Cryogenic irradiation of an EMCCD for the WFIRST coronagraph: preliminary performance analysis

Bush, Nathan; Hall, D.; Holland, Andrew D.; Burgon, Ross; Murray, Neil J.; Gow, Jason; Jordan, D. M.; Demers, Richard; Harding, Leon K.; Nemati, Bijan; Hoenk, Michael E.; Michaels, Darren; Peddada, Pavani

doi:10.1117/12.2234628

Cited by 7 publications

(4 citation statements)

References 21 publications

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“…The trap pumping technique [13][14][15][16][17][18][19] allows the emission time constants of the intrinsic and radiation-induced defects within the silicon CCD to be calculated, which can then be collated to provide an overall representation of the spread of emission time constants within the device. The underlying theory is based upon Shockley-Read-Hall recombination statistics [9,10].…”

Section: Trap Pumpingmentioning

confidence: 99%

Effects of temperature anneal cycling on a cryogenically proton irradiated CCD

et al. 2021

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Throughout a typical Earth orbit a satellite is constantly bombarded by radiation with trapped and solar protons being of particular concern as they gradually damage the focal plane devices throughout the mission and degrade their performance. To understand the impact the damage has on CCDs and how it varies with their thermal history a proton radiation campaign has been carried out using a CCD280. The CCD is irradiated at 153 K and gradually warmed to 188 K in 5 K increments with Fe55 X-ray, dark current and trap pumping images taken at 153 K after each anneal step. The results show that despite the trap landscape changing throughout the anneal it has little impact on parallel charge transfer inefficiency. This is thought to be because most traps are unaffected and a lot of those that do anneal only move from the continuum between distinct trap species and into a nearby divacancy trap “peak” whose emission time constant is similar enough to still impact the CTI. In terms of using a CCD280 or similar devices in a mission the CTI being unaffected by thermal annealing up to 188 K means that any CTI correction needed as the radiation damage builds up does not have to take into account the thermal history of the focal plane. However, it is possible that a significant amount of annealing will occur at temperatures greater than 188 K and care should be taken when a mission is operating in this range to gather accurate pre-flight data.

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Section: Trap Pumpingmentioning

confidence: 99%

Effects of temperature anneal cycling on a cryogenically proton irradiated CCD

et al. 2021

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“…Investigations into the effect of proton irradiation on device characteristics have been completed on a number of EMCCDs [9] including testing for several missions such as the WFIRST mission [10]. Previous studies [5] have demonstrated that while these devices were still operational post proton Soldered to a PCB irradiation, increases in dark current, hot pixel density and CTI were observed.…”

Section: Proton Irradiation and Methodologymentioning

confidence: 99%

Ageing and proton irradiation damage of a low voltage EMCCD in a CMOS process

2018

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Electron Multiplying Charge Coupled Devices (EMCCDs) have revolutionised low light level imaging, providing highly sensitive detection capabilities. Implementing Electron Multiplication (EM) in Charge Coupled Devices (CCDs) can increase the Signal to Noise Ratio (SNR) and lead to further developments in low light level applications such as improvements in image contrast and single photon imaging. Demand has grown for EMCCD devices with properties traditionally restricted to Complementary Metal-Oxide-Semiconductor (CMOS) image sensors, such as lower power consumption and higher radiation tolerance. However, EMCCDs are known to experience an ageing effect, such that the gain gradually decreases with time. This paper presents results detailing EM ageing in an Electron Multiplying Complementary Metal-Oxide-Semiconductor (EMCMOS) device and its effect on several device characteristics such as Charge Transfer Inefficiency (CTI) and thermal dark signal. When operated at room temperature an average decrease in gain of over 20% after an operational period of 175 hours was detected. With many image sensors deployed in harsh radiation environments, the radiation hardness of the device following proton irradiation was also tested. This paper presents the results of a proton irradiation completed at the Paul Scherrer Institut (PSI) at a 10 MeV equivalent fluence of 4.15×10 10 protons/cm 2. The pre-irradiation characterisation, irradiation methodology and post-irradiation results are detailed, demonstrating an increase in dark current and a decrease in its activation energy. Finally, this paper presents a comparison of the damage caused by EM gain ageing and proton irradiation.

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“…Trap pumping has become an established technique over the last 10 years [11][12][13][14][15][16][17] and works on the premise that as each trap species has a specific range of emission time constants individual types can be identified within a CCD by using specialised clocking schemes. These schemes, rather than moving charge packets sequentially through the device pixel to pixel instead move the charge back and forth over the same pixels (known as pumping).…”

Section: Jinst 17 P10025mentioning

confidence: 99%

Improving radiation hardness in space-based Charge-Coupled Devices: an experimental validation of a new pre-fabrication modelling technique

Parsons¹,

Hall²,

Buggey³

et al. 2022

J. Inst.

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The soft X-ray imager (SXI) on the SMILE mission uses two large 4510x4510 back illuminated CCD370s to detect X-rays in the 0.2–2 keV range. These devices take heritage from the optical imaging PLATO mission CCD270s and have been optimised for low energy signals by including a parallel supplementary buried channel (SBC) which should reduce the volume of the charge cloud and thereby reduce the number of traps it interacts with as it is transferred through the CCD. The charge transfer performance improvement between the CCD270 and the CCD370 has been simulated using a combination of Silvaco and Matlab models to predict its characteristics pre-fabrication over a 102–105 electron signal range. Trap pumping measurements have been taken on both devices to count the number of traps present and hence calculate the mean amount of traps that exist per pixel across the range of signal levels. The trap pumping results are used to calculate a charge transfer performance improvement that shows good agreement with the simulated values, especially in the SXI science band. These results bring added confidence to the early performance modelling of the SMILE SXI instrument and is a good indicator that the simulations are accurate enough to be used to model devices with more advanced geometries such as an SBC and can be used in future CCD missions, where radiation-hardness and hence good charge transfer characteristics are key.

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Cryogenic irradiation of an EMCCD for the WFIRST coronagraph: preliminary performance analysis

Cited by 7 publications

References 21 publications

Effects of temperature anneal cycling on a cryogenically proton irradiated CCD

Effects of temperature anneal cycling on a cryogenically proton irradiated CCD

Ageing and proton irradiation damage of a low voltage EMCCD in a CMOS process

Improving radiation hardness in space-based Charge-Coupled Devices: an experimental validation of a new pre-fabrication modelling technique

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