@article{Zhao2017c,
	title = {Coincidence velocity map imaging using {Tpx3Cam}, a time stamping optical camera with 1.5 ns timing resolution},
	volume = {88},
	issn = {0034-6748},
	url = {http://aip.scitation.org/doi/10.1063/1.4996888},
	doi = {10.1063/1.4996888},
	number = {11},
	journal = {Review of Scientific Instruments},
	author = {Zhao, Arthur and van Beuzekom, Martin and Bouwens, Bram and Byelov, Dmitry and Chakaberia, Irakli and Cheng, Chuan and Maddox, Erik and Nomerotski, Andrei and Svihra, Peter and Visser, Jan and Vrba, Vaclav and Weinacht, Thomas},
	month = nov,
	year = {2017},
	keywords = {\#nosource},
	pages = {113104},
}

@article{Zhao2017,
	title = {Coincidence velocity map imaging using a single detector},
	volume = {147},
	issn = {0021-9606},
	url = {http://aip.scitation.org/doi/10.1063/1.4981917},
	doi = {10.1063/1.4981917},
	abstract = {We demonstrate a single-detector velocity map imaging setup which is capable of rapidly switching between coincidence and non-coincidence measurements. By rapidly switching the extraction volt-ages on the electrostatic lenses, both electrons and ions can be collected in coincidence with a single detector. Using a fast camera as the 2D detector avoids the saturation problem associated with tradi-tional delay line detectors and allows for easy transitions between coincidence and non-coincidence data collection modes. This is a major advantage in setting up a low-cost and versatile coincidence apparatus. We present both coincidence and non-coincidence measurements of strong field atomic and molecular ionization. Published by AIP Publishing. [http://dx.},
	number = {1},
	journal = {The Journal of Chemical Physics},
	author = {Zhao, Arthur and Sándor, Péter and Weinacht, Thomas},
	year = {2017},
	keywords = {\#nosource},
	pages = {013922},
}

We demonstrate a single-detector velocity map imaging setup which is capable of rapidly switching between coincidence and non-coincidence measurements. By rapidly switching the extraction volt-ages on the electrostatic lenses, both electrons and ions can be collected in coincidence with a single detector. Using a fast camera as the 2D detector avoids the saturation problem associated with tradi-tional delay line detectors and allows for easy transitions between coincidence and non-coincidence data collection modes. This is a major advantage in setting up a low-cost and versatile coincidence apparatus. We present both coincidence and non-coincidence measurements of strong field atomic and molecular ionization. Published by AIP Publishing. [http://dx.

@article{Furch2017a,
	title = {Ion-ion coincidence imaging at high event rate using an in-vacuum pixel detector},
	volume = {147},
	issn = {0021-9606},
	url = {http://aip.scitation.org/doi/10.1063/1.4981126},
	doi = {10.1063/1.4981126},
	abstract = {A new ion-ion coincidence imaging spectrometer based on a pixelated complementary metal-oxide-semiconductor detector has been developed for the investigation of molecular ionization and fragmentation processes in strong laser fields. Used as a part of a velocity map imaging spectrometer, the detection system is comprised of a set of microchannel plates and a Timepix detector. A fast time-to-digital converter (TDC) is used to enhance the ion time-of-flight resolution by correlating timestamps registered separately by the Timepix detector and the TDC. In addition, sub-pixel spatial resolution ({\textless}6 μm) is achieved by the use of a center-of-mass centroiding algorithm. This performance is achieved while retaining a high event rate (104 per s). The spectrometer was characterized and used in a proof-of-principle experiment on strong field dissociative double ionization of carbon dioxide molecules (CO2), using a 400 kHz repetition rate laser system. The experimental results demonstrate that the spectrometer can de...},
	number = {1},
	urldate = {2017-05-02},
	journal = {The Journal of Chemical Physics},
	author = {Furch, Federico J. and Durá, Judith and Tremsin, Anton S. and Vallerga, John and Schulz, Claus Peter and Rouzée, Arnaud and Vrakking, Marc J. J.},
	month = jul,
	year = {2017},
	note = {Publisher: AIP Publishing LLC},
	keywords = {carbon compounds, microchannel plates, molecule-photon collisions, photoionisation},
	pages = {013919},
}

A new ion-ion coincidence imaging spectrometer based on a pixelated complementary metal-oxide-semiconductor detector has been developed for the investigation of molecular ionization and fragmentation processes in strong laser fields. Used as a part of a velocity map imaging spectrometer, the detection system is comprised of a set of microchannel plates and a Timepix detector. A fast time-to-digital converter (TDC) is used to enhance the ion time-of-flight resolution by correlating timestamps registered separately by the Timepix detector and the TDC. In addition, sub-pixel spatial resolution (\textless6 μm) is achieved by the use of a center-of-mass centroiding algorithm. This performance is achieved while retaining a high event rate (104 per s). The spectrometer was characterized and used in a proof-of-principle experiment on strong field dissociative double ionization of carbon dioxide molecules (CO2), using a 400 kHz repetition rate laser system. The experimental results demonstrate that the spectrometer can de...

@article{Thompson2017,
	title = {Finite slice analysis ({FINA})—{A} general reconstruction method for velocity mapped and time-sliced ion imaging},
	volume = {147},
	issn = {0021-9606},
	url = {https://doi.org/10.1063/1.4979305},
	doi = {10.1063/1.4979305},
	number = {1},
	urldate = {2017-12-13},
	journal = {The Journal of Chemical Physics},
	author = {Thompson, J. O. F. and Amarasinghe, C. and Foley, C. D. and Suits, A. G.},
	month = jul,
	year = {2017},
	note = {Publisher: AIP Publishing LLC},
	keywords = {Monte Carlo methods, photodissociation, reaction kinetics theory},
	pages = {013913},
}

@article{Forbes2017,
	title = {Time-resolved multi-mass ion imaging: {Femtosecond} {UV}-{VUV} pump-probe spectroscopy with the {PImMS} camera},
	volume = {147},
	issn = {0021-9606},
	url = {http://arxiv.org/abs/1702.00744},
	doi = {10.1063/1.4978923},
	abstract = {The Pixel-Imaging Mass Spectrometry (PImMS) camera allows for 3D charged particle imaging measurements, in which the particle time-of-flight is recorded along with \$(x,y)\$ position. Coupling the PImMS camera to an ultrafast pump-probe velocity-map imaging spectroscopy apparatus therefore provides a route to time-resolved multi-mass ion imaging, with both high count rates and large dynamic range, thus allowing for rapid measurements of complex photofragmentation dynamics. Furthermore, the use of vacuum ultraviolet wavelengths for the probe pulse allows for an enhanced observation window for the study of excited state molecular dynamics in small polyatomic molecules having relatively high ionization potentials. Herein, preliminary time-resolved multi-mass imaging results from C\$\_2\$F\$\_3\$I photolysis are presented. The experiments utilized femtosecond UV and VUV (160.8{\textasciitilde}nm and 267{\textasciitilde}nm) pump and probe laser pulses in order to demonstrate and explore this new time-resolved experimental ion imaging configuration. The data indicates the depth and power of this measurement modality, with a range of photofragments readily observed, and many indications of complex underlying wavepacket dynamics on the excited state(s) prepared.},
	number = {1},
	journal = {The Journal of Chemical Physics},
	author = {Forbes, Ruaridh and Makhija, Varun and Veyrinas, Kévin and Stolow, Albert and Lee, Jason W. L. and Burt, Michael and Brouard, Mark and Vallance, Claire and Wilkinson, Iain and Lausten, Rune and Hockett, Paul},
	month = jul,
	year = {2017},
	note = {arXiv: 1702.00744},
	pages = {013911},
}

The Pixel-Imaging Mass Spectrometry (PImMS) camera allows for 3D charged particle imaging measurements, in which the particle time-of-flight is recorded along with $(x,y)$ position. Coupling the PImMS camera to an ultrafast pump-probe velocity-map imaging spectroscopy apparatus therefore provides a route to time-resolved multi-mass ion imaging, with both high count rates and large dynamic range, thus allowing for rapid measurements of complex photofragmentation dynamics. Furthermore, the use of vacuum ultraviolet wavelengths for the probe pulse allows for an enhanced observation window for the study of excited state molecular dynamics in small polyatomic molecules having relatively high ionization potentials. Herein, preliminary time-resolved multi-mass imaging results from C$_2$F$_3$I photolysis are presented. The experiments utilized femtosecond UV and VUV (160.8~nm and 267~nm) pump and probe laser pulses in order to demonstrate and explore this new time-resolved experimental ion imaging configuration. The data indicates the depth and power of this measurement modality, with a range of photofragments readily observed, and many indications of complex underlying wavepacket dynamics on the excited state(s) prepared.

@misc{Champenois2016,
	title = {{cpBasex}},
	url = {https://github.com/e-champenois/CPBASEX},
	publisher = {Github},
	author = {Champenois, Elio},
	year = {2016},
	keywords = {\#nosource},
}

@article{Slater2015,
	title = {Coulomb-explosion imaging using a pixel-imaging mass-spectrometry camera},
	volume = {91},
	issn = {1050-2947},
	url = {http://link.aps.org/doi/10.1103/PhysRevA.91.053424},
	doi = {10.1103/PhysRevA.91.053424},
	number = {5},
	journal = {Physical Review A},
	author = {Slater, Craig S. and Blake, Sophie and Brouard, Mark and Lauer, Alexandra and Vallance, Claire and Bohun, C. Sean and Christensen, Lauge and Nielsen, Jens H. and Johansson, Mikael P. and Stapelfeldt, Henrik},
	year = {2015},
	keywords = {\#nosource},
	pages = {1--14},
}

@article{Lee2014c,
	title = {Coincidence ion imaging with a fast frame camera},
	volume = {123303},
	issn = {0034-6748},
	doi = {10.1063/1.4903856},
	number = {May},
	journal = {Review of Scientific Instruments},
	author = {Lee, Suk Kyoung and Cudry, Fadia and Lin, Yun Fei and Lingenfelter, Steven and Winney, Alexander H. and Fan, Lin and Li, Wen},
	year = {2014},
	keywords = {\#nosource},
}

@article{Poikela2014,
	title = {Timepix3: a {65K} channel hybrid pixel readout chip with simultaneous {ToA}/{ToT} and sparse readout},
	volume = {9},
	issn = {1748-0221},
	url = {http://iopscience.iop.org/article/10.1088/1748-0221/9/05/C05013/meta},
	doi = {10.1088/1748-0221/9/05/C05013},
	abstract = {The Timepix3, hybrid pixel detector (HPD) readout chip, a successor to the Timepix [1] chip, can record time-of-arrival (ToA) and time-over-threshold (ToT) simultaneously in each pixel. ToA information is recorded in a 14-bit register at 40 MHz and can be refined by a further 4 bits with a nominal resolution of 1.5625 ns (640 MHz). ToT is recorded in a 10-bit over-flow controlled counter at 40 MHz. Pixels can be programmed to record 14 bits of integral ToT and 10 bits of event counting, both at 40 MHz. The chip is designed in 130 nm CMOS and contains 256 × 256 pixel channels (55 × 55 µm 2). The chip, which has more than 170 M transistors, has been conceived as a general-purpose readout chip for HPDs used in a wide range of applications. Com-mon requirements of these applications are operation without a trigger signal, and sparse readout where only pixels containing event information are read out. A new architecture has been designed for sparse readout and can achieve a throughput of up to 40 Mhits/s/cm 2 . The flexible architecture offers readout schemes ranging from serial (one link) readout (40 Mbps) to faster parallel (up to 8 links) readout of 5.12 Gbps. In the ToA/ToT operation mode, readout is simultaneous with data acquisition thus keeping pixels sensitive at all times. The pixel matrix is formed by super pixel (SP) structures of 2 × 4 pixels. This optimizes resources by sharing the pixel readout logic which transports data from SPs to End-of-Column (EoC) using a 2-phase handshake protocol. To reduce power consumption in applications with a low duty cycle, an on-chip power pulsing scheme has been implemented. The logic switches bias currents of the analog front-ends in a se-quential manner, and all front-ends can be switched in 800 ns. The digital design uses a mixture of commercial and custom standard cell libraries and was verified using Open Verification Methodol-ogy (OVM) and commercial timing analysis tools. The analog front-end and a voltage-controlled oscillator for 1.5625 ns timing resolution have been designed using full custom techniques.},
	number = {05},
	urldate = {2017-12-17},
	journal = {Journal of Instrumentation},
	author = {Poikela, T and Plosila, J and Westerlund, T and Campbell, M and Gaspari, M De and Llopart, X and Gromov, V and Kluit, R and Beuzekom, M van and Zappon, F and Zivkovic, V and Brezina, C and Desch, K and Fu, Y and Kruth, A},
	month = may,
	year = {2014},
	keywords = {CMOS readout of gaseous detectors, Front-end electronics for detec-tor readout, VLSI circuits},
	pages = {C05013--C05013},
}

The Timepix3, hybrid pixel detector (HPD) readout chip, a successor to the Timepix [1] chip, can record time-of-arrival (ToA) and time-over-threshold (ToT) simultaneously in each pixel. ToA information is recorded in a 14-bit register at 40 MHz and can be refined by a further 4 bits with a nominal resolution of 1.5625 ns (640 MHz). ToT is recorded in a 10-bit over-flow controlled counter at 40 MHz. Pixels can be programmed to record 14 bits of integral ToT and 10 bits of event counting, both at 40 MHz. The chip is designed in 130 nm CMOS and contains 256 × 256 pixel channels (55 × 55 µm 2). The chip, which has more than 170 M transistors, has been conceived as a general-purpose readout chip for HPDs used in a wide range of applications. Com-mon requirements of these applications are operation without a trigger signal, and sparse readout where only pixels containing event information are read out. A new architecture has been designed for sparse readout and can achieve a throughput of up to 40 Mhits/s/cm 2 . The flexible architecture offers readout schemes ranging from serial (one link) readout (40 Mbps) to faster parallel (up to 8 links) readout of 5.12 Gbps. In the ToA/ToT operation mode, readout is simultaneous with data acquisition thus keeping pixels sensitive at all times. The pixel matrix is formed by super pixel (SP) structures of 2 × 4 pixels. This optimizes resources by sharing the pixel readout logic which transports data from SPs to End-of-Column (EoC) using a 2-phase handshake protocol. To reduce power consumption in applications with a low duty cycle, an on-chip power pulsing scheme has been implemented. The logic switches bias currents of the analog front-ends in a se-quential manner, and all front-ends can be switched in 800 ns. The digital design uses a mixture of commercial and custom standard cell libraries and was verified using Open Verification Methodol-ogy (OVM) and commercial timing analysis tools. The analog front-end and a voltage-controlled oscillator for 1.5625 ns timing resolution have been designed using full custom techniques.

@article{Horio2013b,
	title = {Simultaneous generation of sub-20 fs deep and vacuum ultraviolet pulses in a single filamentation cell and application to time- resolved photoelectron imaging},
	volume = {21},
	doi = {10.1364/OE.21.022423},
	number = {19},
	journal = {Optics Express},
	author = {Horio, Takuya and Spesyvtsev, Roman and Suzuki, Toshinori},
	year = {2013},
	keywords = {\#nosource},
	pages = {22423--22428},
}

@article{Vallance2013,
	title = {Fast sensors for time-of-flight imaging applications.},
	volume = {16},
	issn = {1463-9084},
	url = {http://dx.doi.org/10.1039/c3cp53183j},
	doi = {10.1039/c3cp53183j},
	abstract = {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.},
	number = {2},
	urldate = {2014-01-10},
	journal = {Physical chemistry chemical physics : PCCP},
	author = {Vallance, Claire and Brouard, Mark and Lauer, Alexandra and Slater, Craig S and Halford, Edward and Winter, Benjamin and King, Simon J and Lee, Jason W L and Pooley, Daniel E and Sedgwick, Iain and Turchetta, Renato and Nomerotski, Andrei and John, Jaya John and Hill, Laura},
	month = dec,
	year = {2013},
	pmid = {24002354},
	keywords = {\#nosource, ★},
	pages = {383--95},
}

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.

@article{Lehmann2012,
	title = {Velocity map photoelectron-photoion coincidence imaging on a single detector.},
	volume = {83},
	issn = {1089-7623},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/23020358},
	doi = {10.1063/1.4749843},
	abstract = {Here we report on a new simplified setup for velocity map photoelectron-photoion coincidence imaging using only a single particle detector. We show that both photoelectrons and photoions can be extracted toward the same micro-channel-plate delay line detector by fast switching of the high voltages on the ion optics. This single detector setup retains essentially all the features of a standard two-detector coincidence imaging setup, viz., the high spatial resolution for electron and ion imaging, while only slightly decreasing the ion time-of-flight mass resolution. The new setup paves the way to a significant cost reduction in building a coincidence imaging setup for experiments aiming to obtain the complete correlated three-dimensional momentum distribution of electrons and ions.},
	number = {9},
	urldate = {2013-12-13},
	journal = {The Review of scientific instruments},
	author = {Lehmann, C Stefan and Ram, N Bhargava and Janssen, Maurice H M},
	month = sep,
	year = {2012},
	pmid = {23020358},
	keywords = {\#nosource},
	pages = {093103},
}

Here we report on a new simplified setup for velocity map photoelectron-photoion coincidence imaging using only a single particle detector. We show that both photoelectrons and photoions can be extracted toward the same micro-channel-plate delay line detector by fast switching of the high voltages on the ion optics. This single detector setup retains essentially all the features of a standard two-detector coincidence imaging setup, viz., the high spatial resolution for electron and ion imaging, while only slightly decreasing the ion time-of-flight mass resolution. The new setup paves the way to a significant cost reduction in building a coincidence imaging setup for experiments aiming to obtain the complete correlated three-dimensional momentum distribution of electrons and ions.

@phdthesis{Clarkin2012,
	title = {Chemical {Reaction} {Dynamics} at the {Statistical} {Ensemble} and {Molecular} {Frame} {Limits}},
	url = {http://hdl.handle.net/1974/7456},
	school = {Queen's University},
	author = {Clarkin, Owen J},
	year = {2012},
	note = {Issue: September},
	keywords = {\#nosource},
}

@article{Clark2012,
	title = {Multimass velocity-map imaging with the pixel imaging mass spectrometry ({PImMS}) sensor: {An} ultra-fast event-triggered camera for particle imaging},
	volume = {116},
	issn = {10895639},
	doi = {10.1021/jp309860t},
	abstract = {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.},
	number = {45},
	journal = {Journal of Physical Chemistry A},
	author = {Clark, Andrew T. and Crooks, Jamie P. and Sedgwick, Iain and Turchetta, Renato and Lee, Jason W L and John, Jaya John and Wilman, Edward S. and Hill, Laura and Halford, Edward and Slater, Craig S. and Winter, Benjamin and Yuen, Wei Hao and Gardiner, Sara H. and Lipciuc, M. Laura and Brouard, Mark and Nomerotski, Andrei and Vallance, Claire},
	year = {2012},
	pmid = {23102270},
	note = {ISBN: 1089-5639},
	keywords = {\#nosource},
	pages = {10897--10903},
}

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.

@article{John2012,
	title = {{PImMS}, a fast event-triggered monolithic pixel detector with storage of multiple timestamps},
	volume = {7},
	issn = {1748-0221},
	url = {http://stacks.iop.org/1748-0221/7/i=08/a=C08001},
	doi = {10.1088/1748-0221/7/08/C08001},
	abstract = {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.},
	number = {08},
	urldate = {2013-06-04},
	journal = {Journal of Instrumentation},
	author = {John, J J and Brouard, M and Clark, A and Crooks, J and Halford, E and Hill, L and Lee, J W L and Nomerotski, A and Pisarczyk, R and Sedgwick, I and Slater, C S and Turchetta, R and Vallance, C and Wilman, E and Winter, B and Yuen, W H},
	month = aug,
	year = {2012},
	pages = {C08001--C08001},
}

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.

@article{Liu2011,
	title = {He {I} ultraviolet photoelectron spectroscopy of benzene and pyridine in supersonic molecular beams using photoelectron imaging.},
	volume = {115},
	issn = {1520-5215},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/21413769},
	doi = {10.1021/jp1098574},
	abstract = {We performed He I ultraviolet photoelectron spectroscopy (UPS) of jet-cooled aromatic molecules using a newly developed photoelectron imaging (PEI) spectrometer. The PEI spectrometer can measure photoelectron spectra and photoelectron angular distributions at a considerably higher efficiency than a conventional spectrometer that uses a hemispherical energy analyzer. One technical problem with PEI is its relatively high susceptibility to background electrons generated by scattered He I radiation. To reduce this problem, we designed a new electrostatic lens that intercepts background photoelectrons emitted from the repeller plate toward the imaging detector. An energy resolution (ΔE/E) of 0.735\% at E = 5.461 eV is demonstrated with He I radiation. The energy resolution is limited by the size of the ionization region. Trajectory calculations indicate that the system is capable of achieving an energy resolution of 0.04\% with a laser if the imaging resolution is not limited. Experimental results are presented for jet-cooled benzene and pyridine, and they are compared with results in the literature.},
	number = {14},
	urldate = {2012-11-10},
	journal = {The Journal of Physical Chemistry A},
	author = {Liu, Suet-Yi and Alnama, Koutayba and Matsumoto, Jun and Nishizawa, Kiyoshi and Kohguchi, Hiroshi and Lee, Yuan-Pern and Suzuki, Toshinori},
	month = apr,
	year = {2011},
	pmid = {21413769},
	keywords = {\#nosource, Benzene, Benzene: chemistry, Free Radicals, Free Radicals: chemistry, Photoelectron Spectroscopy, Photoelectron Spectroscopy: instrumentation, Pyridines, Pyridines: chemistry, Spectrophotometry, Ultraviolet, Spectrophotometry, Ultraviolet: instrumentation, Ultraviolet, Ultraviolet: instrumentation},
	pages = {2953--65},
}

We performed He I ultraviolet photoelectron spectroscopy (UPS) of jet-cooled aromatic molecules using a newly developed photoelectron imaging (PEI) spectrometer. The PEI spectrometer can measure photoelectron spectra and photoelectron angular distributions at a considerably higher efficiency than a conventional spectrometer that uses a hemispherical energy analyzer. One technical problem with PEI is its relatively high susceptibility to background electrons generated by scattered He I radiation. To reduce this problem, we designed a new electrostatic lens that intercepts background photoelectrons emitted from the repeller plate toward the imaging detector. An energy resolution (ΔE/E) of 0.735% at E = 5.461 eV is demonstrated with He I radiation. The energy resolution is limited by the size of the ionization region. Trajectory calculations indicate that the system is capable of achieving an energy resolution of 0.04% with a laser if the imaging resolution is not limited. Experimental results are presented for jet-cooled benzene and pyridine, and they are compared with results in the literature.

@article{Chichinin2009,
	title = {Imaging chemical reactions - {3D} velocity mapping},
	volume = {28},
	issn = {0144-235X},
	url = {http://www.tandfonline.com/doi/abs/10.1080/01442350903235045},
	doi = {10.1080/01442350903235045},
	number = {4},
	urldate = {2012-07-16},
	journal = {International Reviews in Physical Chemistry},
	author = {Chichinin, A. I. and Gericke, K.-H. and Kauczok, S. and Maul, C.},
	month = oct,
	year = {2009},
	keywords = {\#nosource, ion imaging, reaction dynamics, rempi, velocity map imaging},
	pages = {607--680},
}

@article{Kauczok2009,
	title = {Three-dimensional velocity map imaging: setup and resolution improvement compared to three-dimensional ion imaging.},
	volume = {80},
	issn = {1089-7623},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/19725645},
	doi = {10.1063/1.3186734},
	abstract = {For many years the three-dimensional (3D) ion imaging technique has not benefited from the introduction of ion optics into the field of imaging in molecular dynamics. Thus, a lower resolution of kinetic energy as in comparable techniques making use of inhomogeneous electric fields was inevitable. This was basically due to the fact that a homogeneous electric field was needed in order to obtain the velocity component in the direction of the time of flight spectrometer axis. In our approach we superimpose an Einzel lens field with the homogeneous field. We use a simulation based technique to account for the distortion of the ion cloud caused by the inhomogeneous field. In order to demonstrate the gain in kinetic energy resolution compared to conventional 3D Ion Imaging, we use the spatial distribution of H(+) ions emerging from the photodissociation of HCl following the two photon excitation to the V (1)Sigma(+) state. So far a figure of merit of approximately four has been achieved, which means in absolute numbers Delta v/v = 0.022 compared to 0.086 at v approximately = 17,000 m/s. However, this is not a theoretical limit of the technique, but due to our rather short TOF spectrometer (15 cm). The photodissociation of HBr near 243 nm has been used to recognize and eliminate systematic deviations between the simulation and the experimentally observed distribution. The technique has also proven to be essential for the precise measurement of translationally cold distributions.},
	number = {8},
	urldate = {2012-07-23},
	journal = {The Review of scientific instruments},
	author = {Kauczok, S and Gödecke, N and Chichinin, a I and Veckenstedt, M and Maul, C and Gericke, K-H},
	month = aug,
	year = {2009},
	pmid = {19725645},
	keywords = {\#nosource},
	pages = {083301},
}

For many years the three-dimensional (3D) ion imaging technique has not benefited from the introduction of ion optics into the field of imaging in molecular dynamics. Thus, a lower resolution of kinetic energy as in comparable techniques making use of inhomogeneous electric fields was inevitable. This was basically due to the fact that a homogeneous electric field was needed in order to obtain the velocity component in the direction of the time of flight spectrometer axis. In our approach we superimpose an Einzel lens field with the homogeneous field. We use a simulation based technique to account for the distortion of the ion cloud caused by the inhomogeneous field. In order to demonstrate the gain in kinetic energy resolution compared to conventional 3D Ion Imaging, we use the spatial distribution of H(+) ions emerging from the photodissociation of HCl following the two photon excitation to the V (1)Sigma(+) state. So far a figure of merit of approximately four has been achieved, which means in absolute numbers Delta v/v = 0.022 compared to 0.086 at v approximately = 17,000 m/s. However, this is not a theoretical limit of the technique, but due to our rather short TOF spectrometer (15 cm). The photodissociation of HBr near 243 nm has been used to recognize and eliminate systematic deviations between the simulation and the experimentally observed distribution. The technique has also proven to be essential for the precise measurement of translationally cold distributions.

@article{Vredenborg2008,
	title = {A photoelectron-photoion coincidence imaging apparatus for femtosecond time-resolved molecular dynamics with electron time-of-flight resolution of sigma=18 ps and energy resolution {Delta} {E}/{E}=3.5\%.},
	volume = {79},
	issn = {0034-6748},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/18601398},
	doi = {10.1063/1.2949142},
	abstract = {We report on the construction and performance of a novel photoelectron-photoion coincidence machine in our laboratory in Amsterdam to measure the full three-dimensional momentum distribution of correlated electrons and ions in femtosecond time-resolved molecular beam experiments. We implemented sets of open electron and ion lenses to time stretch and velocity map the charged particles. Time switched voltages are operated on the particle lenses to enable optimal electric field strengths for velocity map focusing conditions of electrons and ions separately. The position and time sensitive detectors employ microchannel plates (MCPs) in front of delay line detectors. A special effort was made to obtain the time-of-flight (TOF) of the electrons at high temporal resolution using small pore (5 microm) MCPs and implementing fast timing electronics. We measured the TOF distribution of the electrons under our typical coincidence field strengths with a temporal resolution down to sigma=18 ps. We observed that our electron coincidence detector has a timing resolution better than sigma=16 ps, which is mainly determined by the residual transit time spread of the MCPs. The typical electron energy resolution appears to be nearly laser bandwidth limited with a relative resolution of DeltaE(FWHM)/E=3.5\% for electrons with kinetic energy near 2 eV. The mass resolution of the ion detector for ions measured in coincidence with electrons is about Deltam(FWHM)/m=14150. The velocity map focusing of our extended source volume of particles, due to the overlap of the molecular beam with the laser beams, results in a parent ion spot on our detector focused down to sigma=115 microm.},
	number = {6},
	urldate = {2012-07-17},
	journal = {The Review of scientific instruments},
	author = {Vredenborg, Arno and Roeterdink, Wim G and Janssen, Maurice H M},
	month = jun,
	year = {2008},
	pmid = {18601398},
	keywords = {\#nosource},
	pages = {063108},
}

We report on the construction and performance of a novel photoelectron-photoion coincidence machine in our laboratory in Amsterdam to measure the full three-dimensional momentum distribution of correlated electrons and ions in femtosecond time-resolved molecular beam experiments. We implemented sets of open electron and ion lenses to time stretch and velocity map the charged particles. Time switched voltages are operated on the particle lenses to enable optimal electric field strengths for velocity map focusing conditions of electrons and ions separately. The position and time sensitive detectors employ microchannel plates (MCPs) in front of delay line detectors. A special effort was made to obtain the time-of-flight (TOF) of the electrons at high temporal resolution using small pore (5 microm) MCPs and implementing fast timing electronics. We measured the TOF distribution of the electrons under our typical coincidence field strengths with a temporal resolution down to sigma=18 ps. We observed that our electron coincidence detector has a timing resolution better than sigma=16 ps, which is mainly determined by the residual transit time spread of the MCPs. The typical electron energy resolution appears to be nearly laser bandwidth limited with a relative resolution of DeltaE(FWHM)/E=3.5% for electrons with kinetic energy near 2 eV. The mass resolution of the ion detector for ions measured in coincidence with electrons is about Deltam(FWHM)/m=14150. The velocity map focusing of our extended source volume of particles, due to the overlap of the molecular beam with the laser beams, results in a parent ion spot on our detector focused down to sigma=115 microm.

@article{Rolles,
	title = {A velocity map imaging spectrometer for electron–ion and ion–ion coincidence experiments with synchrotron radiation},
	volume = {261},
	issn = {0168583X},
	url = {http://linkinghub.elsevier.com/retrieve/pii/S0168583X07009949},
	doi = {10.1016/j.nimb.2007.04.186},
	number = {1-2},
	journal = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms},
	author = {Rolles, D and Pešić, Z.D. and Perri, M and Bilodeau, R.C. and Ackerman, G.D. and Rude, B.S. and Kilcoyne, A.L.D. and Bozek, J.D. and Berrah, N.},
	month = aug,
	year = {2007},
	keywords = {\#nosource, coincidence, fragmentation, imaging, photoionization, velocity map},
	pages = {170--174},
}

@article{Ashfold2006a,
	title = {Imaging the dynamics of gas phase reactions.},
	volume = {8},
	issn = {1463-9076},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/16482242},
	doi = {10.1039/b509304j},
	abstract = {Ion imaging methods are making ever greater impact on studies of gas phase molecular reaction dynamics. This article traces the evolution of the technique, highlights some of the more important breakthroughs with regards to improving image resolution and in image processing and analysis methods, and then proceeds to illustrate some of the many applications to which the technique is now being applied--most notably in studies of molecular photodissociation and of bimolecular reaction dynamics.},
	number = {1},
	urldate = {2012-07-17},
	journal = {Physical chemistry chemical physics : PCCP},
	author = {Ashfold, Michael N R and Nahler, N Hendrik and Orr-Ewing, Andrew J and Vieuxmaire, Olivier P J and Toomes, Rachel L and Kitsopoulos, Theofanis N and Garcia, Ivan Anton and Chestakov, Dmitri a and Wu, Shiou-Min and Parker, David H},
	month = jan,
	year = {2006},
	pmid = {16482242},
	keywords = {\#nosource, Gases, Gases: chemistry, Image Processing, Computer-Assisted, Image Processing, Computer-Assisted: instrumentati, Image Processing, Computer-Assisted: methods, Image Processing, Computer-Assisted: trends, Kinetics, Phase Transition, Photolysis, Thermodynamics, ★},
	pages = {26--53},
}

Ion imaging methods are making ever greater impact on studies of gas phase molecular reaction dynamics. This article traces the evolution of the technique, highlights some of the more important breakthroughs with regards to improving image resolution and in image processing and analysis methods, and then proceeds to illustrate some of the many applications to which the technique is now being applied–most notably in studies of molecular photodissociation and of bimolecular reaction dynamics.

@article{Suzuki2006,
	title = {Femtosecond time-resolved photoelectron imaging.},
	volume = {57},
	issn = {0066-426X},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/16599821},
	doi = {10.1146/annurev.physchem.57.032905.104601},
	abstract = {Femtosecond time-resolved photoelectron imaging (TRPEI) is a variant of time-resolved photoelectron spectroscopy used in the study of gas-phase photoinduced dynamics. A new observable, time-dependent photoionization-differential cross section provides useful information on wave-packet motions, electronic dephasing, and photoionization dynamics. This review describes fundamental issues and the most recent works involving TRPEI.},
	urldate = {2012-07-17},
	journal = {Annual review of physical chemistry},
	author = {Suzuki, Toshinori},
	month = jan,
	year = {2006},
	pmid = {16599821},
	keywords = {\#nosource, abstract femtosecond time-resolved photoelectron, imaging, is a variant, of gas-phase photoin-, of time-resolved photoelectron spectroscopy, photoelectron-angular distribution, photoionization-differential cross sections, trpei, ultrafast spectroscopy, used in the study, wave-packet dynamics},
	pages = {555--92},
}

Femtosecond time-resolved photoelectron imaging (TRPEI) is a variant of time-resolved photoelectron spectroscopy used in the study of gas-phase photoinduced dynamics. A new observable, time-dependent photoionization-differential cross section provides useful information on wave-packet motions, electronic dephasing, and photoionization dynamics. This review describes fundamental issues and the most recent works involving TRPEI.

@article{Garcia2004,
	title = {Two-dimensional charged particle image inversion using a polar basis function expansion},
	volume = {75},
	issn = {0034-6748},
	url = {http://scitation.aip.org/content/aip/journal/rsi/75/11/10.1063/1.1807578},
	doi = {10.1063/1.1807578},
	number = {11},
	urldate = {2014-10-08},
	journal = {Review of Scientific Instruments},
	author = {Garcia, Gustavo a. and Nahon, Laurent and Powis, Ivan},
	month = nov,
	year = {2004},
	pages = {4989--4996},
}

@book{Whitaker2003,
	title = {Imaging in {Molecular} {Dynamics} {Technology} and {Applications}},
	isbn = {0-521-81059-0},
	url = {http://www.cambridge.org/us/academic/subjects/chemistry/physical-chemistry/imaging-molecular-dynamics-technology-and-applications},
	publisher = {Cambridge University Press},
	editor = {Whitaker, Benjamin J.},
	year = {2003},
	keywords = {\#nosource},
}

@article{Parker1997a,
	title = {Photoelectron and photofragment velocity map imaging of state-selected molecular oxygen dissociation/ionization dynamics},
	volume = {107},
	issn = {00219606},
	url = {http://link.aip.org/link/JCPSA6/v107/i7/p2357/s1&Agg=doi},
	doi = {10.1063/1.474624},
	number = {7},
	journal = {The Journal of Chemical Physics},
	author = {Parker, D. H. and Eppink, A. T. J. B.},
	year = {1997},
	keywords = {\#nosource},
	pages = {2357},
}

@article{Parker1997,
	title = {Velocity map imaging of ions and electrons using electrostatic lenses: {Application} in photoelectron and photofragment ion imaging of molecular oxygen},
	volume = {68},
	issn = {00346748},
	url = {http://scitation.aip.org/content/aip/journal/rsi/68/9/10.1063/1.1148310},
	doi = {10.1063/1.1148310},
	number = {9},
	urldate = {2014-07-24},
	journal = {Review of Scientific Instruments},
	author = {Eppink, Andre T. J. B. and Parker, David H},
	year = {1997},
	keywords = {\#nosource},
	pages = {3477},
}

@article{Wood1982b,
	title = {Computerized refractive index measurements for bulk materials at {UV}, visible, and {IR} wavelengths},
	volume = {53},
	issn = {0034-6748},
	url = {http://aip.scitation.org/doi/10.1063/1.1136814},
	doi = {10.1063/1.1136814},
	number = {1},
	journal = {Review of Scientific Instruments},
	author = {Wood, D L and Fleming, J W},
	month = jan,
	year = {1982},
	keywords = {\#nosource},
	pages = {43--47},
}

@misc{noauthor_pimms_nodate,
	title = {{PImMS} - {Home}},
	url = {http://pimms.chem.ox.ac.uk/index.php},
	urldate = {2014-03-02},
	keywords = {\#nosource, CMOS, PImMS, PImMS camera, PImMS sensor, fast camera, fast-camera, time stamping, time-stamping},
}