Multichannel read-out for arrays of metallic magnetic calorimeters
F. Mantegazzini, S. Allgeier, A. Barth, C. Enss, A. Ferring-Siebert, A. Fleischmann, L. Gastaldo, R. Hammann, D. Hengstler, S. Kempf, D. Richter, D. Schulz, D. Unger, C. Velte, M. Wegner
MMultichannel read-out for arraysof metallic magnetic calorimeters
F. Mantegazzini , S. Allgeier , A. Barth , C. Enss , A. Ferring-Siebert ,A. Fleischmann , L. Gastaldo , R. Hammann , D. Hengstler , S. Kempf ,D. Richter , D. Schulz , D. Unger , C. Velte , and M. Wegner Kirchhoff-Institute for Physics, Im Neuenheimer Feld 227, 69120Heidelberg, Germany. Institute of Micro- and Nanoelectronic Systems, Karlsruhe Institute ofTechnology, Hertzstraße 16, 76187 Karlsruhe, Germany. * Corresponding authors
Abstract
Metallic magnetic micro-calorimeters (MMCs) operated at millikelvin tempera-ture offer the possibility to achieve eV-scale energy resolution with high stoppingpower for X-rays and massive particles in an energy range up to several tens ofkeV. This motivates their use in a wide range of applications in fields as particlephysics, atomic and molecular physics. Present detector systems consist of MMCarrays read out by 32 two-stage SQUID read-out channels. In contrast to the designof the detector array and consequently the design of the front-end SQUIDs, whichneed to be optimised for the physics case and the particles to be detected in a givenexperiment, the read-out chain can be standardised. We present our new standard-ised 32-channel parallel read-out for the operation of MMC arrays to be operatedin a dilution refrigerator. The read-out system consists of a detector module, whosedesign depends on the particular application, an amplifier module, ribbon cablesfrom room temperature to the millikelvin platform and a data acquisition system.In particular, we describe the realisation of the read-out system prepared for theECHo-1k experiment for the operation of two 64-pixel arrays.The same read-out concept is also used for the maXs detector systems, developedfor the study of the de-excitation of highly charged heavy ions by X-rays, as wellas for the MOCCA system, developed for the energy and position sensitive detec-tion of neutral molecular fragments for the study of fragmentation when molecularions recombine with electrons. The choice of standard modular components for theoperation of 32-channel MMC arrays offer the flexibility to upgrade detector mod-ules without the need of any changes in the read-out system and the possibility toindividually exchange parts in case of damages or failures. a r X i v : . [ phy s i c s . i n s - d e t ] F e b Introduction
Arrays of low temperature micro-calorimeters are the ideal device for high resolutionspectrometry [1] [2]. At the same time the achieved performances make them interestingalso for other fundamental research fields, ranging from molecular to nuclear, particleand astroparticle physics, as well as for applications like nuclear forensics and materialanalysis. Among them, metallic magnetic calorimeters have demonstrated not only anexcellent energy resolution, but also a reliable energy calibration over the full energy rangethey are designed for, e.g. from a few tens of eV to 100 keV, as well as a fast responsetime below 100 ns [3] [4] [5].Metallic magnetic calorimeters (MMCs) are composed of an energy absorber, opti-mized in size and material to have high absorption efficiency for the physics case of theparticular experiment, a paramagnetic temperature sensor in a constant magnetic fieldwhich is thermally tightly connected to the absorber and whose magnetisation is stronglydependent on temperature, finally a thermal link to a thermal bath, which defines theidle temperature of the detector, typically in the range of 10 mK to 50 mK. A super-conducting coil, well magnetically coupled to the sensor, is used both for providing theconstant magnetic field thanks to a persistent current and as a pick-up coil for the de-tection of magnetisation change in the sensor following a change of temperature of thedetector. An often used geometry for the superconducting pick-up coil is a planar mean-dering stripe of niobium right underneath the paramagnetic temperature sensor. In manyof our detectors two of such meander-shaped coils, reading out two sensors, are connectedin parallel to each other and in parallel to the input coil of a current-sensing dc-SQUID,used to transduce the change of magnetisation in the sensor into a change of voltage.This configuration forms a gradiometer of first order, allowing to assign each event tothe correct pixel thanks to the different polarity. Moreover, the influence of backgroundfields and of temperature fluctuations of the thermal bath are significantly suppressed. Adouble stage SQUID read-out [16] is used to reduce the effect of the noise from the roomtemperature electronics. The second stage typically consists of a series array that act aslow temperature pre-amplifiers.Over the last 10 years magnetic micro-calorimeter arrays have been developed for alarge variety of experiments. For each of the different applications, a dedicated optimi-sation of the MMC single pixel is performed which in the end leads to an array designtailored to the physics case of the particular experiment. For many applications, arraysconsisting of 64 pixels, which correspond to the readout of 32 double meanders, repre-sent a very good compromise between the active detector area and the feasibility andcomplexity of parallel read-out.Figure 1 shows three examples of MMC arrays which are read out using 32 two-stageSQUID channels. Figure 1 a) shows a maXs-30 array. This array has been originally opti-mised for the detection of X-rays produced in atomic transitions in stored highly chargedheavy ions [6] [7]. The aim of such measurements is to test QED in extreme conditionswhere the electric field in which the bound electron is moving close to the Schwinger limit.The active detector area is 4 mm × Th we used an absorber thickness of 20 µ m which corresponds to aquantum efficiency of at least 65% for photon energies up to 30 keV. The device reachesan energy resolution below 10 eV at 60 keV, the highest resolving power achieved with2 mm (a) . mm (b) mm (c) Figure 1: a) Photograph of the maXs-30 detector array for detection of X-rays with energiesup to 30 keV, b) photograph of the MOCCA detector with 4096 pixels for positionsensitive detection of neutral molecular fragments, c) photograph of the ECHo-1kdetector array designed to reach high energy resolution in order to measure thecalorimetric electron capture spectrum of
Ho for the determination of theelectron neutrino mass [11]. any type of micro-calorimeter so far. The first results for the isomer energy of
Th havebeen recently been presented in [8].Figure 1 b) shows a MOCCA array consisting of 4096 pixels covering a surface of44 . × . Ho for thehigh energy resolution measurement of the electron capture spectrum [11] [12]. This chiphas been designed for the first phase of the ECHo experiment at the end of which, thanksto the analysis of a
Ho electron capture spectrum with a number of
Ho events of theorder of 10 , an improved limit on the effective electron neutrino mass can be achieved.The three applications just described require very different MMC arrays but they areall operated in a dilution refrigerator and require all identical read-out infrastructure.3his highlights the benefit of having standard components for the installation of thedetectors in a dilution cryostat which implies to define standard interfaces between thedetector module, which contains the chip with the detector array and the front-end dc-SQUIDs, and the amplifier module, which contains the SQUID arrays for low temperatureamplification of the signals from the front-end SQUIDs. The two-stage SQUID read-outis controlled by room temperature electronics connected directly to the cryostat throughvacumm feedthroughs located at the top flange of the cryostat. For each channel 10 wiresare required for operating array and front-end SQUID. Ribbons with 30 wires have beendesigned to connect the amplifier modules to the room temperature electronics.We describe the read-out system developed for the operation of 32 MMC channelsand discuss the motivation for the choice of standard parts. In particular, the read-outsystem developed for the experiment ECHo-1k will be presented in detail. In conclusion,we report a summary of the characterisation of all the channels which have been used forthe ECHo-1k high-statistics measurement. In the following a close look to the ECHo detector is presented, as an example for the vari-ety of detectors. The detector chip for the first phase of the ECHo experiment, ECHo-1k,consists of an MMC array by a total of 36 SQUID read-out channels [12]. Two of thechannels on the chip are devoted to test purposes, namely detector diagnostics and chara-cterisation, two channels are dedicated to temperature monitoring and the remaining 32channels can be used for measuring the
Ho spectrum after the source is embeddedvia ion-implantation [13]. Each SQUID channel reads out two meander-shaped pick-upcoils [14], as described above, arranged in a gradiometric configuration allowing for theidentification of the pixel where a particle event occurred via the polarity of the signal.Moreover, the gradiometric setup makes the MMC channel fairly insensitive to fluctua-tions of the substrate temperature, as the temperature variations happen simultaneouslyin both pixels. In order to operate the detector, a persistent current is injected in themeander loop by means of a dedicated persistent current switch, which is used to locallybreak the superconductivity of the closed niobium loop formed by the two pick-up coils[12].The chip size is 10 mm × copper with a size of 2 . × . × . Oxygen Free High Conductivity. ircuit boardECHo-1k detectorand front-end SQUID chips16-pin connectorsCopper holder
25 mm
A B C DE FG
Figure 2:
ECHo-1k detector sample holder made of copper, mostly covered by a circuit boardwith white solder mask. In the inset a close-up view on the ECHo-1k detector chip(A) glued onto the holder is shown. The detector chip is wire-bonded to fourfront-end SQUID chips (B), each one containing 8 SQUID channels, which are gluedon separate copper blocks (C). The gold wire-bonds connecting the on-chip thermalbaths with the copper holder (D) as well as the aluminium wire-bonds betweendetector chip and circuit board (E), between detector chip and front-end SQUIDchips (F) and between front-end SQUID chips and circuit board (G) are visible. replaced. The SQUID chips are electrically connected to the detector via aluminiumwire-bonds bridging the slits that separate the SQUID copper blocks from the detectorholder (figure 2, C). The SQUID chips are wire-bonded to the detector on one side andon the other side to a customised double layer circuit board (figure 2, D), which is fixedon top of the copper holder. The bond-pads at the bottom periphery of the detector arededicated to the persistent current injection and they are directly wire-bonded to copperlines on the circuit board (figure 2, B).The T-shaped detector holder can be inserted in an aluminium shield, as shown infigure 3. The shield becomes superconducting for temperatures below 1 . : eight of themare connected to the SQUID lines and one is connected to the lines dedicated to theinjection of the persistent current in the pick-up coils. Four wires are necessary to read-out each front-end SQUID channel and therefore each SQUID connector corresponds tofour front-end SQUID channels. The front-end SQUID output signals are transferred tosecond stage SQUIDs via tin-coated copper wires which connect the SQUID connectors onthe detector circuit board to the second stage module, as visible in figure 3. The wires are Connector type SHF-108-01-L-D-TH produced by Samtec, 520 Park East Boulevard, New Albany,IN 47150, USA. . The secondstages consist of 16 SQUID-series arrays and acts as a low temperature amplifier stage.The working principle of a two-stage SQUID read-out and the custom-built amplificationmodule will be described in the following section. A m p l i fi e r m o d u l e s Copper holderAluminium shieldRibbon cables D e t e c t o r m o d u l e Figure 3:
The complete cold part of the ECHo-1k set-up placed on the cryostat mixingchamber plate. It includes the shielded detector module and the amplifier stage.
The scheme of a two-stage dc-SQUID configuration is depicted in figure 4. The signalfrom the MMC detector is coupled to a front-end dc-SQUID, the output of which iscoupled into the input of a second-stage SQUID array (i.e. 16 dc-SQUIDs in series) thatserves as low noise amplifier [15]. The SQUID response is linearised by a flux-locked loop(FLL) feedback mechanism applied to keep the front-end SQUID at a constant workingpoint [16]. In the two-stage set-up the front-end SQUID is operated in voltage bias modeby choosing the load resistor much smaller than the dynamical resistance of the front-end SQUID, to decrease the power dissipation on the SQUID chip and, in turn, on thedetector chip. The second-stage amplifier SQUID array is operated in current bias mode.The design and fabrication of front-end and amplifier SQUIDs are tailored to the specificrequirements for MMC detectors [15]. In particular, the input coil inductance of thefront-end SQUIDs is designed to match the inductance of the detector meander-shapedpick-up coils.The pick-up coils of the detector and the input coil of the SQUID are connected bysuperconducting aluminium wires to form a completely superconducting circuit. Changesin external magnetic fields or vibrations of the bonding wires can generate currents in thisloop that lead to an increased noise level. An optimised bonding scheme where on bothchips, SQUID and detector, one of the two bond pads is duplicated has been developed, Produced by Samtec. The SQUID chips are designed and fabricated in house at the Kirchhoff-Institute for Physics, Hei-delberg University. A - st stage 2 nd stage Room temperature electronics I b1 M iS M fb R g I φ X R fb V F S MMC M φ X M iA I b2 I φ b Figure 4:
Schematic drawing of a two-stage SQUID configuration, where the first stage ismarked in violet, the second stage is marked in blue and the room temperatureelectronics is marked in orange. as shown in figure 5. When the resulting three sets of bond pads are connected withbonding wires, the arrangement of these wires represents a gradiometer of first order forthe pickup of external magnetic fields. This layout can reduce the additional noise bynearly one to two orders of magnitude. F F BondpadsBonding wiresSQUID L S L m L i (a) DetectorbondpadsSQUIDbondpadsSQUIDinput coil Stripline (b)
Figure 5: a) Schematic sketch of the optimised three-bond scheme which allows for reducedpickup of external magnetic fields. The magnetic fluxes Φ and Φ are generatingcurrents with the same magnitude but with opposite polarity, leading to a firstgradiometer layout and therefore to the cancellation of additional signals. b)Microscope picture of double aluminium wire bonds that connect SQUID anddetector using the optimised three-bond scheme. While the front-end SQUID chips are glued onto the detector holder and wire-bondedto the detector chip, the second-stage amplifier SQUIDs are placed on separate custom-designed modules to reduce power dissipation to the detector module, operated at about20 mK. The modules are based on the custom-made circuit boards shown in figure 6.Each circuit board is equipped with: • six dc-SQUID array chips with a size of 3 mm × Produced by Multi Leiterplatten GmbH, Brunnthaler Straße 2, D-85649 Brunnthal - Hofolding,Germany.
7f dc-SQUIDs, glued to the circuit board at the end of a 45 mm long circuit boardfinger and wire-bonded to the copper leads; • three double row 16-pin connectors connect to the front-end SQUIDs shown infigure 6a; • four double row 30-pin connectors to which the ribbon type cables (described insection 4) that connect the amplifier SQUIDs to the room temperature read-outstage are plugged.The circuit board is inserted into a tin-plated copper case. This case consists oftwo copper plates that are coated with about 8 µ m thick layer of tin. Due to its highthermal conductivity, copper ensures a reliable thermalisation of the heat produced bythe amplifier SQUIDs. On the other hand, tin enters the superconducting regime at 3 . . ◦ C. Pure indium melts at157 ◦ C and pure tin at 232 ◦ C. To prepare the diffusion welding both plates are pressedto each other with indium wires of 1 mm diameter placed in between them. The indiumwires were positioned as shown in figure 6b. In pressed state the plates are baked forthree hours at 140 ◦ C in air at normal pressure.The circuit board is attached to the module case with five screws at the connector side.Therefore, the six fingers of the circuit board can potentially be subjected to vibrations.To prevent that, they are additionally fixed to the module exploiting tinned M 1.6 grubscrews inserted into the threads in the upper part of the module, close to the amplifierSQUID chips.Three amplifier modules, corresponding to 36 read-out channels, can be stacked form-ing a compact tower, which can be mounted on the mixing chamber plate of a dilutionrefrigerator, as depicted in figure 7a. The amplifier modules are additionally surroundedby a cryoperm shield . This soft magnetic shield allows for a reduced background mag-netic field during the transition of the tin parts to the superconducting state. The ECHo detectors are operated in a dedicated dry dilution refrigerator of type BF-XLD that reaches a base temperature below 7 mK. This cryostat has a cooling powerof 20 µ W at 20 mK at the mixing chamber plate. Along with the capability to host anet load of about 200 kg, the large available experimental space - corresponding to acylindrical volume with a diameter of 50 cm and a height of 50 cm below the mixing Connector type SHF-108-01-L-D-TH produced by Samtec. Connector type TFM-115-01-S-D produced by Samtec. Produced by Magnetic Shields Ltd, Headcorn Rd, Staplehurst TN12 0DS, UK. Produced by BlueFors Cryogenics Oy, Arinatie 10, 00370 Helsinki, Finland. QUIDsconnectors AmplifierSQUIDs chipsUpper shieldSQUID electronicsconnectors Indium wireBottom shield Threaded holesfor grub screws (a)
Steel-PlatePVC-FrameBottomShielding-PlatePVC-FrameIndium-Wire (b)
Figure 6: a) A single array module consisting of the custom made circuit board inserted inthe bottom half of the tin plated copper shield. The upper part is placed on top toclose the module. b) Set-up for the fabrication of the superconducting shield. Theindium wires are positioned on the bottom plate before pressing the second plate ontop of it and proceed with the diffusion welding of the two parts. chamber plate - and the continuous operation, the cryostat is suitable for the current andfuture phases of the ECHo experiment.Figure 7a shows the open cryostat equipped with the cabling described in the following.The wiring consist of 64 parallel SQUID read-out channels and 8 multi-purpose read-outchannels for a total of 72 read-out channels that have been installed in the cryostat andexploited to operate two ECHo-1k detector chips in parallel during the ECHo-1k highstatistics measurement campaign.Two stacks of amplifier modules, each containing 36 read-out channels as describedpreviously, are placed on the mixing chamber plate of the cryostat, as can be seen in figure7a. Altogether, 720 wires (10 wires per read-out channel) connect the amplifier stages tothe room temperature electronics. The read-out wires are organised in twisted pairs andtwisted triples interwoven in ribbons, each one containing the 30 wires required to read-out three SQUID channels. The ribbons are stably woven with Nomex fibers resulting in13 mm wide, 0 . . . The two ribbon ends are equippedwith connectors: at the room temperature side a 24-pin LEMO connector interfaces avacuum feedthrough followed by the SQUID electronics. At the low temperature side adouble row 30-pin connector matches the connectors of the amplifier modules described Manifactured by DuPont de Nemours GmbH, Hugenottenallee 175, 63263 Neu Isenburg, Germany. Produced by Tekdata Interconnections Limited, Innovation House, The Glades, Festival Way, Etruria,Stokeon-Trent, Staffordshire, ST1 5SQ, United Kingdom. Connector EGG.3B.324.ZLL produced by LEMO, Chemin de Champs-Courbes 28, CH-1024Ecublens, Switzerland. Coupler SGJ.3B.324.CLLPV produced by LEMO. Connector type ”SFM-115-01-S-D” produced by Samtec.
9n section 3 (figure 7c). The wire material is optimised to reach a compromise betweenlow resistance and low thermal conductance, to minimise the contribution to the heatinput. Alloy-30 , an alloy of 2 % nickel in copper, has been chosen. The wires have adiameter of 200 µ m and a length of about 2 . . ×
50 mm × is distributed on the contactarea between ribbon and copper plates and the copper plates. The heat sinks at the twolowest temperature stages have been annealed at 800 ◦ C for 48 hours to remove hydrogenmolecules.The ribbons are connected at room temperature to aluminium boxes on top of thecryostat, where 24-pin vacuum feedthroughs connectors are used as interface betweenthe atmospheric pressure outside and the vacuum inside the cryostat and provide thepossibility to directly plug in the SQUID electronics used for the ECHo experiment .The SQUID electronics can be connected via LEMO cables to the SQUID connector box,a device which serves as power supply for the SQUID electronics and allows for tuning ofthe SQUID parameters via software. Purchased from Isabellenh¨utte, Eibacher Weg 3-5, 35683 Dillenburg, Germany. Apiezon N, M&I Materials Ltd., Hibernia Way, Trafford Park, Manchester M32 0ZD, United Kingdom Connector type SGJ.3B.324.CLLPV purchased from LEMO Elektronik GmbH, Hanns-Schwindt-Str.6, 81829 Munich, Germany. K plate ( T ~ 3.8 K) Mixing chamber plate ( T ~ 10 mK)Detector set-upCold plate ( T ~ 150 mK)Still plate ( T ~ 700 mK) Read-out cables50K plate ( T ~ 50 K) (a) Heat sinkMixing chamber plate Ribbons (b) (c)
Figure 7: a) Open dilution refrigerator dedicated to the ECHo experiment. The temperaturestages, the detector set-up and the parallel read-out cabling are highlighted, b)Copper heat sinks for cable thermalisation trough the cryostat temperature stages,c) A single ribbon cable containing 30 wires for three channels.
All the parameters of the programmable two-stage SQUID electronics can be set by soft-ware . The output voltage of the linearised SQUID signal is transferred from the SQUIDconnector box to two ADC modules using coaxial cables equipped with NIM/Camac stan-dard connectors . Each ADC module is based on a 16-channel digitiser card SIS3316 .The cards can either be read-out via ethernet or via a SIS1100/3100 connection based onan optical gigabit link. If more than one module is used, their clocks can be synchronised,which is essential for coincidence measurements. They feature a maximum sampling rateof 125 MHz per channel and a resolution of 16 bit. Supporting simultaneous acquisitionof data and data transfer to the computer as well as individual asynchronous constant SQUID Viewer provided by Magnicon. Produced by LEMO Produced by Struck Innovative Systeme GmbH, Harksheider Str. 102, 22399 Hamburg, Germany.
The SQUID read-out channels which have been used during the first phase of the ECHoexperiment have been individually characterised. The total read-out system consists of64 two-stage SQUID read-out channels distributed in two separate set-ups, connectedrespectively to two ECHo-1k detectors.The front-end stage is characterised by a current sensitivity of the input coil between1 . . µ A, matching the mutual inductance of the input coilof the amplifier SQUIDs. The average mutual inductance of the front-end feedback coilis 42 . µ A / Φ (41 . µ A / Φ ) with a standard deviation of 3 . µ A / Φ (1 . µ A / Φ ) for thefirst (second) set-up, ensuring a homogeneous voltage response in all the channels of eachset-up.The amplification stages feature an inductance of the input coil of about 11 . µ A / Φ and 8 . µ A / Φ , while the peak-to-peak voltage swing is about 930 mV and 480 mV forthe two set-ups, respectively.The typical white noise level is about 0 . µ Φ / √ Hz and the typical 1/f noise level at1 Hz is estimated around 5 . µ Φ / √ Hz. Figure 8 shows an exemplary noise measurementperformed with a anti-aliasing low-pass filter in order to reach very low frequencies.12 + ] 6 + ] Figure 8:
A noise measurement of a two-stage read-out channel with an MMC detector of theECHo set-up connected. The measurement is performed in the low frequency rangebetween 0 . The typical read-out system for MMC arrays with 32 SQUID read-out channels includesthe detector module, the amplifier module, the cabling from room temperature to thecryogenic platform and the data acquisition system. A standard layout has been definedfor each component of this read-out chain, except for the detector module, which hasto be optimised for the specific detector chip design and has to fulfil the requirementsdefined by the particular application. The resulting read-out system is compatible withdifferent detector modules and, due to the modular approach, offer high flexibility.In order to illustrate the different components of the 32 channels MMC read-out, wehave presented the system developed for the first phase of the ECHo experiment, ECHo-1k. A read-out system for the operation of two ECHo-1k modules has been set up andis schematically depicted in figure 9. The detector chip consists of 36 double meanderchannels including two non-gradiometric channels for temperature monitoring and twotest channels. For the experiment, 32 channels for each of the two chips were connectedto the read-out chain. For each channel the first read-out stage consists of single-stagedc-SQUIDs, specifically designed to match the detector requirements, directly glued ontothe detector holder and wire-bonded to the detector. The second stage consists of a 16 dc-SQUID series array, provides amplification at low temperature and is placed in separatemodules shielded by tin plated copper casings. Both the detector module and the amplifiermodules are screwed to the mixing chamber plate of a dry dilution refrigerator.The cryostat is equipped with two sets of read-out cables, each set consisting of 36read-out channels, connecting the detector module at the mixing chamber stage at a13 ront-end SQUID chips Amplifier SQUID chipsTwo-stage SQUID configuration T ~ - m K ribboncables24-wire cables Computer coaxialcables optical linkor ethernet sub-HD 15connector
Detector chip SQUID electronicsSQUID connector boxADC modules
SQUID control software
DAQ software T ~ K Figure 9:
Schematic layout of the complete read-out chain for the ECHo experiment. Thedirection of the arrows refers to the data transfer (i.e. signal data and controlsignals) flow. temperature of about 20 mK to the room temperature electronics. The wire material andsize have been optimised to guarantee minimal contribution to the heat load. Custom-built copper heat sinks are installed at each temperature stage to ensure reliable cablethermalisation. The room temperature side of the cables is interfaced with the vacuuminside the cryostat trough aluminium casings equipped with vacuum feedthroughs. TheSQUID electronics are plugged to the vacuum feedthroughs on one side and to the SQUIDconnector box on the other side. The signal is then transferred to two ADC modulesbased on 125 MHz sampling rate digitiser cards supporting high signal throughput andindividual asynchronous trigger for all channels. Hardware settings, data acquisition anddata storage are controlled by software, which offers also on-line signal processing andon-line fitting.The same read-out scheme has been installed in further dilution refrigerators, as theone to be integrated at the Cryogenic Storage Ring (CSR) [10] for the operation of theMOCCA detector [9] or the cryostats operated in collaboration with the GSI and the HIJena for the study of highly charged ions with different detectors of the maXs family [6].The availability of standard parts for the read-out of 32-channels MMC arrays allows notonly for well characterised properties of each component, but also for a fast exchange ofdamaged parts.
Aknowledgments
Part of this research has been performed in the framework of the DFG Research Unit FOR2202 (funding under GA 2219/2-2, EN 299/7-2, EN 299/8-1). We acknowledge the sup-port of BMBF under the contract 05P19VHFA1. F. Mantegazzini, A. Barth, D. Schulz,D. Unger, C. Velte and M. Wegner acknowledge the support by the Research TrainingGroup HighRR (GRK 2058) funded through the Deutsche Forschungsgemeinschaft, DFG.14e acknowledge the support of the cleanroom team of the Kirchhoff-Institute for Physics,Heideberg University.
References [1] C. Enss at al.,
JLTP , 137–176 (2000)[2] K.D. Irwin and G.C. Hilton,
Transition-Edge Sensors in: Enss C. (eds) CryogenicParticle Detection.
Topics in Applied Physics , vol 99. Springer, Berlin, Heidelberg(2005)[3] A. Fleischmann et al.,
AIP Conference Proceedings
J. Low Temp. Phys.
Appl. Phys. Lett.
Physica Spripta
T166 : 014054 (2015)[7] M. Lestinsky et al.,
Eur. Phys. J. Spec. Top.
Phys. Rev. Lett.
J Low Temp Phys
Nucl. Instrum. Methods B
EPJ ST , 8 (2017)[12] F. Mantegazzini et al., in preparation (2021)[13] L. Gastaldo et al.,
NIM A , 150-159 (2013)[14] A. Fleischmann, C. Enss, G.M. Seidel,
Topics in Applied Physics
Vol. 99 , 151-214(2005)[15] S. Kempf et al.,
Supercond. Sci. Technol. (2015)[16] J. Clarke and A. Braginski, The SQUID Handbook: Fundamentals and Technologyof SQUIDs and SQUID Systems Weinheim
I (ed) 2004 (New York: Wiley)[17] S. Allgeier,
Master thesis , Heidelberg University (2017)[18] D. Hengstler,