Z. Prieskorn | Pennsylvania State University (original) (raw)

Papers by Z. Prieskorn

Research paper thumbnail of Gas Gain Measurements from a Negative Ion TPC X-ray Polarimeter

Gas-based time projection chambers (TPCs) have been shown to be highly sensitive X-ray polarimete... more Gas-based time projection chambers (TPCs) have been shown to be highly sensitive X-ray polarimeters having excellent quantum efficiency while at the same time achieving large modulation factors. To observe polarization of the prompt X-ray emission of a Gamma-ray burst (GRB), a large area detector is needed. Diffusion of the electron cloud in a standard TPC could be prohibitive to measuring good modulation when the drift distance is large. Therefore, we propose using a negative ion TPC (NITPC) with Nitromethane (CH3NO2) as the electron capture agent. The diffusion of negative ions is reduced over that of electrons due to the thermal coupling of the negative ions to the surrounding gas. This allows for larger area detectors as the drift distance can be increased without degrading polarimeter modulation. Negative ions also travel ~200 times slower than electrons, allowing the readout electronics to operate slower, resulting in a reduction of instrument power. To optimize the NITPC desi...

Research paper thumbnail of ZnO thin film transistors and electronic connections for adjustable x-ray mirrors: SMART-X telescope

SPIE Proceedings, 2014

The proposed SMART-X telescope consists of a pixelated array of a piezoelectric lead zirconate ti... more The proposed SMART-X telescope consists of a pixelated array of a piezoelectric lead zirconate titanate (PZT) thin film deposited on flexible glass substrates. These cells or pixels are used to actively control the overall shape of the mirror surface. It is anticipated that the telescope will consist of 8,000 mirror panels with 400-800 cells on each panel. This creates an enormous number (6.4 million) of traces and contacts needed to address the PZT. In order to simplify the design, a row/column addressing scheme using ZnO thin film transistors (TFTs) is proposed. In addition, connection of the gate and drain lines on the mirror segment to an external supply via a flexible cable was investigated through use of an anisotropic conductive film (ACF). This paper outlines the design of the ZnO TFTs, use of ACF for bonding, and describes a specially designed electronics box with associated software to address the desired cells.

Research paper thumbnail of Gas Gain Measurements From a Negative Ion TPC X-ray Polarimeter

IEEE Transactions on Nuclear Science, 2011

Research paper thumbnail of Preprint typeset using L ATEX style emulateapj v. 10/09/06 DISCOVERY OF 1122 HZ X-RAY BURST OSCILLATIONS FROM THE NEUTRON-STAR X-RAY TRANSIENT XTE J1739-285

We report the discovery of oscillations at 1122 ± 0.3 Hz in an X-ray burst from the X-ray transie... more We report the discovery of oscillations at 1122 ± 0.3 Hz in an X-ray burst from the X-ray transient XTE J1739-285. The signal has a peak Leahy power of 42.8 and, after consideration of the number of trials, has a chance probability of occurrence of 4×10 −5, equivalent to a 4.2σ detection. The oscillation frequency suggests that XTE J1739-285 contains the fastest rotating neutron star yet found. We also found millisecond quasiperiodic oscillations in the persistent emission with frequencies ranging from 757 Hz to 862 Hz. We detected seven X-ray bursts and derive an upper limit on the source distance of about 10.6 kpc from the brightest burst. Subject headings: accretion, accretion disks — gravitation — relativity — stars: individual (XTE J1739-285) — stars: neutron — X-rays: stars 1.

Research paper thumbnail of Discovery of 1122 Hz X-Ray Burst Oscillations from the Neutron-Star X-Ray Transient XTE J1739-285

We report the discovery of oscillations at 1122 ± 0.3 Hz in an X-ray burst from the X-ray transie... more We report the discovery of oscillations at 1122 ± 0.3 Hz in an X-ray burst from the X-ray transient XTE J1739-285. The signal has a peak Leahy power of 42.8 and, after consideration of the number of trials, has a chance probability of occurrence of 4×10 −5 , equivalent to a 4.2σ detection. The oscillation frequency suggests that XTE J1739-285 contains the fastest rotating neutron star yet found. We also found millisecond quasiperiodic oscillations in the persistent emission with frequencies ranging from 757 Hz to 862 Hz. We detected seven X-ray bursts and derive an upper limit on the source distance of about 10.6 kpc from the brightest burst. 1. INTRODUCTION Weakly magnetized neutron stars can be spun up to rates of several 100 Hz by accretion in low-mass X-ray bi-naries (Alpar et al. 1982). The first direct measurements of millisecond spin rates in actively accreting neutron stars in low-mass X-ray binaries (LMXBs) came from the discovery of oscillations in thermonuclear X-ray burs...

Research paper thumbnail of Photoelectron Track Length Distributions Measured in a Negative Ion Time Projection Chamber

IEEE Transactions on Nuclear Science, 2000

We report photoelectron track length distributions between 3 and 8 keV in gas mixtures of Ne+CO 2... more We report photoelectron track length distributions between 3 and 8 keV in gas mixtures of Ne+CO 2 +CH 3 NO 2 (260:80:10 Torr) and CO 2 +CH 3 NO 2 (197.5: 15 Torr). The measurements were made using a negative ion time projection chamber (NITPC) at the National Synchrotron Light Source (NSLS) at the Brookhaven National Laboratory (BNL). We report the first quantitative analysis of photoelectron track length distributions in a gas. The distribution of track lengths at a given energy is best fit by a lognormal distribution. A powerlaw distribution of the form, f(E)=a(E/E o) n , is found to fit the relationship between mean track length and energy. We find n=1.29±0.07 for Ne+CO 2 +CH 3 NO 2 and n=1.20±0.09 for CO 2 +CH 3 NO 2. Understanding the distribution of photoelectron track lengths in proportional counter gases is important for optimizing the pixel size and the dimensions of the active region in electron-drift time projection chambers (TPCs) and NITPC Xray polarimeters. Index Terms-photoelectron track length, negative ion time projection chamber, X-ray detectors, nitromethane, CH 3 NO 2. I. INTRODUCTION maging photoelectron tracks is the key to broadband, polarization sensitive X-ray detectors. When an X-ray photoionizes an atomic s-orbital, the photoelectron is ejected according to a sin 2 θcos 2 φ probability distribution, where θ is the polar angle and φ the polarization-dependent azimuthal angle [1]. If the photoelectron track is imaged with sufficient resolution the initial direction of the photoelectron can be determined and from imaging many tracks the polarization of the incident X-rays can be measured. Multiple groups have utilized this property to build X-ray polarimeters [2]-[7]. Photoelectron track length measurements can provide a diagnostic for optimizing the pixel size, gas pressure, and the dimension of the active region in an X-ray polarimeter. The two most important detector properties that ensure the track can be accurately measured are the pixel size and the dimension of the detector active region.

Research paper thumbnail of Integrated electronics for control of large-area piezoelectric arrays for adjustable optics

Sensors and Actuators A: Physical

Research paper thumbnail of Measuring the X-ray quantum efficiency of a hybrid CMOS detector with 55Fe

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2015

Research paper thumbnail of Recent progress on developments and characterization of hybrid CMOS x-ray detectors

High Energy, Optical, and Infrared Detectors for Astronomy V, 2012

Future space-based X-ray telescope missions are likely to have significantly increased demands on... more Future space-based X-ray telescope missions are likely to have significantly increased demands on detector read out rates due to increased collection area, and there will be a desire to minimize radiation damage in the interests of maintaining spectral resolution. While CCDs have met the requirements of past missions, active pixel sensors are likely to be a standard choice for some future missions due to their inherent radiation hardness and fast, flexible read-out architecture. One form of active pixel sensor is the hybrid CMOS sensor. In a joint program of Penn State University and Teledyne Imaging Sensors, hybrid CMOS sensors have been developed for use as X-ray detectors. Results of this development effort and tests of fabricated detectors will be presented, along with potential applications for future missions.

Research paper thumbnail of <title>The GEMS photoelectric x-ray polarimeters</title>

Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray, 2010

The Gravity and Extreme Magnetism Small Explorer (GEMS) is an astrophysical observatory dedicated... more The Gravity and Extreme Magnetism Small Explorer (GEMS) is an astrophysical observatory dedicated to X-ray polarimetry (2-10 keV) and is being developed for launch in 2014. To maximize the polarization sensitivity of the observatory, GEMS uses polarimeters based on the photoelectric effect with a gas micropattern time projection chamber (TPC). We describe the TPC polarimeter concept and the details of

Research paper thumbnail of Evidence of 1122 Hz X-Ray Burst Oscillations from the Neutron Star X-Ray Transient XTE J1739-285

The Astrophysical Journal, 2007

We report on millisecond variability from the X-ray transient XTE J1739-285. We detected six X-ra... more We report on millisecond variability from the X-ray transient XTE J1739-285. We detected six X-ray type I bursts and found evidence for oscillations at 1122 ± 0.3 Hz in the brightest X-ray burst. Taking into consideration the power in the oscillations and the number of trials in the search, the detection is significant at the 99.96% confidence level. If the oscillations are confirmed, the oscillation frequency would suggest that XTE J1739-285 contains the fastest rotating neutron star yet found. We also found millisecond quasiperiodic oscillations in the persistent emission with frequencies ranging from 757 Hz to 862 Hz. Using the brightest burst, we derive an upper limit on the source distance of about 10.6 kpc.

Research paper thumbnail of Results Obtained with a Prototype Negative Ion Time Projection Chamber (NITPC) Designed for Measuring the Prompt X-ray Emission from Gamma-ray Bursts

Bulletin of the American …, 2009

Gas based time projection chambers (TPCs) have been shown to be highly sensitive X-ray polarimete... more Gas based time projection chambers (TPCs) have been shown to be highly sensitive X-ray polarimeters having excellent quantum efficiency while at the same time achieving large modulation factors . To observe polarization of the prompt X-ray emission of a Gamma-ray burst (GRB), a ...

Research paper thumbnail of ZnO thin film transistors and electronic connections for adjustable x-ray mirrors: SMART-X telescope

Adaptive X-Ray Optics III, 2014

ABSTRACT The proposed SMART-X telescope consists of a pixelated array of a piezoelectric lead zir... more ABSTRACT The proposed SMART-X telescope consists of a pixelated array of a piezoelectric lead zirconate titanate (PZT) thin film deposited on flexible glass substrates. These cells or pixels are used to actively control the overall shape of the mirror surface. It is anticipated that the telescope will consist of 8,000 mirror panels with 400-800 cells on each panel. This creates an enormous number (6.4 million) of traces and contacts needed to address the PZT. In order to simplify the design, a row/column addressing scheme using ZnO thin film transistors (TFTs) is proposed. In addition, connection of the gate and drain lines on the mirror segment to an external supply via a flexible cable was investigated through use of an anisotropic conductive film (ACF). This paper outlines the design of the ZnO TFTs, use of ACF for bonding, and describes a specially designed electronics box with associated software to address the desired cells.

Research paper thumbnail of Gas Gain Measurements from a Negative Ion TPC X-ray Polarimeter

Gas-based time projection chambers (TPCs) have been shown to be highly sensitive X-ray polarimete... more Gas-based time projection chambers (TPCs) have been shown to be highly sensitive X-ray polarimeters having excellent quantum efficiency while at the same time achieving large modulation factors. To observe polarization of the prompt X-ray emission of a Gamma-ray burst (GRB), a large area detector is needed. Diffusion of the electron cloud in a standard TPC could be prohibitive to measuring good modulation when the drift distance is large. Therefore, we propose using a negative ion TPC (NITPC) with Nitromethane (CH3NO2) as the electron capture agent. The diffusion of negative ions is reduced over that of electrons due to the thermal coupling of the negative ions to the surrounding gas. This allows for larger area detectors as the drift distance can be increased without degrading polarimeter modulation. Negative ions also travel ~200 times slower than electrons, allowing the readout electronics to operate slower, resulting in a reduction of instrument power. To optimize the NITPC desi...

Research paper thumbnail of ZnO thin film transistors and electronic connections for adjustable x-ray mirrors: SMART-X telescope

SPIE Proceedings, 2014

The proposed SMART-X telescope consists of a pixelated array of a piezoelectric lead zirconate ti... more The proposed SMART-X telescope consists of a pixelated array of a piezoelectric lead zirconate titanate (PZT) thin film deposited on flexible glass substrates. These cells or pixels are used to actively control the overall shape of the mirror surface. It is anticipated that the telescope will consist of 8,000 mirror panels with 400-800 cells on each panel. This creates an enormous number (6.4 million) of traces and contacts needed to address the PZT. In order to simplify the design, a row/column addressing scheme using ZnO thin film transistors (TFTs) is proposed. In addition, connection of the gate and drain lines on the mirror segment to an external supply via a flexible cable was investigated through use of an anisotropic conductive film (ACF). This paper outlines the design of the ZnO TFTs, use of ACF for bonding, and describes a specially designed electronics box with associated software to address the desired cells.

Research paper thumbnail of Gas Gain Measurements From a Negative Ion TPC X-ray Polarimeter

IEEE Transactions on Nuclear Science, 2011

Research paper thumbnail of Preprint typeset using L ATEX style emulateapj v. 10/09/06 DISCOVERY OF 1122 HZ X-RAY BURST OSCILLATIONS FROM THE NEUTRON-STAR X-RAY TRANSIENT XTE J1739-285

We report the discovery of oscillations at 1122 ± 0.3 Hz in an X-ray burst from the X-ray transie... more We report the discovery of oscillations at 1122 ± 0.3 Hz in an X-ray burst from the X-ray transient XTE J1739-285. The signal has a peak Leahy power of 42.8 and, after consideration of the number of trials, has a chance probability of occurrence of 4×10 −5, equivalent to a 4.2σ detection. The oscillation frequency suggests that XTE J1739-285 contains the fastest rotating neutron star yet found. We also found millisecond quasiperiodic oscillations in the persistent emission with frequencies ranging from 757 Hz to 862 Hz. We detected seven X-ray bursts and derive an upper limit on the source distance of about 10.6 kpc from the brightest burst. Subject headings: accretion, accretion disks — gravitation — relativity — stars: individual (XTE J1739-285) — stars: neutron — X-rays: stars 1.

Research paper thumbnail of Discovery of 1122 Hz X-Ray Burst Oscillations from the Neutron-Star X-Ray Transient XTE J1739-285

We report the discovery of oscillations at 1122 ± 0.3 Hz in an X-ray burst from the X-ray transie... more We report the discovery of oscillations at 1122 ± 0.3 Hz in an X-ray burst from the X-ray transient XTE J1739-285. The signal has a peak Leahy power of 42.8 and, after consideration of the number of trials, has a chance probability of occurrence of 4×10 −5 , equivalent to a 4.2σ detection. The oscillation frequency suggests that XTE J1739-285 contains the fastest rotating neutron star yet found. We also found millisecond quasiperiodic oscillations in the persistent emission with frequencies ranging from 757 Hz to 862 Hz. We detected seven X-ray bursts and derive an upper limit on the source distance of about 10.6 kpc from the brightest burst. 1. INTRODUCTION Weakly magnetized neutron stars can be spun up to rates of several 100 Hz by accretion in low-mass X-ray bi-naries (Alpar et al. 1982). The first direct measurements of millisecond spin rates in actively accreting neutron stars in low-mass X-ray binaries (LMXBs) came from the discovery of oscillations in thermonuclear X-ray burs...

Research paper thumbnail of Photoelectron Track Length Distributions Measured in a Negative Ion Time Projection Chamber

IEEE Transactions on Nuclear Science, 2000

We report photoelectron track length distributions between 3 and 8 keV in gas mixtures of Ne+CO 2... more We report photoelectron track length distributions between 3 and 8 keV in gas mixtures of Ne+CO 2 +CH 3 NO 2 (260:80:10 Torr) and CO 2 +CH 3 NO 2 (197.5: 15 Torr). The measurements were made using a negative ion time projection chamber (NITPC) at the National Synchrotron Light Source (NSLS) at the Brookhaven National Laboratory (BNL). We report the first quantitative analysis of photoelectron track length distributions in a gas. The distribution of track lengths at a given energy is best fit by a lognormal distribution. A powerlaw distribution of the form, f(E)=a(E/E o) n , is found to fit the relationship between mean track length and energy. We find n=1.29±0.07 for Ne+CO 2 +CH 3 NO 2 and n=1.20±0.09 for CO 2 +CH 3 NO 2. Understanding the distribution of photoelectron track lengths in proportional counter gases is important for optimizing the pixel size and the dimensions of the active region in electron-drift time projection chambers (TPCs) and NITPC Xray polarimeters. Index Terms-photoelectron track length, negative ion time projection chamber, X-ray detectors, nitromethane, CH 3 NO 2. I. INTRODUCTION maging photoelectron tracks is the key to broadband, polarization sensitive X-ray detectors. When an X-ray photoionizes an atomic s-orbital, the photoelectron is ejected according to a sin 2 θcos 2 φ probability distribution, where θ is the polar angle and φ the polarization-dependent azimuthal angle [1]. If the photoelectron track is imaged with sufficient resolution the initial direction of the photoelectron can be determined and from imaging many tracks the polarization of the incident X-rays can be measured. Multiple groups have utilized this property to build X-ray polarimeters [2]-[7]. Photoelectron track length measurements can provide a diagnostic for optimizing the pixel size, gas pressure, and the dimension of the active region in an X-ray polarimeter. The two most important detector properties that ensure the track can be accurately measured are the pixel size and the dimension of the detector active region.

Research paper thumbnail of Integrated electronics for control of large-area piezoelectric arrays for adjustable optics

Sensors and Actuators A: Physical

Research paper thumbnail of Measuring the X-ray quantum efficiency of a hybrid CMOS detector with 55Fe

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2015

Research paper thumbnail of Recent progress on developments and characterization of hybrid CMOS x-ray detectors

High Energy, Optical, and Infrared Detectors for Astronomy V, 2012

Future space-based X-ray telescope missions are likely to have significantly increased demands on... more Future space-based X-ray telescope missions are likely to have significantly increased demands on detector read out rates due to increased collection area, and there will be a desire to minimize radiation damage in the interests of maintaining spectral resolution. While CCDs have met the requirements of past missions, active pixel sensors are likely to be a standard choice for some future missions due to their inherent radiation hardness and fast, flexible read-out architecture. One form of active pixel sensor is the hybrid CMOS sensor. In a joint program of Penn State University and Teledyne Imaging Sensors, hybrid CMOS sensors have been developed for use as X-ray detectors. Results of this development effort and tests of fabricated detectors will be presented, along with potential applications for future missions.

Research paper thumbnail of <title>The GEMS photoelectric x-ray polarimeters</title>

Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray, 2010

The Gravity and Extreme Magnetism Small Explorer (GEMS) is an astrophysical observatory dedicated... more The Gravity and Extreme Magnetism Small Explorer (GEMS) is an astrophysical observatory dedicated to X-ray polarimetry (2-10 keV) and is being developed for launch in 2014. To maximize the polarization sensitivity of the observatory, GEMS uses polarimeters based on the photoelectric effect with a gas micropattern time projection chamber (TPC). We describe the TPC polarimeter concept and the details of

Research paper thumbnail of Evidence of 1122 Hz X-Ray Burst Oscillations from the Neutron Star X-Ray Transient XTE J1739-285

The Astrophysical Journal, 2007

We report on millisecond variability from the X-ray transient XTE J1739-285. We detected six X-ra... more We report on millisecond variability from the X-ray transient XTE J1739-285. We detected six X-ray type I bursts and found evidence for oscillations at 1122 ± 0.3 Hz in the brightest X-ray burst. Taking into consideration the power in the oscillations and the number of trials in the search, the detection is significant at the 99.96% confidence level. If the oscillations are confirmed, the oscillation frequency would suggest that XTE J1739-285 contains the fastest rotating neutron star yet found. We also found millisecond quasiperiodic oscillations in the persistent emission with frequencies ranging from 757 Hz to 862 Hz. Using the brightest burst, we derive an upper limit on the source distance of about 10.6 kpc.

Research paper thumbnail of Results Obtained with a Prototype Negative Ion Time Projection Chamber (NITPC) Designed for Measuring the Prompt X-ray Emission from Gamma-ray Bursts

Bulletin of the American …, 2009

Gas based time projection chambers (TPCs) have been shown to be highly sensitive X-ray polarimete... more Gas based time projection chambers (TPCs) have been shown to be highly sensitive X-ray polarimeters having excellent quantum efficiency while at the same time achieving large modulation factors . To observe polarization of the prompt X-ray emission of a Gamma-ray burst (GRB), a ...

Research paper thumbnail of ZnO thin film transistors and electronic connections for adjustable x-ray mirrors: SMART-X telescope

Adaptive X-Ray Optics III, 2014

ABSTRACT The proposed SMART-X telescope consists of a pixelated array of a piezoelectric lead zir... more ABSTRACT The proposed SMART-X telescope consists of a pixelated array of a piezoelectric lead zirconate titanate (PZT) thin film deposited on flexible glass substrates. These cells or pixels are used to actively control the overall shape of the mirror surface. It is anticipated that the telescope will consist of 8,000 mirror panels with 400-800 cells on each panel. This creates an enormous number (6.4 million) of traces and contacts needed to address the PZT. In order to simplify the design, a row/column addressing scheme using ZnO thin film transistors (TFTs) is proposed. In addition, connection of the gate and drain lines on the mirror segment to an external supply via a flexible cable was investigated through use of an anisotropic conductive film (ACF). This paper outlines the design of the ZnO TFTs, use of ACF for bonding, and describes a specially designed electronics box with associated software to address the desired cells.