1. Readout System for the Edelweiss Dark Matter search
introduction to the EDELWEISS DM search
signal properties
electronic DAQ setup
DAQ software
first results with the new system

2. physics and principles behind EDELWEISS
Count rate:
< 10-2 evt/kg/day!
WIMP
Scatt. WIMP
Recoil
nucleus  ER ~10 keV
problems:
low event rate
background events by:
β, γ and neutrons
muon induced background
simultaneous measurement of heat and ionization energy
𝑄= 𝐸 𝐼𝑜𝑛 𝐸 𝑟𝑒𝑐𝑜𝑖𝑙
𝐸 𝑟𝑒𝑐𝑜𝑖𝑙 = 𝐸 ℎ𝑒𝑎𝑡 − 𝑁𝑒𝑔𝑎𝑛𝑜𝑣−𝐿𝑢𝑘𝑒−𝐸𝑓𝑓𝑒𝑐𝑡
Ge-Detector at 18mK
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

3. bolometer signals 2 heat signals: rise time ~1ms decay time ~100ms
from NTD thermal sensor
4 ionization sig.: rise time <1µs
decay time ~10ms
from interleaved ring electrodes
ADC-Counts
100 kHz heat channel
𝑥 𝑖 = 1 𝑛 𝑗 𝑎 𝑗
𝑃 𝑖 = 𝑥 𝑖 − 𝑥 𝑖+1
Time in ms
NTD
Time in ms
ADC-Counts
heat pulse
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

4. EDELWEISS-II hardware setup
special requirements:
low noise
low radioactivity
detector
at 18mK
analog amplification at 100K with FET
BBv2:
analog/digital conversion at room temperature
distribution-card:
conversion to ethernet packages,
distribution of commands and clock
data acquisition, triggering and storage (DAQ)
continuous control
inner shielding
cryostat
shielding
electric wire:
ext. clock
optical fibre:
advantage: independent DAQ branches
-> experiment continuous if one component fails
voltage, bias:
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

5. additional time-resolved ionization signal
EDELWEISS 2 → EDELWEISS 3
𝝈<𝟒∙ 𝟏𝟎 −𝟖 pb → 𝝈<𝟐∙ 𝟏𝟎 −𝟗 pb
10 ID-400 detectors → 40 FID-800 detectors
upgraded cryogenics
new inner shield
new cabling
new readout
integrated DAQ
additional time-resolved ionization signal
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

6. new integrated DAQ system1x
FLT = First Level Trigger card, historical name
SLT = Second Level Trigger card
= Master card 1x x
detector
at 18mK
analog amplification at 100K with FET
BBv2:
analog/digital conversion, modify to 40MHz
data acquisition, triggering and storage (DAQ)
continuous control
40x
data acquisition, triggering, clock
also used in Auger and KATRIN
inner shielding
Cryostat
outer shielding
1 integrated FPGA based DAQ electronics
trigger closer to the detector -> faster trigger for the 40MHz signal
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

7. Ionization channel electronics - with resistors or relays
Ionization pulse gives a step function followed by an exponential decay
Ionization pulse gives a step function – no decay
after some time one has to reset with the relays to avoid ADC and capacitor saturation
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

8. sampling of analogue data:
in-house design
bolometer box is the hardware control interface to the detector
receives commands and clock from a distributor card
DACs for applying bias to NTD and voltage to electrodes
6 channels with up to 200kS/s each, 16bit (100kS/s used)
2 channels with 40MS/s, 16bit and 2MS ring-buffer (50ms)
(time-resolved ionization signal)
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

9. time resolved ionization readout
so far: 100kS/s  integrated ionization signal
idea: time resolved ionization channels
 position information of events (z-axis)
implemented: faster sampling  40MS/s
needed:
internal fast trigger for event based readout
(100kS/s ionization pulse triggers readout)
Broniatowski, A.
et al.
Physics Letters B 681 (2009) B C D
surface event with calibration source
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

10. Data volume 40 bolometers x 6 channels x 16 bit x 100 kHz
= 384 Mb/s (+ commands, headers,…)
-> with 1 Gb/s ethernet one can stream all channels
~500 Mb/s for 40 MHz fast channel readout
e.g. readout 4 FIC for 100 µs:
4∙16 𝑏𝑖𝑡 ∙40 𝑀𝐻𝑧 ∙ 100 µ𝑠=256 𝑘𝑏𝑖𝑡
or 0.5 ms transfer time
NTD
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

11. electronic components installed in Modane
300K
100K 1K
100mK
10mK
300K
100K 1K
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

12. Modane Crate – 20x FLT Mini Crate – 4x FLT
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

13. ? Connection scheme Master Card BB1 FLT card (20x) Backplane BB2
FPGA
ALTERA
cyclone II
ring buffer
QDR RAM
commands clock
PCIe interface
Master Card
BB1
Backplane
16x FIFO
BB2
BB1
fiber in/out
up to 6 BBs
BB1
PCIe
BB23
powerful Computer
open SUSE 12.2
graphical user interface
2 programs
readout loop (SAMBA
backend)
ORCA backend ?
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

14. Integration of external detectors Muon-Veto System
1 FLT card is configured to readout the Muon-Veto card Muon-Veto card is connected with a pair of fiber, like a BBv2 FLT sends 48 bit timestamp to Muon Veto Muon Veto attaches 6 bit Veto status and sends 54 bit back FLT checks timestamp if it is still correct
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

15. Muon-Veto readout and processing
FLT in Veto –mode
check timestamp
48 bit timestamp (10µs)
Veto-Card in VME Crate
6 bit Veto status
Crate PC
SAMBA PC
used as trigger/veto signal
, Status 5…0, ERROR
16 bit msb timestamp
16 bit medium sb timestamp
16 bit lsb timestamp
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

16. ORCA based control interface
ORCA is a DAQ software for low-level hardware control/readout and high-level experimental configuration and run control
read / write access to all Crate registers
useful for setup or initialize the Crate e.g. in a test mode, or to crosscheck settings configured by SAMBA
ORCA interface is under development, new functions are implemented at the time.
[Till Bergmann]
Other experiments using ORCA:
e.g. SNO, Majorana, KATRIN, EXO
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

17. SAMBA DAQ System – in-house developed
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

18. trigger algorithm T0: heat channel(s) < T1: ionization channel(s)
3. filter
1. heat signal 100kHz
2. heat signal 500Hz
4. heat trigger
_ _ _
Xi = |Xi+ - Xi-| _
Xi+
Xi-
Xi+1 ….
<
S of N
thresh.
T1: ionization channel(s)
3. subtract plots
1. ionization signal 100kHz
4. filter
5. ion. trigger Ai __
<
< A
S of N
2. teach-in a periode
thresh.
Metadata: trigger rate, noise power, event maximum, event timestamp
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

19. different trigger levels & additional detectors
e.g.:
trigger on all channels (2x heat and 4-6 ionization)
trigger on all heat channels only
trigger on 1x heat and 1x ionization channel
geometrical selection of readout channels
Taking external detectors into account:
muon veto system
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn

20. Projection EDELWEISS-3
40 Bolometer x 6 Channels
16bit ADC, 100kHz
up to 40 MHz time resolved ionization channel
integrated DAQ
optimized shielding
test for EURECA
DAMA/LIBRA (3s)
CRESST (2s)
CoGeNT ROI (90%CL)
CDMS+EDELWEISS (90%CL)
ZEPLIN III (90%CL)
CDMS Low Mass (90%CL)
Xenon10 Low Mass (90%CL)
EDELWEISS-III 3000 kgd(90%CL)
Xenon100 (90%CL)
EDELWEISS-III
(3000 kg.d background free)
Legende fehlt
Trotta et. al. (95%CL)
Buchmueller et. al. (95%CL)
EDELWEISS -- readout system | joint AMS EDELWEISS meeting
Bernhard Siebenborn