High-resolution digitizer helps in hunt for dark matter

Fig. 1: This CAPP equipment is supplied with an 8 T superconducting magnet. The feeble sign (10−24 W) from the cavity is amplified and transmitted by means of an RF receiver chain with a HEMT amplifier earlier than being despatched for acquisition, evaluation and storage

Fig. 2: In axion search, the alerts from the haloscope are amplified earlier than being acquired by the DAQ.

Fig. 3: The CAPP experimental corridor permits a number of dark matter search experiments to be put in and function on the similar time. The laboratory contains seven low vibration pads for parallel experimental setups, in addition to a number of fridges and superco

Spectrum Instrumentation PC-card permits excessive effectivity search at IBS for axion particles to show dark matter

GROSSHANSDORF, HAMBURG, GERMANY, November 2, 2022 /EINPresswire.com/ — To assist clarify the formation, evolution and conduct of large-scale buildings in the universe akin to galaxies, scientists have predicted the existence of dark matter. In truth, principle means that the universe may very well comprise as much as 5 occasions extra dark matter than odd matter! While the query of what truly makes up dark matter stays unanswered, scientists have recognized various candidate particles. Some of the extra promising ones are axions which may be only a ten-trillionth of the mass of an electron. In South Korea, on the Institute for Basic Science (IBS), they’ve assembled a crew of specialists to check and attempt to discover axions. A quick PCIe-digitizer by Spectrum Instrumentation was chosen for the most recent and most superior experiments.

It is predicted that axions will convert into photons in the presence of a powerful magnetic area. So, the Korean crew has constructed a brand new laboratory that makes use of tremendous highly effective magnets to try to create that exact state of affairs. Imaging of the phenomenon is finished utilizing a haloscope, that in flip makes use of a quick information acquisition system (DAQ) to seize, analyze and retailer the outcomes.

At CAPP, the Center for Axion and Precision Physics Research on the IBS, the plan is to conduct quite a lot of experiments over the approaching decade to verify the existence of axions and finally decide their properties. The first experimental outcomes are already in. The crew at CAPP has searched for axions with a mass between 6.62 and 6.82 μeV that correspond to the frequency between 1.6 and 1.65 GHz. The search was made utilizing the CAPP equipment proven in determine 1. The researchers confirmed experimentally with a 90% confidence stage, which is probably the most delicate outcome in the mass vary so far, that there isn’t any axion dark matter or axion-like particle inside that vary.

A key part of the laboratory’s most just lately applied information acquisition system is a Spectrum Instrumentation PCIe Digitizer card, mannequin M4i.4470-x8. The scientists selected this unit as it may pattern the incoming alerts on two channels concurrently, at charges as much as 180 MS/s and with 16-bit vertical decision. Importantly, the collected information might be streamed to a pc, over the PCIe bus, at a switch pace in extra of three GB/s. This implies that the entire information might be acquired and despatched to the host pc with none of it being misplaced. A block diagram of the standard experimental setup is proven in determine 2.

Dr. ByeongRok Ko, Research Fellow at CAPP, explains, “Our aim was to improve the figure of merit in axion haloscope searches, i.e., the scanning rate. First, we realized a practical DAQ efficiency of greater than 99% for a single channel, where the DAQ process includes the online Fast Fourier Transforms (FFTs). Then, using an IQ mixer and two parallel DAQ channels, we implemented software-based image rejection without losing the DAQ efficiency. This is more than twice the efficiency of earlier setups, which were based on using a conventional spectrum analyzer.”

Image rejection is essential as axion haloscope searches usually make use of a heterodyne receiver which introduces undesirable picture backgrounds. As such, picture rejection turns into important for sustaining a excessive scanning charge. In this case, the quick DAQ system offers a picture rejection of about 35 dB, over a frequency vary from 600 to 2200 MHz. “There are two important features of the Spectrum digitizer card that enable this which is why we chose it,” says Dr. ByeongRok Ko. “First, the on-board memory of 2 GSamples, which can be used as a buffer, and second, a FIFO transfer mode over the PCI Express x8 Gen2 interface, that allows the continuous data streaming at speeds of greater than 3 GB/s.”

Another problem for the DAQ system is the put up processing of the info. This contains unit conversion, on-line FFT, averaging, and writing the facility spectra to disk storage. The on-line FFT dominates the put up processing time. In most circumstances, axion haloscope experiments require information at completely different resonance frequencies as a result of the axion mass is unknown. Also, for varied causes, the info at every resonance frequency might be divided into a number of subsets at completely different timestamps. In such circumstances, the put up processing might be carried out in parallel whereas the following information is being acquired. Fortunately, the Spectrum Instrumentation digitizers include drivers that assist a variety of programming languages, one among which is Python. Python’s multiprocessing module is good for this sort of utility and was subsequently used to show the above state of affairs.

Yannis Okay. Semertzidis, the director of CAPP and in addition a professor of KAIST (Korea Advanced Institute of Science & Technology), explains, “This experiment is not a 100-meter sprint but the first goal in a marathon run. We learned by doing it, and we tested new concepts to be used at higher-level systems in the future.” The crew proved they’ll attain significantly better sensitivity than all different experiments beforehand achieved over the goal frequency vary. The plan now could be to scale up their experiments with bigger techniques.

To speed up the search course of, the crew at CAPP now runs a number of experiments utilizing quite a lot of system designs. This permits the focusing on of various axion mass ranges in parallel. Figure 3 exhibits a panoramic view of the CAPP experimental corridor with its a number of experimental setups. Interested readers can comply with the experimental progress on the CAPP web site at https://capp.ibs.re.kr/html/capp_en/

A analysis paper that discusses the event of the DAQ system, along with the varied acquisition modes and take a look at outcomes, is out there right here:

https://iopscience.iop.org/article/10.1088/1748-0221/17/05/P05025/meta

Press package might be downloaded right here: https://spectrum-instrumentation.com/dl/20221102_high-resolution_digitizer_helps_in_hunt_for_dark_matter.zip

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Sven Harnisch
Spectrum Instrumentation
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