1. New detectors are needed! Prototype Characterization
The PERCIVAL soft X-ray detector.
J. Correa
on behalf of the Percival Collaboration a,b,c,d,e,f
Matter and Technologies
Detector Development
Motivations and Goals
Detector Structure
Attenuation Length of Photons in Si and SiO2
1m
Water Window
Other FELs
FLASH
ADC
digital out
sampling & gain selection
address
pixel
matrix
12+1 bits
2 bits
backthinned (~12um)
& -doped epi Si e-
handling wafer
partially-pinned
photodiode
nmos -in p-well (avoid parasitic collection)
shallow doping
Detecting photons in the water window is challenging
(sub-µm absorption lengths for Si and SiO2) Entrance window needs to be minimized, or detector response risks being dominated by higher harmonic photons
Brilliance of photon sources increases Detectors are required capable (at the same time) of:
high dynamic range
1-photon discrimination
New detectors are needed!
PERCIVAL: a collaboration between DESY, STFC, ELETTRA, DLS and PAL.
Primary energy range: <250 eV to 1 keV
Single photon sensitivity
High dynamic range.
100% fill factor (back-illuminated, back-thinned)
Large array ( 2M) of small pixels (27um)
High and uniform QE.
Prototype Characterization
syncrotron beam
pinhole
Percival
diffraction through a circular aperture:
Noise for low flux condition ≤ 15 e-.
Noise for high flux condition < Poisson limit.
Beam-time campaigns at:
PETRA (P04)
Elettra (Twinmic, CiPo)
DLS (I10)
BESSY (PTB)
prelim optical/Fe55 tests at
Phoebe XFEL setup
and of course in CFEL Lab
Response to low energy photons (92eV) matches expectations
response is dominated
by 1st harmonic photons
negligible entrance window
scaling up from prototype to full P2M
scaling up from prototype to full P2M
Full well: 3.5 Me- ~ 50k 250 eV
Full P2M System, under test
Carrier board (re-configurable clocks &control)
PowerBoard (bias & monitoring)
Mezzanine board (stream-out data //10Gb ports.)
DAQ interface (deep switch &multiple DELL R630)
VirtualHDF5 dataset data organization (because a detector does not ends at its ethernet port)
approx scale to the prototype dimension
approx scale to the prototype dimension
P2M sensor
Monolithic Active Pixel Sensor
2 Megapixels (~ 4x4 cm2 imaging area)
27um pixel pitch, embedded lateral overflow circuitry (auto-adaptive gain to incoming flux, per pixel, real time)
2 side-buttable: cloverleaf arrangement of 4 modules around a central hole possible
up to 300 frame/s (prelim. tested up to 100 f/s)
on-chip ADCs (13+2 bits): all-digital output
1st image acquired on P2M sensor (visible light, 660nm)
Backthinned P2M (soft X-ray detection) expected spring 2018
I know it now looks messy at the moment: what do you expect from a lab 1st setup? a) b) c) d) e) f)