the on-axis Booster Neutrino Beam and off-axis NuMI Beam at Fermi National Accelerator Laboratory. The experiment will address the low energy excess observed by the MiniBooNE e...

The Proceedings of the 2011 workshop on Fundamental Physics at the Intensity Frontier. Science opportunities at the intensity frontier are identified and described in the areas of heavy quarks, charged leptons, neutrinos, proton decay, new light weakly-coupled particles, and nucleons, nuclei, and atoms.

In early 2010, the Long-Baseline Neutrino Experiment (LBNE) science collaboration initiated a study to investigate the physics potential of the experiment with a broad set of different beam, near- and far-detector configurations. Nine initial topics were identified as scientific areas that motivate construction of a long-baseline neutrino experimen...

The choice between cold and warm electronics (inside or outside the cryostat) in very large LAr TPCs (>5-10 ktons) is not an electronics issue, but it is rather a major cryostat design issue. This is because the location of the signal processing electronics has a direct and far reaching effect on the cryostat design, an indirect effect on the TPC e...

Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation Rev. Sci. Instrum. 83, 02B727 (2012) Novel methods for improvement of a Penning ion source for neutron generator applications Rev. Sci. Instrum. 83, 02B309 (2012) Use of a wire scanner for monitoring residual gas ionization in Soreq Applied Research Accel...

The choice between cold and warm electronics (inside or outside the cryostat) in very large LAr TPCs (>5-10 ktons) is not an electronics issue, but it is rather a major cryostat design issue. This is because the location of the signal processing electronics has a direct and far reaching effect on the cryostat design, an indirect effect on the TPC e...

A number of critical active and passive components of optical links have been tested at 77 K or lower temperatures, demonstrating potential development of optical links operating inside the liquid argon time projection chamber (LArTPC) detector cryostat. A ring oscillator, individual MOSFETs, and a high speed 16:1 serializer fabricated in a co...

We introduce a front-end application specific integrated circuit (ASIC) for a wire based Time-Projection-Chamber (TPC) operating in liquid Argon (LAr). The LAr TPC will be used for long baseline neutrino oscillation experiments. The ASIC must provide low-noise readout of the signals induced on the TPC wires, digitization of those signals at 2 MS/s,...

The extraction of resonance parameters from meson photo-reaction data is a challenging effort, that would greatly benefit from the availability of several polarization observables, measured for each reaction channel on both proton and neutron targets. In the aim of obtaining such complete experiments, polarized photon beams and targets have been de...

We have constructed and operated a NMR polarimeter for high-accuracy measurements of hydrogen and deuterium polarization in a frozen-spin solid HD photonuclear physics target. The heart of this polarimeter is a pair of crossed (orthogonal) RF coils that form a transformer that responds only to precessing spins in the sample. We have performed a com...

We report new measurements of inclusive pi production from frozen-spin HD for polarized photon beams covering the Delta(1232) resonance. These provide data simultaneously on both H and D with nearly complete angular distributions of the spin-difference cross sections entering the Gerasimov-Drell-Hearn (GDH) sum rule. Recent results from Mainz and B...

There are many potentially interesting 12 GeV-era electron experiments that require transversely polarized H or D. The high fields associated with conventional Dynamically Polarized targets lead to challenging background conditions if oriented transverse to an electron beam. Frozen-spin targets that are maintained by low holding fields could greatl...

We have developed a precision NMR polarimeter to observe the proton and deuteron polarization of a frozen spin HD target used in photoproduction experiments at the LEGS facility. This polarimeter uses a pair of magnetically orthogonal (“crossed”) RF coils to reduce the signal to very small levels in the absence of polarization of the sample. This...

A compact time projection chamber (TPC) has been constructed for the LEGS (Laser Electron Gamma Source) experiment at BNL. The TPC uses double GEMs as the amplification stage. Position encoding is achieved through charge division using zigzag shaped anode pads. The TPC has a 35 cm diameter active area and a 50 cm long drift depth. It has more than...

A time projection chamber for experiments with the laser electron gamma source is being developed. It is composed of a can and a single-ended, dual-stage gas electron multiplier, with associated anode plane pixellated into about 8000 pads. The front-end electronics must provide energy, timing, and address information from those pads involved in mea...

Double polarization experiments at the Laser Electron Gamma Source (LEGS) at Brookhaven National Laboratory have been performed with polarized photon beams and a polarized Hydrogen Deuteride (HD) frozen spin target. After polarizing at 15 T and 17 mK and subsequently reaching a frozen spin mode, a target was cold extracted (at 2:5 K and 0:016 T) an...

A solid, polarized HD target has been developed for the measurement of double-polarization observables in the Delta resonance region. The focus of the experimental program is a comparison of pion photo-production amplitudes for the neutron and proton and the associated spin-dependent sum rules.

Differential cross sections and beam asymmetries of Compton scattering from 4He have been measured with linearly polarized photons in the energy range from 206 to 310 MeV. The quality of the results has the potential to provide strong constraints on the understanding of the reaction mechanism in the Δ resonance region. A phenomenological analysis o...

A Time Projection Chamber for experiments with the Laser Electron Gamma Source is being developed. It is composed of a can and a single-ended, dual-stage Gas Electron Multiplier, with associated anode plane pixellated into about eight thousand pads. The front-end electronics must provide energy, timing and address information from those pads involv...

The performance of statically polarized high‐field/low‐temperature targets is a strong function of the base temperature during polarization. At the Laser‐Electron Gamma Source (LEGS) facility, highly polarized Hydrogen Deuteride targets are created in a dilution refrigerator/15 tesla superconducting magnet system, and converted to a frozen spin sta...

The first experiments have been carried out with polarized HD targets at the Laser-Electron-Gamma-Source (LEGS) facility. By holding targets at low temperature and high field (17 mK and 15 Tesla) in a Dilution Refrigerator (DF) for six weeks a frozen-spin state was reached, with equilibrium polarizations for protons and deuterons of 70% and 17%, re...

We have performed a complete electronic circuit analysis of the crossed coil NMR polarimeter (CC‐meter), and from this analysis we have determined the optimum conditions for its operation. From this analysis, which is confirmed by NMR measurements on hydrogen, we conclude that the CC‐meter can be operated to give a very high signal‐to‐noise rati...

The LEGS facility provides a tagged, polarized (linear or circular) gamma ray beam. A target consisting of frozen HD that can have independent polarizations for the free and bound nucleons is under production. Double polarization experiments of pion photo-production and nucleon-Compton scattering will allow measurements of various nucleon structure...

We report new high-precision measurements of p(γ-->,γ), p(γ-->,π0) and p(γ-->,π+) cross section and beam asymmetry angular distributions for photon beam energies in the range from 213 MeV to 333 MeV. The cross sections for all three channels are locked together with a small common systematic scale uncertainty of 2%. A large overdetermination of kin...

DOI:https://doi.org/10.1103/PhysRevC.64.029902

Summary form only given. We have developed a frequency quadrupled Nd:YLF laser as a source of photons to Compton backscatter from a beam of electrons circulating in a storage ring. The laser beam must be transported 22 meters to the interaction region in the synchrotron and the mode at that point must be matched to the electron beam. Unfortunately,...

Cross sections are presented for the 16O(γ +(combining right arrow above),π-p) reaction at incident photon energies between 290 and 325 MeV. The data are presented for specific proton and pion angles as a function of proton energy, which are compared with calculations in a local distorted wave impulse approximation model. The results are in agreeme...

Cross sections are presented for the O-16(<(gamma)over right arrow>, pi(-) p) reaction at incident photon energies between 290 and 325 MeV. The data are presented for specific proton and pion angles as a function of proton energy, which are compared with calculations in a local distorted wave impulse approximation model. The results are in agree me...

Cross sections are presented for the 16O(γ⃗,π-p) reaction at incident photon energies between 290 and 325 MeV. The data are presented for specific proton and pion angles as a function of proton energy, which are compared with calculations in a local distorted wave impulse approximation model. The results are in agreement at most kinematics, althoug...

The photodisintegration of deuterium with linearly polarized light has been measured in the energy range of 110-315 MeV. The results of five independent measurements using three detector systems, two liquid target,geometries, and two photon energy distribution end points are presented. These data are combined into one average data set with a system...

form only given. We have constructed a single ring to resonantly double an 18-W Nd:YLF mode-locked laser and re-double the stored green beam to produce a nearly-diffraction-limited ultraviolet (UV) beam of 4.2 W at 263 nm. The IR output of the pump laser is coupled to the slave cavity via a mode-matching telescope, which produces a waist inside the...

The authors have constructed a single ring to resonantly double an 18 watt Nd:YLF mode-locked laser and re-double the stored green to produce over 4 watts of power in the ultra-violet (UV). This laser is used to produce a beam of 470 MeV gamma-rays by Compton backscattering the laser beam from 2.8 GeV electrons stored in a synchrotron. Achieving hi...

110 ffi and 130 ffi for incoming photon energies of 206, 219, 232, 245, 259, 274, 289, 306 and 322 MeV. The unpolarized cross sections are compared with the Delta Gamma hole theoretical model results available in literature. The measured photon beam asymmetry is Gamma1 as expected from conservation of angular momentum and parity. PACS: 25.20 D, 24....

New high-precision measurements of p(, π) and p(, γ) cross sections and beam asymmetries have been combined with other polarization ratios in a simultaneous analysis of both reactions. Compton scattering has provided two important new constraints on the photo-pion amplitude. The E2/M1 mixing ratio for the N → Δ transition extracted from this analys...

New high-precision measurements of p({rvec {gamma}},{pi}) and p({rvec {gamma}},{gamma}) cross sections and beam asymmetries have been combined with other polarization ratios in a simultaneous analysis of both reactions. Compton scattering has provided two important new constraints on the photopion amplitude. The E2/M1 mixing ratio for the N{r_arrow...

New high-precision measurements of p(γ[over →],π) and p(γ[over →],γ) cross sections and beam asymmetries have been combined with other polarization ratios in a simultaneous analysis of both reactions. Compton scattering has provided two important new constraints on the photopion amplitude. The E2/M1 mixing ratio for the N→Δ transition extracted fro...

Spin asymmetries for the 16O(γ⃗,pπ-) reaction are reported for incident photon energies of 293 ± 20 MeV, proton angles ranging from 28° to 140° (lab), and pion angles of 35° to 115°. The data are compared with calculations in a quasifree plane-wave impulse approximation model. This model is in good agreement with the data at small momentum transfer...

New precision measurements of cross sections and polarization asymmetries in the p\(gamma-->,gammap\) reaction at 90° c.m. are presented for incident energies between 213 and 333 MeV. A long-standing problem with earlier experiments that appeared to violate unitarity at the peak of the Delta is resolved. Data are compared to theories based on baryo...

New precision measurements of the 2H(γ→,p)n reaction taken with tagged polarized photons, and covering a wide angular range, are presented for incident energies between 113 and 315 MeV. In the region of the Δ resonance, the photodisintegration observables can potentially be used to probe the NΔ interaction. Coupled-channel calculations are in agree...