arXiv subjects

V. Patel

Publications and source records attributed to V. Patel.

8 recordsLinked to original sources

arXiv2026

Heat load measurements for the PIP-II pHB650 cryomodule

Phase-3 testing of the pHB650 cryomodule at the PIP-II Injector Test Facility was conducted to evaluate the effectiveness of heat load mitigations performed after earlier phases of testing and to continue pinpointing any sources of unexpectedly high heat loads.. The programme measured HTTS, LTTS, and 2 K isothermal/non-isothermal loads under "standard", "linac", and "simulated dynamic" operating modes, recording data both inside the cryomodule and across the bayonet can circuits. Thermal-acoustic oscillations were eliminated by replacing the original G10 cooldown-valve stem with a stainless-steel stem fitted with wipers. A newly developed Python script automated acquisition of ACNET data, performed real-time heat-load calculations, and generated plots and tables that were posted to the electronic logbook within minutes, vastly reducing manual effort and accelerating feedback between SRF and cryogenics teams. Analysis showed that JT heat-exchanger effectiveness and temperature stratification in the two-phase and relief piping strongly influence the observed loads and helped isolate sources of excess heat. The campaign demonstrates that rigorous pre-test planning, real-time diagnostics, and automated reporting can improve both accuracy and efficiency, providing a template for future PIP-II cryomodule tests and for implementing targeted heat-load mitigations.

physics.acc-ph↗

arXiv2025

Integration and commissioning plan of Full Flow Purifier at Muon Campus

The Full Flow Purifier for Fermilab's Muon Campus uses a charcoal bed surrounded by a liquid nitrogen jacket to purify up to 240 g/s of helium gas. Fabrication by Ability Engineering Technology Inc. has been completed and the purifier delivered to Fermilab. It is the largest purifier to be used at Fermilab based on both capacity and size. A previous paper discussed the design of purifier for various operational conditions and horizontal shipping. The purifier is designed to withstand 5g force in vertical and 2g force in lateral and longitudinal directions. Transportation experience from vendor to Fermilab and within site is discussed. Integration of the purifier involved design and fabrication of a liquid nitrogen transfer line, regeneration system, and helium piping to connect it to Muon Campus cryogenic system. It also involved establishing electrical, instrumentation and controls connections to the system. Integration of the purifier is discussed in detail. The purifier is to be commissioned using up to 4 MYCOM helium compressors to supply helium and liquid nitrogen supplied by a 60,000-liter tank. Actual effectiveness of the 3-stream heat exchanger is to be estimated based on measured temperatures and flow rate. Impurity levels will be monitored at inlet and outlet of the purifier. Theoretical adsorption capacity of the purifier is calculated based on the measured temperatures and flowrates and is compared to actual adsorption capacity over time.

physics.acc-ph↗

arXiv2025

Series Testing and Characterization of 1100 Hamamatsu H12700 Multianode Photomultiplier Tubes

Both the future CBM-RICH and the recently upgraded HADES-RICH use Hamamatsu H12700 Multi-Anode Photomultipliers (MAPMTs) as their photon detectors. To test the MAPMTs thoroughly before using them in the detectors, the photon sensors were qualified well in advance and a test bench was built to efficiently characterize each MAPMT. The test bench measures the single photoelectron gain, dark rate, relative efficiency, and afterpulse probability of each channel. This article describes the operating principle of the test bench and discusses the distributions of each measured quantity over 1,100 MAPMTs. Additionally, the long-term aging effects of the H12700 MAPMT are investigated based on repeated measurements of individual MAPMTs.

physics.ins-det↗

arXiv2024

Performance of PIP-II High-beta 650 Cryomodule After Transatlantic Shipping

After shipment to the Daresbury Lab and return to Fermilab, the prototype HB650 cryomodule underwent another phase of 2K RF testing to ascertain any performance issues that may have arisen from the transport of the cryomodule. While measurements taken at room temperature after the conclusion of shipment indicated that there were no negative impacts on cavity alignment, beamline vacuum, or cavity frequency, testing at 2K was required to validate other aspects such as tuner operation, cavity coupling, cryogenic system integrity, and cavity performance. Results of this latest round of limited 2K testing will be presented.

physics.acc-ph↗

arXiv2023

Nitrogen Precooling Heat Exchanger replacement and control system upgrade in Superfluid Cryoplant at CMTF

Liquid Nitrogen precooling is used in most Cryoplants to achieve cooldown to 80 K temperature range. In one such system at Fermilab's CMTF Superfluid Cryoplant, where the Helium supply directly exchanges heat with liquid Nitrogen, freezing of Nitrogen occurred inside the heat exchanger due to heat exchanger imbalance during a Cryoplant trip. Trapped vapor pockets of N2 within the frozen heat exchanger channels were formed while warming up the heat exchanger, creating high localized pressure and subsequent damage/rupture of the heat exchanger. Replacement of the heat exchanger was done, and modifications were made in the system to rectify future occurrences. The control system was updated to bypass the heat exchanger entirely if the incoming Helium stream temperature drops below 76 K. This was done by repurposing two control valves as heat exchanger bypass valves that were previously used for a redundant 80 K adsorber in the coldbox. Additional modifications were made to further prevent return of large amount of cold Helium gas from cold end during abrupt Cryoplant shutdown. This modification has ensured high reliability of heat exchanger with prevention of freezing of Nitrogen which can damage the heat exchanger.

physics.ins-det↗

arXiv2020

Production and electromagnetic decay of hyperons: a feasibility study with HADES as a Phase-0 experiment at FAIR

A feasibility study has been performed in order to investigate the performance of the HADES detector to measure the electromagnetic decays of the hyperon resonances $\Sigma(1385)^0$, $\Lambda(1405)$ and $\Lambda{\Lambda}(1520)$ as well as the production of double strange baryon systems $\Xi^-$ and $\Lambda\Lambda$ in p+p reactions at a beam kinetic energy of 4.5 GeV. The existing HADES detector will be upgraded by a new Forward Detector, which extends the detector acceptance into a range of polar angles that plays a crucial role for these investigations. The analysis of each channel is preceded by a consideration of the production cross-sections. Afterwards the expected signal count rates using a target consisting of either liquid hydrogen or polyethylene are summarized.

nucl-ex↗

arXiv2020

A Technology-aided Multi-modal Training Approach to Assist Abdominal Palpation Training and its Assessment in Medical Education

Computer-assisted multimodal training is an effective way of learning complex motor skills in various applications. In particular disciplines (eg. healthcare) incompetency in performing dexterous hands-on examinations (clinical palpation) may result in misdiagnosis of symptoms, serious injuries or even death. Furthermore, a high quality clinical examination can help to exclude significant pathology, and reduce time and cost of diagnosis by eliminating the need for unnecessary medical imaging. Medical palpation is used regularly as an effective preliminary diagnosis method all around the world but years of training are required currently to achieve competency. This paper focuses on a multimodal palpation training system to teach and improve clinical examination skills in relation to the abdomen. It is our aim to shorten significantly the palpation training duration by increasing the frequency of rehearsals as well as providing essential augmented feedback on how to perform various abdominal palpation techniques which has been captured and modelled from medical experts. Twenty three first year medical students divided into a control group (n=8), a semi-visually trained group (n=8), and a fully visually trained group (n=7) were invited to perform three palpation tasks (superficial, deep and liver). The medical students performances were assessed using both computer-based and human-based methods where a positive correlation was shown between the generated scores, r=.62, p(one-tailed)<.05. The visually-trained group significantly outperformed the control group in which abstract visualisation of applied forces and their palmar locations were provided to the students during each palpation examination (p<.05). Moreover, a positive trend was observed between groups when visual feedback was presented, J=132, z=2.62, r=0.55.

cs.HC↗

arXiv2005

Crossover from Kramers to phase-diffusion switching in hysteretic DC-SQUIDs

We have measured and propose a model for switching rates in hysteretic DC-SQUID in the regime where phase diffusion processes start to occur. We show that the switching rates in this regime are smaller than the rates given by Kramers' formula due to retrapping of Josephson phase. The retrapping process, which is affected by the frequency dependent impedance of the environment of the DC-SQUID, leads to a peaked second moment of the switching distribution as a function of temperature. The temperature where the peaks occur are proportional to the critical current of the DC- SQUID.

cond-mat.supr-con↗