1. The Adaptive Gain Integrating Pixel Detector
Allahgholi1, J. Becker1,7, A. Delfs1, R. Dinapoli2, P. Göttlicher1, H. Graafsma1,5, D. Greiffenberg2, H. Hirsemann1, S. Jack1, A. Klyuev1, H. Krueger4, M. Kuhn1, S. Lange1, T. Laurus1,
A. Marras1, D. Mezza2, A. Mozzanica2, J. Poehlsen1, S. Rah6, B. Schmitt2, J. Schwandt3, I. Sheviakov1, X. Shi2, U. Trunk1 , Q. Xia1, J. Zhang1, M. Zimmer1
1 – Deutsches Elektronen-Synchrotron, 2 – Paul Scherrer Institute, 3 – Universität Hamburg, 4 – Universität Bonn, 5 – Mid Sweden University, 6 – Pohang Accelerator Laboratory, 7 – now at Cornell University, Ithaca, NY
Challenges of new synchrotron and FEL sources
AGIPD in a nutshell
With the increased brilliance of state-of-the-art synchrotron radiation sources and the advent of Free Electron Lasers (FELs), enabling revolutionary science with X-ray photons comes an urgent need for suitable photon imaging detectors. Requirements include high frame rates, very large dynamic range, single-photon counting capability with low probability of false positives, and (multi)-megapixels.
Here we present AGIPD, a state-of-the-art detector system tackling the challenges of modern Free Electron Laser sources and their user´s needs:
Single photon sensitivity
High dynamic range
High frame rates
AGIPD
Operating principle
Charge integrating
Energy range
3 keV-18 keV
Frame rate
> 4.5 MHz (burst)
Memory depth
352 frames
Pixel size
(200 µm)²
Pixel technology
Hybrid Pixel Technology
Total detector size
Variable (modular)
Module size
2.5  10.5 cm², 128  512 pixels
Dynamic range
1 to 104 photons/pixel/frame at 12.4 keV
Dynamic gain switching
Yes (3 gains)
Veto/Trigger
Yes (overwriting of frame RAM)
Single Photon sensitivity
Yes (in high gain)
from TDR Eu-XFEL [1]
AGIPD
First User European XFEL
The experiment:
Powder diffraction from LiTi (left)
Liquid jet with crystals (right)
Automatic indexing (centre)
Frame rate 4.5 MHz
30 1.1MHz/train
E=8keV
Adaptive Gain Integrating Pixel Detector
XFEL time structure
Designed for use at the European XFEL, AGIPD comes along with three key features:
Single photon sensitivity
Dynamic range of up to 104 photons/pixel/frame.
4.5 MHz repetition rate (for 352 images)
Store
Read-out
Store
Read-out
Store
352 Images
The AGIPD 1.1 ASIC
AGIPD 1.0
Pixel (4096)
Readout chain
CDS stage
Preamplifier stage
Cf, high
Cf, mid
Cf, low
Preamp RST
Ccouple
CDS RST
Cf, CDS
Vref
Dynamic
gain
switching
DAC
Storage
cell matrix
Pixel buffer
PXB RST
Cf, PXB
Double column
buffer (64)
even row
odd row
Mux
Offchip drver
(4)
Cmd based IF, periphery, DACs
The AGIPD 1Mpix system at the SPB/SFX and MID instruments
The 200µm pixel size of AGIPD is a
compromise between small pixels for high
spatial resolution and storing as many images
as possible.
AGIPD 1M will be operated in vacuum
16 modules are mounted on four independently movable quadrants
Each module has 28 ASICs bump bonded to one Si sensor
Operating temperature -20°C
SPB system shipped to EuXFEL
200µm
AGIPD ASIC: Pixel layout (left) and block diagram showing the analogue readout chain [2,3] (top)
Preamplifier with adaptive gain by insertion of additional feedback capacitors to lower sensitivity and increase dynamic range once a defined threshold is crossed
Correlated Double Sampling (CDS) stage to remove reset noise and reduce low frequency noise
Analogue memory, which can store 352 images
Read out of stored signals are through the pixel buffer, column buffer and off-chip driver in between the bunch trains (≈25 ns out of 99 ns)
200µm
200 µm  200 µm pixels
352 storage cells + veto possibilities.
4.5 MHz frame rate
Dynamic range: from ≈265e- to 344  106 e-
Dynamic range and noise performance
Current developments
Gain linear within 1%.
Noise below Poisson Limit for each gain stage.
Signal to noise ratio of 12σ for one 12.4 keV photon in the high gain
Interface electronics redesign
ecAGIPD
Electron collecting AGIPD
Simulations successfully finished
Prototype in production - delivery March
0.5…1 %
Shot-to-shot
fluctuation
Beamline tests at PETRA III
High-Z sensor
Cooperation with University of Tomsk
GaAs sensor prototype in hands
Waiting for ecAGIPD prototypes
Digitisation in vacuum
Onboard DC/DC
Onboard HV generation
Control and DAQ completely based on optical data transmission
Powerful cooling system necessary
7.05 keV photons
Future systems
Image of a colloidal sample, left single image, right time average. The absence of photons is encoded as black colour on the logarithmic scale. Each image contains pixels in all three gain stages simultaneously. Note that no beam stop was used and besides the scattering pattern the direct Synchrotron beam was recorded.
4MPix AGIPD for SFX
Si sensors
56 sensor modules – divided into two halfs
400 mm travel range along the beam
Delivery December 2018
1MPix AGIPD for HiBEF
High-Z sensors
16 sensor modules – one monolithic block
Delivery with Si sensors in November 2018
Upgrade to High-Z in summer 2019
Histogram of the data from a single pixel. The average intensity is 0.3 photons per 200 ns, corresponding to a count rate of 1.5 Mcps/pixel or 37.5 Mcps/mm2. The RMS noise of this pixel is 320 electrons at 5.2 MHz [4].
Acknowledgments
References
[1] M. Altarelli et al., doi: /
[2] X. Shi et al., Challenges in chip design for the AGIPD detector, doi: /j.nima
[3] U. Trunk et al., AGIPD - The Adaptive Gain Integrating Pixel Detector for the European XFEL. Development and Status, doi: /NSSMIC
[4] J. Becker et al., Performance tests of an AGIPD 0.4 assembly at the beamline P10 of PETRA III, doi: / /8/06/P06007
[5] A. Allahgholi et al., The Adaptive Gain Integrating Pixel Detector AGIPD, J. Instrum. (2015) IWoRiD conference proceedings
F. Westermeier and M. Sprung for experiments and operations at PETRA P10.
I. Vartanians, U. Lorenz, A. Singer, K. Schlage and H.-C. Wille for experiments and operations at PETRA P01.
R. Bradford, D. M. Kline and S. Stoupin for experiments and operations at APS BM1
A. Burkhardt, P. Heuser, J. Kallio, V. Lamzin, V. Mariani, A. Meents, P. Fischer, and M. Kuhn for experiments and operations at PETRA P11