Purchasing a Back-illuminated
sCMOS for Astronomy &Physical Sciences?
Seven Reasons To Choose Marana
Author: Dr Colin Coates

andor.oxinst.com
1Technical Note
Considering a Back-illuminated sCMOS for Astronomy and Physical Sciences:

7 Reasons to Choose Andor Marana
Introduction

The Marana sCMOS camera platform has been designed to deliver
the ultimate in performance, longevity and experimental adaptability,
pushing the absolute best out of high-end sCMOS sensors. Marana has
also been designed with the solution needs of Astronomers, Physicists
and Chemists firmly in mind, offering features and functionality that are
particularly relevant within these fields.
Back-illuminated sCMOS sensors are growing in popularity, primarily due
to the best-in-class Quantum Efficiency (QE) performance that they offer.
It therefore makes sense to combine these high-end sensors with
best-in-class performance across all other key parameters. For those
who have made the decision to purchase a back-illuminated sCMOS
camera, here we offer seven key reasons that the Andor Marana should
be your back-illuminated sCMOS of choice for Astronomy and Physical Sciences applications.
Marana is currently available in two models:Model Option

Array

Pixel Size

Frame Rate (16-bit)

Description

Marana 4.2B-11

2048 x 2048

11 µm

24

Superior Field of View

Marana 4.2B-6

2048 x 2048

6.5 µm74

Fastest Speed

1. The Most Sensitive Back-illuminated sCMOS Available
Both back-illuminated Marana models feature 95%
Quantum Efficiency (QE) with market-leading vacuum
cooling to -45 °C. Benefiting from a unique vacuum design,
Marana thermoelectrically cools to -25 °C using only theinternal fan for heat dissipation, pushing down to a hugely
competitive -45 °C utilizing liquid assisted cooling. The
darkcurrent of the back-illuminated sCMOS sensors is asignificant contributor to overall system noise, so effective
cooling becomes essential. For example, with air cooling,
Marana 4.2B-11 has almost 5x lower darkcurrent than thenearest physical science competing camera that utilizes the

Figure 1: Air (fan) cooled and Liquid cooled performance of Marana 4.2B-11, versus the nearest competitive back-illuminated sCMOS camera forphysical sciences.

Marana 4.2B-6 Low Noise mode: Furthermore, the Marana 4.2B-6 model offers a specific ‘Low Noisemode’, that further reduces readout noise from 1.6 e- down to only 1.2 e- (typical). The primary trade-offof this mode is pixel well depth, reducing down to 1800 e-. Maximum frame rate, while still fast for many
applications, also reduces from 74 fps down to 44 fps in Low Noise mode. However, the mode is ideal
when highest possible sensitivity is a priority, for example when performing fluorescence Quantum Gas
measurements of low atom numbers.
Having the most sensitive Back-illuminated sCMOS camera carries a host of practical advantages within
Astronomy and Physical Sciences, for example:
P Detect smaller objects - more successful Space Debris and NEO tracking
P Lower laser powers/doses - preserve photosensitive samples
P Lower detection limits - detect and quantify trace concentrations, e.g. spectroscopy
P Lower exposure times - follow faster events with high SNR, e.g. Pulsars and fast BEC dynamics
P Narrowband filters – such as use of ultra-narrowband Solar imaging of specific emission lines
P Detect fluorescence from discrete atoms - more successful Quantum Gas/BEC experiments
Back-illuminated sensors are valued specifically for their enhanced sensitivity. It makes sense to choose
the most sensitive camera adaption of this high-end technology.

2. Largest Field of View Available: Marana 4.2B-11
Marana 4.2B-11 offers the largest field of view solution, combined with a long exposure capability,
compared with competitive cameras that also use the same back-illuminated sensor type from
GPixel. The GSENSE400BSI sensor of Marana has an impressive 32 mm diagonal. However, camera
companies to date have not been able to utilize it without severe restrictions, the reason being that thenative operation of the sensor exhibits edge glow! The approach so far has either been to (a) live withthe full unsuppressed glow; (b) only use the middle of the sensor; or (c) firmware restrict exposure times
to much less than 100 ms in order to contain the impact of glow on experiments. Marana 4.2B-11
features a unique real time approach to suppress the effects of glow and unlock the full sensor array,presenting an exclusive solution for capturing a large field of view across a wider range of exposure
conditions.

Figure 2: Scale representation of Field of View difference
between Marana 4.2B-11 and a competitor physical sciencecamera utilizing the same GSENSE400BSI back-illuminated
sCMOS sensor, restricted to 1200 x 1200 max. resolution.

Marana 7 Reasons
The Marana 4.2B-11 is native F-mount andcan be compared against “Competitor A”
above, a camera using the same sensor but
cropped down to 1200 x 1200 pixel format.
By cropping the sensor down, this camera
can avoid sensor glow issues that affect theedges of this sensor. However, Marana 4.2B11 enables the full native 2048 x 2048 of thearray to be harnessed. Figure 2 shows the
191% larger field of view advantage offered by
Marana 4.2B-11.
Furthermore, the Marana 4.2-11 allows useof the full 2048 x 2048 array with exposures
up to several seconds. This is significantly enabling, as the nearest competing physical science camera
platform that has opened the full sensor array has addressed the sensor glow effect through imposing asevere restriction on the maximum exposure time, limiting to only 30 milliseconds.
Maximizing field of view with Back-illuminated sCMOS cameras is highly beneficial for a range of physicalscience applications, for example:
P Space Debris and NEO tracking – detect and track objects across greater area of sky
P Solar Astronomy – image sun spots and solar flares, maintaining structural detail
P Tomography – 3D reconstruct larger objects without sacrificing resolution
P Wafer inspection - detect greater wafer area with high resolution
P Hyperspectral imaging - Extended high density multi-fiber input, or push broom hyperspectral overwide spatial and spectral ranges.

Figure 3: Dark exposure (1 sec), using a 1024 x 2048 region of the GSENSE400 BSI sensor. Images are compared:
left - without, and right - with the Anti-Glow Technology of Marana 4.2B-11, employing the exact same intensity scaling.

3. Superior Quality & Longevity – UltraVacTM
Why Vacuum Technology? As well as affording superior minimization of the noise floor, the performance
longevity benefits of Andor’s vacuum sensor enclosure are considerable.
REASON 1: Sensor Protection - Unless protected, back-illuminated silicon sensors are susceptible
to attack from moisture, hydrocarbons and other gas contaminants, resulting in gradual performance
decline, including QE decline. UltravacTM, Andor’s proprietary approach to vacuum enclosures, withminimized out-gassing, offers the ultimate level of sensor protection.
REASON 2: No re-backfilling of sensor enclosure required - Cameras that do not use vacuum
enclosures instead use a method called back-filling, whereby the sensor enclosure contains a positive
pressure of dry gas, separated from the external atmosphere by only O-ring seals. Over time,moisture and gas from the atmosphere will ingress into the sensor enclosure and compromise thesystem, resulting in loss of cooling capability and often moisture appearing on the sensor. The cameras
then have to be sent back to the factory for repair, re-backfilling and
ULTRAVactm Technology
resealing, often outside of the warranty period. The UltraVacTM uses ahermetic vacuum seal, completely preventing any gas ingress from theoutside environment. The vast majority of cameras hold their cooling
Hermetic seal
performance indefinitely.
Marana is the ONLY physical sciences back-illuminated sCMOS
camera on the market that benefits from a vacuum sensor enclosure.
Vacuum sensor technology is one of Andor’s core technology
strengths, and we have a fantastic track record of vacuum integrity andassociated camera longevity, stretching back more than 25 years.

VacuumSensorFigure 4: Andor’s UltraVacTM provides superior sensor protection and performance longevity.

Low Maintenance Astronomy: The vacuum-protected longevity benefits of Marana are particularly
relevant to the needs of astronomers, where cameras are often in remote unmanned observing
locations and need to operate without service intervention, over long durations of time. Furthermore,
observing time is often tightly scheduled and we need to know the camera is not going to suffer froma cooling compromise or moisture build up, either on the sensor or on the outside of the window. Allof this ultimately translates not only into a higher experimental throughout, but also into a lower cost ofownership.

4. Extended Dynamic Range & Higher Quantitative Accuracy
Marana 4.2B-11 and Marana 4.2B-6 each offer Extended Dynamic Range functionality, supported
by a 16-bit data range. Harnessing an innovative ‘dual amplifier’ sensor architecture, we can accessthe maximum pixel well depth AND the lowest noise simultaneously, ensuring that we can quantify
extremely weak and relatively bright signal regions in one exposure. This functionality is useful for
accurately visualizing and quantifying many challenging scenes that have both weak and bright regions,such as Space Debris, NEOs, Solar signals and spectroscopic materials characterisations.

Trad

Marana 7 Reasons
Figure 5: Measurements taken of a highdynamic range test chart using Marana
4.2B-11 in Extended Dynamic Range Mode,
which enables accurate quantification of
signal intensities that range from the noise
floor detection limit to the full pixel welldepth.

Market Leading Linearity: To achieve best in class quantification accuracy, Andor have implemented
enhanced real time on- head intelligence to deliver linearity of > 99.7%.
Many applications in physical sciences require accurate quantitative information rather than simply
structural detail, for example Astro-Photometry, Solar measurements and quantitative Spectroscopic
characterisations.
Further Extending Dynamic Range through Fast Image Stacking: The fast, low noise readout of MaranasCMOS is ideal for massively extending dynamic range through rapid stacking (accumulation) of multiple
frames. For example, the plot below shows Dynamic Range and Effective Well Depth as a functionof the number of stacked (accumulated) frames, plotted for Marana 4.2B-6. A Dynamic Range of
188,280:1, and a corresponding Effective Well Depth of 1,650,000 electrons can be reached with only
30 stacked frames. At maximum frame rate, this number of accumulated frames takes only 0.4 secs
to acquire, achieving > 2 fps. This capability is significant for a range of challenges across imaging andspectroscopic characterisations.

Figure 6: Dynamic Range and Effective Well Depth as a function of the number of stacked (accumulated) frames, plotted for Marana 4.2B-6.

5. Faster Frame Rates
Marana models offer fast frame rate capability, rendering them ideal for dynamic applications while
avoiding motion smear, benefiting applications such as Space debris and NEO tracking, Pulsar
imaging, Solar flares, Sunspot flashes/waves, Lucky imaging/Speckle Interferometry, AO wavefront
sensing and Quantum Gases/BEC dynamics. Region of Interest (ROI) can be utilized to considerably
boost frame rates further.
Marana 4.2B-6 offers absolute fastest speeds, combined with high dynamic range: Marana 4.2B6 is the best model for achieving fast speeds under all imaging conditions. It offers up to 74 fps (fullresolution array) without a sacrifice in dynamic range, i.e. in ‘Fast High Dynamic Range mode’. Marana
4.2B is 72% faster than its nearest competitor (see below table)!
Max Frame Rate (16-bit)
ROI Size

Marana 4.2B-6

Competitor A

2048 x 2048

74 fps

43 fps2048 x 1024

147 fps

87 fpsTable 1: Not all commercial cameras utilizing the GS2020BSI sensor achieve such fast frame rates. Maximum frame rates of Marana 4.2B-6 are shown here
versus a competitive camera using the same sensor that does not offer such fast speeds.

Marana 4.2B-11 12-bit mode for 2x speed boost: Marana 4.2B-11 is architected to offer both ‘High
Dynamic Range (16-bit) mode’ and ‘Fast Speed (12-bit) mode’. The latter is selected specifically toaccelerate frame rate of this model by 2x, for any ROI size, while sacrificing some dynamic range. The
mode is useful for imaging fast phenomena that are exclusively low light, such as following dynamics on
discrete numbers of fluorescent ultra-cold atoms.
Max Frame Rate (12-bit)
ROI Size

Marana 4.2B-11

Competitor B

2048 x 2048

48 fps

24 fps1608 x 1608

60.5 fps

30 fpsTable 2: Not all commercial cameras utilizing the GS400BSI sensor offer this boosted speed capability. Maximum frame rates of Marana 4.2B-11 are shown
here versus a competitive camera using the same sensor that does not offer this 12-bit fast speed mode.

Marana 7 Reasons
6. Enhanced Flexibility: Adapt to a Wide Range of Experimental Needs
The Marana platform has been designed to meet the needs and challenges of modern research, which often
requires that the camera has inherent feature flexibility and experimental modes, to be adapted across multiple
set-ups and experimental configurations. The following areas of flexibility are inherent to the Marana platform:

P Air and Liquid Cooling – Not only can the Marana be used in liquid cooled operation to maximize sensitivity
in extreme low light conditions, use of liquid cooling rather than fan assisted cooling can also be beneficial in
optical configurations that are particularly vibration sensitive.

P Flexible Readout Modes
Marana 4.2B-6: The ‘Fast High Dynamic Range (16-bit) mode’ of Marana 4.2B-6 achieves maximum dynamic
range of 34,000:1 while simultaneously achieving maximum frame rate of 74 fps. The ‘Low Noise (12-bit)mode’ of Marana 4.2B-6, described in Section 1, is used for achieving absolute maximum sensitivity under
reduced dynamic range conditions.
Marana 4.2B-11: The ‘High Dynamic Range (16-bit) mode’ of Marana 4.2B-11 is the Extended Dynamic
Range mode, ideal for imaging samples that have both weak and bright signal regions. The ‘Fast Speed (12bit) mode’ of Marana 4.2B-11, described in Section 5, can be utilized to double the available frame rate fromany selected ROI size, superb for adapting to low light experiments that require excellent temporal resolution,such as Adaptive Optics wavefront sensing.

P Flexible Pixel Binning – The Marana models feature on-camera flexible pixel binning, user definable to 1 pixel
granularity. Greater binning flexibility can be useful for some photon starved applications where resolution canbe sacrificed in favour of enhanced photon collection area per pixel - e.g. extremely low light luminescence
experiments.

P Multiple Optical Mount Options - Marana 4.2B-11 ships as default with standard F-mount optical
coupling, however, the user can readily convert the camera for use with C-mount lenses, simply by selecting
this additional optical mount accessories when ordering (or order separately at a later time if preferred).
C-mount may be used with cropped sub-array sizes up to 1400 x 1400, yielding a 22mm sensor diagonal.
The F-mount may also be readily detached to use Marana with a simple faceplate, for example on an optical
table. Likewise, while the Marana 4.2B-6 model ships as a standard C-mount, it can be readily converted foruse with F-mount lenses by selecting this additional optical mount accessories when ordering.
For attachment to various professional
telescope configurations, the camera front end
can be direct mounted. For The larger fieldof view Marana 4.2B-11 model, this provides
up to f/# 0.7 with 72º cone angle. Throughengagement with Andor’s Customer Special
Request (CSR) service, custom optical mounts
can be tailored to your specific optical needs.

Figure 7: ‘Direct mount’ front end of Marana 4.2B-11, yielding f/# 0.7 and 72ºCone Angle. Discuss custom mounting flanges with Andor’s CSR Service.

P Marana 4.2B-6 Purchase Flexibility – Don't want to commit to CoaXPress connectivity from the outset?
If preferred, order the less expensive USB 3.0-only version and later avail of a simple in-field upgrade to
CoaXPress capability, if and when you want to unlock the full speed potential of Marana 4.2B-6.

P Timestamp – The Marana platform can generate a timestamp for each image that is accurate to 25
nanoseconds. Accurate timestamps can be important where precise knowledge of frame time impacts
temporal dynamic analysis. This is especially important for fast events, where computer and interface
latencies need to be considered, for example in Pulsar or Solar studies.

P Pixel Size Options - The 11 μm or 6.5 μm pixel sizes of the available Marana models
offer a solution to more closely resolution match the camera to the specific opticalconfiguration. Pixel binning offers further usage flexibility.

P Fast Spectroscopy Mode – Marana 4.2B-6 and Marana 4.2B-11 can be readily
adapted to the needs of fast spectroscopy, yielding up to greater than 25K spectra/sec. Such spectral rates
are ideal for following fast reaction dynamics on sub-millisecond, stopped flow experiment timescales. Fast
spectral kinetics capability can also be used for ‘pseudo-gated’ time-resolved functionality, whereby the firstseries of spectra from a fast series can be discarded to ‘gate out’ the effects of the initial exciting laser pulse.
Max Frame Rate (fps)ROI area

Example scenarios of use

ROI Size (W x H)

16-bit12-bit(of sensor)

2048 x 1200

4181

22.5mm x 13.2mm

High density multitrack on Kymera/Shamrock

2048 x 8

5415

9747

22.5mm x 88µm

Single or dual track spectroscopy

2048 x 2

16244

24367

22.5mm x 22µm

Single track spectroscopy

2048 x 1

24367

24367

22.5mm x 11µm

Single track spectroscopy with ultrafast rates

Table 3: Selection of Marana 4.2B-11 Region of Interest (sub-array) configurations that can be readily harnessed for rapid spectroscopic applications.
On-camera FPGA pixel binning for optimal photon collection is complimented by a bit depth of 32- bit for extended dynamic range.

P Adaptive Optics Ready – Marana readout is well
suited to the needs of AO Wavefront Sensing, with ROIROI Size (W x H)

usage readily achieving several hundred frames/sec.
Furthermore, it is highly important in AO to be able
to react to information with minimal latency. Marana
sends data from each row as soon as the row is readout, it does not wait until an entire image is captured
and assembled on the camera before transmission
through the interface. Thus AO researchers can begin

Max Frame Rate (fps)
16-bit12-bit (Low Noise)1024 x 1024

148

87

512 x 512

295

174

256 x 256

587

346

128 x 128

1166

687

processing and using the info, row at a time.
Table 4: Selection of Marana 4.2B-6 Region of Interest (sub-array) configurations that can be readily harnesses for Adaptive Optics Wavefront Sensing.

Marana 7 Reasons
7. UV/Blue Sensitivity
Marana 4.2B-11 and Marana 4.2B-6 offer great QE across the 200 - 400nm region. This represents
high QE solutions for both 266 nm and 355 nm laser lines. Experiments that can benefit from enhanced
UV sensitivity include Semiconductor Wafer Inspection (266nm), UV Raman and LIDAR. The enhanced
blue response is also well suited to some ultra-cold trapped ion experiments, primarily for quantum
computing, e.g. Ytterbium, Calcium and Magnesium.
Note, for optimal UV sensitivity, please order Marana with the UV-responsive window option, ‘VUV-NIR’

Figure 8: Marana 4.2B-11 and Marana 4.2B-6 QE curves.