Publications by Jaya John John

Radiation hardness studies of AMS HV-CMOS 350 nm prototype chip HVStripV1

Journal of Instrumentation IOP Publishing 12 (2017) P02010-

K Kanisauskas, A Affolder, K Arndt, R Bates, M Benoit, FD Bello, A Blue, D Bortoletto, M Buckland, C Buttar, P Caragiulo, D Das, J Dopke, A Dragone, F Ehrler, V Fadeyev, Z Galloway, H Grabas, IM Gregor, P Grenier, A Grillo, B Hiti, M Hoeferkamp, LBA Hommels, BT Huffman

CMOS active pixel sensors are being investigated for their potential use in the ATLAS inner tracker upgrade at the HL-LHC. The new inner tracker will have to handle a significant increase in luminosity while maintaining a sufficient signal-to-noise ratio and pulse shaping times. This paper focuses on the prototype chip "HVStripV1" (manufactured in the AMS HV-CMOS 350nm process) characterization before and after irradiation up to fluence levels expected for the strip region in the HL-LHC environment. The results indicate an increase of depletion region after irradiation for the same bias voltage by a factor of ≈2.4 and ≈2.8 for two active pixels on the test chip. There was also a notable increase in noise levels from 85 e− to 386 e− and from 75 e− to 277 e− for the corresponding pixels.

Radiation hardness of two CMOS prototypes for the ATLAS HL-LHC upgrade project


BT Huffman, A Affolder, K Arndt, R Bates, M Benoit, F Di Bello, A Blue, D Bortoletto, M Buckland, C Buttar, P Caragiulo, D Das, J Dopke, A Dragone, F Ehrler, V Fadeyev, Z Galloway, H Grabas, IM Gregor, P Grenier, A Grillo, M Hoeferkamp, LBA Hommeis, J John, K Kanisauskas, C Kenney, J Kramberger, Z Liang, I Mandic, D Maneuski, F Martinez-Mckinney, S McMahon, L Meng, M Mikuz, D Muenstermann, R Nickerson, I Peric, P Phillips, R Plackett, F Rubbo, J Segal, S Seidel, A Seiden, I Shipsey, W Song, M Stanitzki, D Su, C Tamma, R Turchetta, L Vigani, J Volk, R Wang, M Warren, F Wilson, S Worm, Q Xiu, J Zhang, H Zhu

'GP2' - An energy resolved neutron imaging detector using a Gd coated CMOS sensor

2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015 IEEE (2016)

DE Pooley, JWL Lee, M Brouard, R Farrow, J John, W Kockelmann, RB Nickerson, NJ Rhodes, EM Schooneveld, I Sedgwick, R Turchetta, C Vallance

This paper documents the R&D; undertaken jointly by the ISIS Neutron Detector Group and the Oxford University PImMS collaboration. The aim of this project was to develop a high resolution, energy resolved, neutron imaging detector named GP2. This conference record introduces the GP2 detector and lists its key physical properties; however the emphasis here will be on the earlier proof-of-principle work performed with both gadolinium thin films and thick rolled sheets with the prototype PImMS1 sensor and the larger PImMS2 sensor.

Charge collection studies in irradiated HV-CMOS particle detectors

Journal of Instrumentation IOP Publishing 11 (2016) P04007-P04007

A Affolder, M Andelković, K Arndt, C Buttar, P Caragiulo, V Cindro, D Das, J Dopke, A Dragone, F Ehrler, V Fadeyev, Z Galloway, H Grabas, IM Gregor, P Grenier, A Grillo, LBA Hommels, B Huffman, K Kanisauskas, C Kenney, G Kramberger, S McMahon, M Mikuž, R Nickerson, I Perić

Charge collection properties of particle detectors made in HV-CMOS technology were investigated before and after irradiation with reactor neutrons. Two different sensor types were designed and processed in 180 and 350 nm technology by AMS. Edge-TCT and charge collection measurements with electrons from 90Sr source were employed. Diffusion of generated carriers from undepleted substrate contributes significantly to the charge collection before irradiation, while after irradiation the drift contribution prevails as shown by charge measurements at different shaping times. The depleted region at a given bias voltage was found to grow with irradiation in the fluence range of interest for strip detectors at the HL-LHC. This leads to large gains in the measured charge with respect to the one before irradiation. The increase of the depleted region was attributed to removal of effective acceptors. The evolution of depleted region with fluence was investigated and modeled. Initial studies show a small effect of short term annealing on charge collection.

Study of built-in amplifier performance on HV-CMOS sensor for the ATLAS phase-II strip tracker upgrade

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Elsevier 831 (2016) 156-160

Z Liang, A Affolder, K Arndt, R Bates, M Benoit, F Di Bello, A Blue, D Bortoletto, M Buckland, C Buttar, P Caragiulo, D Das, J Dopke, A Dragone, F Ehrler, V Fadeyev, Z Galloway, H Grabas, IM Gregor, P Grenier, A Grillo, R Turchetta, L Vigani, J Volk, R Wang

This paper focuses on the performance of analog readout electronics (built-in amplifier) integrated on the high-voltage (HV) CMOS silicon sensor chip, as well as its radiation hardness. Since the total collected charge from minimum ionizing particle (MIP) for the CMOS sensor is 10 times lower than for a conventional planar sensor, it is crucial to integrate a low noise built-in amplifier on the sensor chip to improve the signal to noise ratio of the system. As part of the investigation for the ATLAS strip detector upgrade, a test chip that comprises several pixel arrays with different geometries, as well as standalone built-in amplifiers and built-in amplifiers in pixel arrays has been fabricated in a 0.35 μm high-voltage CMOS process. Measurements of the gain and the noise of both the standalone amplifiers and built-in amplifiers in pixel arrays were performed before and after gamma radiation of up to 60 Mrad. Of special interest is the variation of the noise as a function of the sensor capacitance. We optimized the configuration of the amplifier for a fast rise time to adapt to the LHC bunch crossing period of 25 ns, and measured the timing characteristics including jitter. Our results indicate an adequate amplifier performance for monolithic structures used in HV-CMOS technology. The results have been incorporated in the next submission of a large-structure chip.

Investigation of HV/HR-CMOS technology for the ATLAS Phase-II Strip Tracker Upgrade


V Fadeyev, Z Galloway, H Grabas, AA Grillo, Z Liang, F Martinez-Mckinney, A Seiden, J Volk, A Affolder, M Buckland, L Meng, K Arndt, D Bortoletto, T Huffman, J John, S McMahon, R Nickerson, P Phillips, R Plackett, I Shipsey, L Vigani, R Bates, A Blue, C Buttar, K Kanisauskas, D Maneuski, M Benoit, F Di Bello, P Caragiulo, A Dragone, P Grenier, C Kenney, F Rubbo, J Segal, D Su, C Tamma, D Das, J Dopke, R Turchetta, F Wilson, S Worm, F Ehrler, I Peric, IM Gregor, M Stanitzki, M Hoeferkamp, S Seidel, LBA Hommels, G Kramberger, I Mandic, M Mikuz, D Muenstermann, R Wang, J Zhang, M Warren, W Song, Q Xiu, H Zhu

The C-Band all-sky survey (C-BASS): Design and implementation of the Northern receiver

Monthly Notices of the Royal Astronomical Society 438 (2014) 2426-2439

OG King, ME Jones, EJ Blackhurst, C Copley, RJ Davis, C Dickinson, CM Holler, MO Irfan, JJ John, JP Leahy, J Leech, SJC Muchovej, TJ Pearson, MA Stevenson, AC Taylor

The C-Band All-Sky Survey is a project to map the full sky in total intensity and linear polarization at 5 GHz. The northern component of the survey uses a broad-band singlefrequency analogue receiver fitted to a 6.1-m telescope at the Owens Valley Radio Observatory in California, USA. The receiver architecture combines a continuous-comparison radiometer and a correlation polarimeter in a single receiver for stable simultaneous measurement of both total intensity and linear polarization, using custom-designed analogue receiver components. The continuous-comparison radiometer measures the temperature difference between the sky and temperature-stabilized cold electrical reference loads. A cryogenic front-end is used to minimize receiver noise, with a system temperature of ≈30K in both linear polarization and total intensity.Custom cryogenic notch filters are used to counteract man-made radio frequency interference. The radiometer 1/f noise is dominated by atmospheric fluctuations, while the polarimeter achieves a 1/f noise knee frequency of 10 mHz, similar to the telescope azimuthal scan frequency. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Modifications to a commercially available linear mass spectrometer for mass-resolved microscopy with the pixel imaging mass spectrometry (PImMS) camera

Rapid Communications in Mass Spectrometry 28 (2014) 1649-1657

E Halford, B Winter, MD Mills, SP Thompson, V Parr, JJ John, A Nomerotski, C Vallance, R Turchetta, M Brouard

RATIONALE Imaging mass spectrometry is a powerful analytical technique capable of accessing a large volume of spatially resolved, chemical data from two-dimensional samples. Probing the entire surface of a sample simultaneously requires a detector with high spatial and temporal resolutions, and the ability to observe events relating to different mass-to-charge ratios. METHODS A commercially available time-of-flight mass spectrometer, designed for matrix-assisted laser desorption/ionization (MALDI) analysis, was combined with the novel pixel imaging mass spectrometry (PImMS) camera in order to perform multi-mass, microscope-mode imaging experiments. A number of minor modifications were made to the spectrometer hardware and ion optics so that spatial imaging was achieved for a number of small molecules. RESULTS It was shown that a peak width of Δm50% < 1 m/z unit across the range 200 ≤ m/z ≤ 800 can be obtained while also achieving an optimum spatial resolution of 25 μm. It was further shown that these data were obtained simultaneously for all analytes present without the need to scan the experimental parameters. CONCLUSIONS This work demonstrates the capability of multi-mass, microscope-mode imaging to reduce the acquisition time of spatially distributed analytes such as multi-arrays or biological tissue sections. It also shows that such an instrument can be commissioned by effecting relatively minor modifications to a conventional commercial machine. Copyright © 2014 John Wiley & Sons, Ltd.

Covariance imaging experiments using a pixel-imaging mass-spectrometry camera

Physical Review A - Atomic, Molecular, and Optical Physics 89 (2014)

CS Slater, S Blake, M Brouard, A Lauer, C Vallance, JJ John, R Turchetta, A Nomerotski, L Christensen, JH Nielsen, MP Johansson, H Stapelfeldt

The "pixel imaging mass spectrometry" camera is used to perform femtosecond laser-induced Coulomb explosion imaging of 3,5-dibromo-3′, 5′-difluoro-4′-cyanobiphenyl molecules prealigned in space. The experiment allows the concurrent detection of the correlated two-dimensional momentum images of all the ionic fragments resulting from fragmentation of multiple molecules in each acquisition cycle. The Coulomb explosion studies provide rich information about the parent molecular structure and fragmentation dynamics, and open new opportunities for real-time imaging of intramolecular processes. © 2014 American Physical Society.

Fast sensors for time-of-flight imaging applications.

Physical chemistry chemical physics : PCCP Royal Society of Chemistry 16 (2014) 383-395

C Vallance, M Brouard, A Lauer, CS Slater, E Halford, B Winter, SJ King, JW Lee, DE Pooley, I Sedgwick, R Turchetta, A Nomerotski, JJ John, L Hill

The development of sensors capable of detecting particles and radiation with both high time and high positional resolution is key to improving our understanding in many areas of science. Example applications of such sensors range from fundamental scattering studies of chemical reaction mechanisms through to imaging mass spectrometry of surfaces, neutron scattering studies aimed at probing the structure of materials, and time-resolved fluorescence measurements to elucidate the structure and function of biomolecules. In addition to improved throughput resulting from parallelisation of data collection - imaging of multiple different fragments in velocity-map imaging studies, for example - fast image sensors also offer a number of fundamentally new capabilities in areas such as coincidence detection. In this Perspective, we review recent developments in fast image sensor technology, provide examples of their implementation in a range of different experimental contexts, and discuss potential future developments and applications.

Exploring surface photoreaction dynamics using pixel imaging mass spectrometry (PImMS)

Journal of Chemical Physics 139 (2013)

MD Kershis, DP Wilson, MG White, JJ John, A Nomerotski, M Brouard, JWL Lee, C Vallance, R Turchetta

A new technique for studying surface photochemistry has been developed using an ion imaging time-of-flight mass spectrometer in conjunction with a fast camera capable of multimass imaging. This technique, called pixel imaging mass spectrometry (PImMS), has been applied to the study of butanone photooxidation on TiO(110). In agreement with previous studies of this system, it was observed that the main photooxidation pathway for butanone involves ejection of an ethyl radical into vacuum which, as confirmed by our imaging experiment, undergoes fragmentation after ionization in the mass spectrometer. This proof-of-principle experiment illustrates the usefulness and applicability of PImMS technology to problems of interest within the surface science community. © 2013 AIP Publishing LLC.

PImMS, a fast event-triggered monolithic pixel detector with storage of multiple timestamps

Journal of Instrumentation 7 (2012)

J John, M Brouard, A Clark, J Crooks, E Halford, L Hill, L Lee, A Nomerotski, R Pisarczyk, I Sedgwick, S Slater, R Turchetta, C Vallance, E Wilman, B Winter, H Yuen

PImMS, or Pixel Imaging Mass Spectrometry, is a novel high-speed monolithic CMOS imaging sensor tailored to mass spectrometry requirements, also suitable for other dark-field applications. In its application to time-of-flight mass spectrometry, the sensor permits ion arrival time distributions to be combined with 2D imaging, providing additional information about the initial position or velocity of ions under study. PImMS1, the first generation sensor in this family, comprises an array of 72 by 72 pixels on a 70 μm by 70 μm pitch. Pixels independently record digital timestamps when events occur over an adjustable threshold. Each pixel contains 4 memories to record timestamps at a resolution of 25 ns. The sensor was designed and manufactured in the INMAPS 0.18 μm process. This allows the inclusion of significant amounts of circuitry (over 600 transistors) within each pixel while maintaining good detection efficiency. We present an overview of the pixel and sensor architecture, explain its functioning and present test results, ranging from characterisation of the analogue front end of the pixel, to verification of its digital functions, to some first images captured on mass spectrometers. We conclude with an overview of the upcoming second generation of PImMS sensors. © 2012 IOP Publishing Ltd and Sissa Medialab srl.

PImMS: A self-triggered, 25ns resolution monolithic CMOS sensor for Time-of-Flight and Imaging Mass Spectrometry

2012 IEEE 10th International New Circuits and Systems Conference, NEWCAS 2012 (2012) 497-500

I Sedgwick, A Clark, J Crooks, R Turchetta, L Hill, JJ John, A Nomerotski, R Pisarczyk, M Brouard, SH Gardiner, E Halford, J Lee, ML Lipciuc, C Slater, C Vallance, ES Wilman, B Winter, WH Yuen

In this paper, we present the Pixel Imaging Mass Spectrometry (PImMS) sensor, a pixelated Time-of-Flight (TOF) sensor for use in mass spectrometry. The device detects any event which produces a signal above a programmable threshold with a timing resolution of 25ns. Both analogue and digital readout modes are available and all pixels can be individually trimmed to improve noise performance. The pixels themselves contain analogue signal conditioning circuitry as well as complex logic totalling more than 600 transistors. This large number can be achieved without any loss of quantum efficiency thanks to the use of the patented Isolated N-well Monolithic Active Pixels (INMAPS) process. In this paper, we examine the design of the PImMS 1.0 device and its successor PImMS 2.0, a significantly enlarged sensor with several added features. We will also present some initial results from mass spectrometry experiments performed with PImMS 1.0. © 2012 IEEE.

Multimass velocity-map imaging with the Pixel Imaging Mass Spectrometry (PImMS) sensor: an ultra-fast event-triggered camera for particle imaging.

J Phys Chem A 116 (2012) 10897-10903

AT Clark, JP Crooks, I Sedgwick, R Turchetta, JWL Lee, JJ John, ES Wilman, L Hill, E Halford, CS Slater, B Winter, WH Yuen, SH Gardiner, ML Lipciuc, M Brouard, A Nomerotski, C Vallance

We present the first multimass velocity-map imaging data acquired using a new ultrafast camera designed for time-resolved particle imaging. The PImMS (Pixel Imaging Mass Spectrometry) sensor allows particle events to be imaged with time resolution as high as 25 ns over data acquisition times of more than 100 μs. In photofragment imaging studies, this allows velocity-map images to be acquired for multiple fragment masses on each time-of-flight cycle. We describe the sensor architecture and present bench-testing data and multimass velocity-map images for photofragments formed in the UV photolysis of two test molecules: Br(2) and N,N-dimethylformamide.

The application of the fast, multi-hit, pixel imaging mass spectrometry sensor to spatial imaging mass spectrometry.

Rev Sci Instrum 83 (2012) 114101-

M Brouard, E Halford, A Lauer, CS Slater, B Winter, WH Yuen, JJ John, L Hill, A Nomerotski, A Clark, J Crooks, I Sedgwick, R Turchetta, JWL Lee, C Vallance, E Wilman

Imaging mass spectrometry is a powerful technique that allows chemical information to be correlated to a spatial coordinate on a sample. By using stigmatic ion microscopy, in conjunction with fast cameras, multiple ion masses can be imaged within a single experimental cycle. This means that fewer laser shots and acquisition cycles are required to obtain a full data set, and samples suffer less degradation as overall collection time is reduced. We present the first spatial imaging mass spectrometry results obtained with a new time-stamping detector, named the pixel imaging mass spectrometry (PImMS) sensor. The sensor is capable of storing multiple time stamps in each pixel for each time-of-flight cycle, which gives it multi-mass imaging capabilities within each pixel. A standard velocity-map ion imaging apparatus was modified to allow for microscope mode spatial imaging of a large sample area (approximately 5 × 5 mm(2)). A variety of samples were imaged using PImMS and a conventional camera to determine the specifications and possible applications of the spectrometer and the PImMS camera.

Design and performance of improved Column Parallel CCD, CPC2

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 621 (2010) 192-204

Y Banda, P Coulter, D Cussans, C Damerell, E Devetak, J Fopma, B Foster, R Frost, R Gao, J Goldstein, T Greenshaw, K Harder, B Hawes, S Hillert, B Jeffery, JJ John, N Kundu, Y Li, P Murray, A Nomerotski, C Perry, K Stefanov, S Thomas, J Velthuis, T Wolliscroft, S Worm, J Yow, Z Zhang

The Linear Collider Flavour Identification (LCFI) Collaboration is developing the sensors, readout electronics and mechanical support structures for the vertex detector of the International Linear Collider (ILC). High speed readout is needed to ensure that the occupancy due to the pair production background at the ILC is kept below the 1% level. In order to satisfy this requirement, Column Parallel CCDs (CPCCDs), Column Parallel Readout chips (CPRs) and Column Parallel Driver chips (CPDs) have been developed. The CPCCD has to operate at a clock frequency of 50 MHz, which represents a difficult technical challenge due to the large sensor capacitance. The design and performance of the second generation CPCCD sensors, CPC2, and the new driver chip, CPD1, which meet these challenging requirements, are described. © 2010 Elsevier B.V. All rights reserved.

Pixel Imaging Mass Spectrometry with fast and intelligent Pixel detectors

Journal of Instrumentation 5 (2010)

A Nomerotski, M Brouard, E Campbell, A Clark, J Crooks, J Fopma, JJ John, AJ Johnsen, C Slater, R Turchetta, C Vallance, E Wilman, WH Yuen

We report on 'proof of concept' experiments in Pixel Imaging Mass Spectrometry (PImMS) using an ultra-fast frame-transfer CCD camera and also describe an intelligent CMOS sensor which is being developed for this application by the PImMS collaboration in the UK. PImMS is a combination of traditional TOF mass spectrometry and ion imaging. Information provided by the ion imaging gives access to valuable structural information of the molecule under investigation, in addition to the normal mass spectrum. Recording of the 2D spatial information of the arriving ions allows to reconstruct the ion velocity distributions for separate ion masses and to correlate them to each other. The new PImMS sensor will be capable of time stamping up to four arriving ions per pixel during the 200 μsec acquisition cycle with 100 nsec resolution which should meet the demanding requirements of complete recording of mass spectra of complex organic molecules. © 2010 IOP Publishing Ltd and SISSA.

The C-Band All-Sky Survey: Instrument design, status, and first-look data

Proceedings of SPIE - The International Society for Optical Engineering 7741 (2010)

OG King, C Copley, R Davies, R Davis, C Dickinson, YA Hafez, C Holler, JJ John, JL Jonas, ME Jones, JP Leahy, SJC Muchovej, TJ Pearson, ACS Readhead, MA Stevenson, AC Taylor

The C-Band All-Sky Survey (C-BASS) aims to produce sensitive, all-sky maps of diffuse Galactic emission at 5 GHz in total intensity and linear polarization. These maps will be used (with other surveys) to separate the several astrophysical components contributing to microwave emission, and in particular will allow an accurate map of synchrotron emission to be produced for the subtraction of foregrounds from measurements of the polarized Cosmic Microwave Background. We describe the design of the analog instrument, the optics of our 6.1 m dish at the Owens Valley Radio Observatory, the status of observations, and first-look data. © 2010 SPIE.

First results with prototype ISIS devices for ILC vertex detector

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 624 (2010) 465-469

C Damerell, Z Zhang, R Gao, J John John, Y Li, A Nomerotski, A Holland, G Seabroke, M Havranek, K Stefanov, A Kar-Roy, R Bell, D Burt, P Pool

The vertex detectors at the International Linear Collider (ILC) (there will be two of them, one for each of two general purpose detectors) will certainly be built with silicon pixel detectors, either monolithic or perhaps vertically integrated. However, beyond this general statement, there is a wide range of options supported by active R&D programmes all over the world. Pixel-based vertex detectors build on the experience at the SLAC large detector (SLD) operating at the SLAC linear collider (SLC), where a 307 Mpixel detector permitted the highest physics performance at LEP or SLC. For ILC, machine conditions demand much faster readout than at SLC, something like 20 time slices during the 1 ms bunch train. The approach of the image sensor with in-situ storage (ISIS) is unique in offering this capability while avoiding the undesirable requirement of 'pulsed power'. First results from a prototype device that approaches the pixel size of 20 μm square, needed for physics, are reported. The dimensional challenge is met by using a 0.18 μm imaging CMOS process, instead of a conventional CCD process. © 2010 Elsevier B.V. All rights reserved.

ISIS2: Pixel sensor with local charge storage for ILC vertex detector

International Linear Collider Workshop 2010, LCWS 2010 and ILC 2010 (2010)

Y Li, C Damerell, R Gao, R Gauld, JJ John, P Murray, A Nomerotski, K Stefanov, S Thomas, H Wilding, Z Zhang

ISIS (In-situ Storage Imaging Sensor) is a novel CMOS sensor with multiple charge storage capability developed for the ILC vertex detector by the Linear Collider Flavour Identification (LCFI) collaboration. This paper reports test results for ISIS2, the second generation of ISIS sensors implemented in a 0.18 micron CMOS process. The local charge storage and charge transfer were unambiguously demonstrated.