Advancement of Langmuir probe-based laser photo-detachment technique for negative ion density measurement in a high-power helicon plasma source.

In the pursuit of precise diagnostics for measuring negative ion density in a helicon plasma source (HPS), a new approach utilizing a radio frequency (RF) broadband transformer-based Langmuir probe is developed specifically for laser photo-detachment (LPD) analysis. This inductively coupled LPD technique is useful for high power RF systems in which capacitive RF noise is in the same scale as the pulsed photo-detachment signal. The signal acquired by this transformer-based probe is compared against the conventional Langmuir probe-based LPD technique, revealing a remarkable enhancement in signal fidelity through an improved signal-to-noise ratio (SNR) achieved by the RF broadband transformer methodology. In addition, the localized hydrogen negative ion density measurements obtained through this probe are harmoniously aligned with the line-averaged negative ion density derived from the cavity ringdown spectroscopy (CRDS) technique. These concurrence measurements highlight the RF broadband transformer-based approach's accuracy in capturing localized negative ion density during helicon mode operation in an HPS setup. Furthermore, the correlation of negative ion density values with RF input exhibits a consistent trend in tandem with background plasma density. Notably, both CRDS and LPD measurements ascertain negative ion densities ranging from ∼5 to 6×1016 m-3 under an RF power of 500-700 W and a pressure of 8 × 10-3 mbar, all under the influence of a 55 G axial magnetic field. These specific parameters represent the optimal operational configuration for effective negative ion production with the present experimental HPS setup. Due to its better SNR, the RF broadband transformer-based Langmuir probe emerges as a useful tool for LPD diagnostics, particularly in the presence of pervasive RF noise.

Observation of non-equilibrium fluctuation in the shear-stress-driven hemoglobin aggregates.

Non-equilibrium fluctuations caused by the rearrangement of hemoglobin molecules into an aggregate state under shear stress have been investigated experimentally. The flow response under the shear stress (σ) corroborates the presence of contrasting aggregate and rejuvenation states governed by entropy production and consumption events. From the time-dependent shear rate fluctuation studies of aggregate states, the probability distribution function (PDF) of the rate of work done is observed to be spread from negative to positive values with a net positive mean. The PDFs follow the steady-state fluctuation theorem, even at a smaller timescale than that desired by the theorem. The behavior of the effective temperature (Teff) that emerges from a non-equilibrium fluctuation and interconnects with the structural restrictions of the aggregate state of our driven system is observed to be within the boundary of the thermodynamic uncertainty. The increase in Teff with the applied σ illustrates a phenomenal nonlinear power flux-dependent aggregating behavior in a classic bio-molecular-driven system.

Overview of diagnostics on a small-scale RF source for fusion (ROBIN) and the one planned for the diagnostic beam for ITER.

India is responsible for the supply of diagnostic neutral beam systems for ITER to diagnose its helium ash during the deuterium-tritium plasma phase using the charge exchange recombination spectroscopy technique. Considering the many first of its kind in terms of technologies and beam development aspects, ITER Indian domestic agency has adopted a strategy of developing the technology and beam experimentation in parallel. On the beam development front three test beds, namely, the ROBIN (Rf Operated Beam source in India for Negative ion research), the TWIN (TWo rf driver-based Indigenously built Negative ion source), and the INTF (INdian Test Facility) are presently in their various phases of operation, optimization, and setting up at IPR, respectively. Experiments related to plasma production, beam production, and acceleration up to 30 keV in volume and surface mode have been performed on ROBIN. The maximum negative hydrogen ion current density to a tune of 27 mA/cm2 is obtained in the surface mode with Cs injection. Optimal source performance requires optimal surface conditions, minimum impurities, careful characterization of the plasma, cesium feed and its redistribution, and optimal wall temperatures of the surfaces of the plasma box and the plasma grid. A combination of probe, optical, vacuum, laser based, electrical, and calorimetric diagnostic measurements enables such a control. At ROBIN, the above diagnostics are being used regularly. The operational and diagnostic experiences on ROBIN shall provide the desired experience and database for operations of TWIN and INTF in the coming years. A large number of conventional and advanced diagnostic techniques are used for plasma and beam characterization. These diagnostics are suitable not only to detect and understand the plasma but also for studies related to impurity evolution. The temporal evolution of impurities significantly impacts the plasma and beam properties. The studies help in establishing correlations between physical parameters and operational parameters to optimize the source performance ensuring adequate safety and investment protection. This paper will present a brief overview of various diagnostics implemented, lessons learned, and the results obtained from ROBIN. In addition, an outline of the diagnostics planned for INTF based on the experience and understandings developed during the present experiments on ROBIN and TWIN and considering the requirements of large systems shall be discussed.

Knowledge, Attitude and Level of Involvement of Married Males in Family Planning.

Background There is an age-old notion that family planning is women's responsibility disregarding the fact that men have equal responsibility in fertility regulation. Although male involvement is getting more recognition, studies on men's role in family planning are very few in the number in this part of the world. Objective To assess the knowledge, attitude and level of male involvement in family planning and to find out the factors associated with male involvement by contraceptive usage. Method A community based cross-sectional study was done from May to July 2021 among 165 currently married male, who had at least one child, living in Singur district of West Bengal. Cluster sampling method was done to select study participants and data were collected by pre-designed pretested questionnaire. Descriptive statistics, multivariable logistic regression was applied and data were analysed applying SPSS software. Result Only 36.4% participants were directly involved in family planning either by using condom or by withdrawal method but 65.5% participants were indirectly involved in family planning through spousal communication either by approving contraceptive use to their spouse or by decision making regarding family planning. Moreover, barrier of contraceptives usage were side effect (27%) and fear of impotence (25.5%). Male involvement was significantly associated with participant's education [AOR (95% CI= 3.63 (1.45-9.05)], caste [AOR (95% CI= 7.06 (2.55-19.51)], number of living children [AOR (95%CI= 5.01(1.95-12.87)], desire for more child [AOR (95% CI=0.34 (.13-.87)] and attitude on family planning [AOR (95% CI= 3.55 (1.41-8.94)]. Conclusion This study identified the prevailing gender norms in rural areas. Advocacy for male involvement in family planning by health personnel during counselling of eligible couples should help in increasing contraceptive coverage in the long run.

Quantification of atomic hydrogen anion density in a permanent magnet based helicon ion source (HELEN) by using pulsed ring down spectroscopy.

In the present work, a permanent magnet-based helicon plasma source (HELEN) is characterized as a negative ion source. A noninvasive diagnostic technique based on cavity ring down spectroscopy (CRDS) is developed to measure the line-integrated negative hydrogen ion (H-) density in HELEN. This paper discusses the experimental results in which negative hydrogen ion density is measured for different magnetic field, pressure, and RF (13.56 MHz) power configurations. It is observed that in high power range (800-850 W), the source is operating in helicon wave heating mode with a background plasma density of ∼1018 m-3 and electron temperature of ∼2 eV. Negative hydrogen ion density is measured by CRDS method and also by optical emission spectroscopic technique. The measured negative ion density is in the range of ∼1016 m-3 under volume mode operational condition even without any use of standard magnetic filter or cesium seeding in the downstream region. The influence of pressure variation (pressure range from 4 × 10-3 mbar to 4 × 10-2 mbar) on negative ion density production is not significant, except for a particular axial magnetic field configuration (55 G) and at 8 × 10-3 mbar pressure, where ∼34% hike is observed.

Development and characterization of a helicon plasma source.

The Helicon Plasma Source (HeliPS) designed and developed at the Centre of Plasma Physics-Institute for Plasma Research is a versatile helicon plasma device, which operates in a wide range of magnetic field configurations from 50 G to 500 G. This device is dedicated to perform a broad range of research activities. The main objective for development of the HeliPS is to carry out studies on ion-ion plasmas in electronegative gases. In the near future, ion-ion plasmas will be formed in electronegative gases in the downstream of the plasma production region. Although the system is primarily designed to carry out ion-ion plasma experiments, the same system can also be used for experimental studies on some basic helicon plasma properties such as wave propagation, wave coupling, and plasma instability. At present, argon plasma is produced with a RF power supply of 13.56 MHz frequency. External circuit parameters, such as antenna current, plasma resistance (Rp), and internal parameters, such as electron density and temperature, are measured. The details of the experimental setup development, device characteristic, as well as preliminary plasma production and characterization to confirm occurrence of the helicon plasma in the system are presented in this article.

Plasma characterization of a microwave discharge ion source with mirror magnetic field configuration.

Microwave coupling to plasma through cavity dependent resonant modes is one of the key aspects in a microwave discharge ion source (MDIS) for improving the ion beam qualities as well as plasma dynamics. Knowing these concerns, a MDIS is designed, fabricated, and developed at Institute for Plasma Research to produce high current and a low emittance ion beam for accelerator applications. The present manuscript reports the development of MDIS and the characterization results of the first plasma produced by launching a microwave (MW) of frequency 2.45 GHz. The plasma is characterized at a particular distance away from the ion extraction aperture, using three diagnostics tools such as a Langmuir Probe (LP), Optical Emission Spectroscopy (OES), and a microwave spectrum analyzer. The required mirror-B magnetic field is created by placing four high power ring magnets (each magnet pole strength is 1.38 T) around the cylindrical source chamber. All diagnostics measurements are performed under an operating pressure of range 2 × 10-4-1 × 10-3 mbar and the plasma absorbed power of 30-160 W. The measured cold electron temperature and density varies in the range of ∼1.5-11.8 eV and 5.6 × 1016 m-3-6 × 1017 m-3, respectively, within the source volume. The electron population has distinct hot and cold plasma temperature. The hot electron temperature changes from ∼20 to 70 eV within the above absorbed power range. The LP and OES measurements witnessed the density jumps from under-dense (∼7.3 × 1016 m-3) to over-dense (∼2.9 × 1017 m-3) for the change in absorbed power from 50 W to 80 W. This density jump is accompanied by the sideband generation around the cavity resonant mode (including the launched MW) frequencies which range from 238 kHz to 873 kHz and is recognized as ion waves from the dispersion relation. The ion temperature, estimated from these observed low frequency instabilities, changes from 0.095 to 1.25 eV. The influences of these instabilities on beam emittance growth are of paramount importance in future studies.

Performance evaluation of a permanent ring magnet based helicon plasma source for negative ion source research.

Helicon wave heated plasmas are much more efficient in terms of ionization per unit power consumed. A permanent magnet based compact helicon wave heated plasma source is developed in the Institute for Plasma Research, after carefully optimizing the geometry, the frequency of the RF power, and the magnetic field conditions. The HELicon Experiment for Negative ion-I source is the single driver helicon plasma source that is being studied for the development of a large sized, multi-driver negative hydrogen ion source. In this paper, the details about the single driver machine and the results from the characterization of the device are presented. A parametric study at different pressures and magnetic field values using a 13.56 MHz RF source has been carried out in argon plasma, as an initial step towards source characterization. A theoretical model is also presented for the particle and power balance in the plasma. The ambipolar diffusion process taking place in a magnetized helicon plasma is also discussed.

Development of a novel surface assisted volume negative hydrogen ion source.

H- ion based neutral beam injector is a critical heating and current drive system in a fusion reactor. However, the present H- ion source configuration has limitations in terms of production, extraction, cesium (Cs) inventory and management. To overcome these limitations, a proof-of-principle experiment based on a novel concept regarding surface assisted volume H- ions production by sprinkling Cs coated tungsten (W) dust grains (low work function surface) into a hydrogen plasma is carried out. Four different diagnostics have been used to validate the concept. The H- ion fraction is estimated from (a) Langmuir probe diagnostic, (b) phase velocity of ion acoustic waves, (c) dust current and confirmed by the measurement of (d) Balmer line ratio. The measured H- ion fraction with respect to the plasma density for different discharge conditions varies from ~0.2 to 0.3 in presence of Cs coated W dust particles. The experimental results show good agreement with the theoretical estimation.

Physics-electrical hybrid model for real time impedance matching and remote plasma characterization in RF plasma sources.

Plasma characterization and impedance matching are an integral part of any radio frequency (RF) based plasma source. In long pulse operation, particularly in high power operation where plasma load may vary due to different reasons (e.g. pressure and power), online tuning of impedance matching circuit and remote plasma density estimation are very useful. In some cases, due to remote interfaces, radio activation and, due to maintenance issues, power probes are not allowed to be incorporated in the ion source design for plasma characterization. Therefore, for characterization and impedance matching, more remote schemes are envisaged. Two such schemes by the same authors are suggested in these regards, which are based on air core transformer model of inductive coupled plasma (ICP) [M. Bandyopadhyay et al., Nucl. Fusion 55, 033017 (2015); D. Sudhir et al., Rev. Sci. Instrum. 85, 013510 (2014)]. However, the influence of the RF field interaction with the plasma to determine its impedance, a physics code HELIC [D. Arnush, Phys. Plasmas 7, 3042 (2000)] is coupled with the transformer model. This model can be useful for both types of RF sources, i.e., ICP and helicon sources.

Overview of ion source characterization diagnostics in INTF.

INdian Test Facility (INTF) is envisaged to characterize ITER diagnostic neutral beam system and to establish the functionality of its eight inductively coupled RF plasma driver based negative hydrogen ion source and its beamline components. The beam quality mainly depends on the ion source performance and therefore, its diagnostics plays an important role for its safe and optimized operation. A number of diagnostics are planned in INTF to characterize the ion source performance. Negative ions and its cesium contents in the source will be monitored by optical emission spectroscopy (OES) and cavity ring down spectroscopy. Plasma near the extraction region will be studied using standard electrostatic probes. The beam divergence and negative ion stripping losses are planned to be measured using Doppler shift spectroscopy. During initial phase of ion beam characterization, carbon fiber composite based infrared imaging diagnostics will be used. Safe operation of the beam will be ensured by using standard thermocouples and electrical voltage-current measurement sensors. A novel concept, based on plasma density dependent plasma impedance measurement using RF electrical impedance matching parameters to characterize the RF driver plasma, will be tested in INTF and will be validated with OES data. The paper will discuss about the overview of the complete INTF diagnostics including its present status of procurement, experimentation, interface with mechanical systems in INTF, and integration with INTF data acquisition and control systems.

Online tuning of impedance matching circuit for long pulse inductively coupled plasma source operation--an alternate approach.

Impedance matching circuit between radio frequency (RF) generator and the plasma load, placed between them, determines the RF power transfer from RF generator to the plasma load. The impedance of plasma load depends on the plasma parameters through skin depth and plasma conductivity or resistivity. Therefore, for long pulse operation of inductively coupled plasmas, particularly for high power (∼100 kW or more) where plasma load condition may vary due to different reasons (e.g., pressure, power, and thermal), online tuning of impedance matching circuit is necessary through feedback. In fusion grade ion source operation, such online methodology through feedback is not present but offline remote tuning by adjusting the matching circuit capacitors and tuning the driving frequency of the RF generator between the ion source operation pulses is envisaged. The present model is an approach for remote impedance tuning methodology for long pulse operation and corresponding online impedance matching algorithm based on RF coil antenna current measurement or coil antenna calorimetric measurement may be useful in this regard.

Optimization of negative ion current in a compact microwave driven upper hybrid resonance multicusp plasma source.

Performance of a microwave driven upper hybrid resonance multicusp plasma source as a volume negative ion source is reported. Microwaves are directly launched into the plasma chamber predominantly in the TE(11) mode. The source is operated at different discharge conditions to obtain the optimized negative H(-) ion current which is ∼33 µA (0.26 mA∕cm(2)). Particle balance equations are solved to estimate the negative ion density, which is compared with the experimental results. Future prospects of the source are discussed.

Multiple delivery cesium oven system for negative ion sources.

Distribution of cesium in large negative ion beam sources to be operational in ITER, is presently based on the use of three or more cesium ovens, which operate simultaneously and are controlled remotely. However, use of multiple Cs ovens simultaneously is likely to pose difficulties in operation and maintenance of the ovens. An alternate method of Cs delivery, based on a single oven distribution system is proposed as one which could reduce the need of simultaneous operation of many ovens. A proof of principle experiment verifying the concept of a multinozzle distributor based Cs oven has been carried out at Institute for Plasma Research. It is also observed that the Cs flux is not controlled by Cs reservoir temperature after few hours of operation but by the temperature of the distributor which starts behaving as a Cs reservoir.

A study of obliquity of femoral shaft in Eastern Indian population.

In the erect posture, femur is not absolute vertical, being separated above from its fellow by a considerable interval, which corresponds to the breadth of the pelvis, and inclines gradually medially and downward, so as to approach its fellow, for the purpose of bringing the knee joints near the line of gravity of the body. In the present study obliquity of femoral shaft measured in 127 dry femora. Mean obliquity of femoral shaft for 62 left sided femora found 8.431 degrees with standard deviation of 2.361 degrees whereas for 65 right sided femora were found to be 7.708 degrees with standard deviation of 2.425 degrees. When total 127 femora considered, mean bicondylar angle of 8.061 +/- 2.412 degrees was obtained. Though statistically insignificant, mean bicondylar angle determined on left side was higher than that on the right side.

True palmar pattern in vitiligo--a case control study.

Characteristic epidermal ridges formed on the finger pad and on the palm by the end of the second trimester and remain unchanged thereafter and those are responsible for the highly specific finger prints of each individual. These ridges are nither influenced by later prenatal period nor they subject to any influence in the postnatal environmental factors because the formation of ridge patterns gets already completed by about the eighteenth week of gestation. Dermatoglyphics is a scientific study of such epidermal ridges. Dermatoglyphic study of both palms of clinically diagnosed vitiligo patients and control subjects were carried out and statisticaltly analysed in respect to sex and side of hands. The study revealed variable number of deviations of this patterns in Vitiligo patients when compared with that of control. Increased number of true palmar patterns in right hypothenar, right thenar and both inter digital areas 2 (ID-2) and decreased TPP in Rt. ID3, Rt. ID4 in vitiligo male patients and increased TPP in Rt. Hypothenar and Rt. ID1 and decreased TPP in Rt. ID2 and Lt. ID 3 in vitiligo female patients while compared with that of the control group. Some of the variations observed were stastically significant.

Prospective study of application of biological communication (cybernatics) in management of chronic low back pain--a preliminary report.

To observe the effects of application of cybernetics (theories of communication). This is an open level prospective study, involving patients with chronic low back pain of more than 3 months. Assessment were done before the start of therapy and after the completion of therapy every day for consecutive 6 days of treatment protocol. A total of 8 patients were enrolled (4 male, 4 female). The Visual Analogue Scale (VAS) was used to assess pain, Oswestry Disability Scale (ODI) was applied for scoring disability. ODI was scored at the start of treatment on 1st day and at the end of the treatment on 6th day. Mean VAS reduced from 8.12 to 6.93 after 1st day, which was also statistically significant (p < .01) .This trend continued and there was very significant reduction (p < .001) of VAS in the end when means were compared with pretreatment value. Mean Oswestry disability index reduced from 49.875 to 18.44 at the end of treatment which was statistically very significant (p < 0.001). There were significant improvements in all the outcome measured after Scrambler therapy.

Prevalence and causes of low birth weight in India.

INTRODUCTION: The aims of the study are (i) to understand inter-zone and interstate variation of low birth weight (LBW) and (ii) to determine the key variables to reduce LBW in India. METHODS: Using the latest National Family Health Survey (NFHS) data of 2005-06 which showed the percentage distribution of LBW infants, ANOVA and post-hoc test were performed to determine the spatial variation of birth weight. The covariates which influence LBW fell into three categories: (i) social variables which included location, mother's education, religion, access of mothers to newspapers, television and family structure; (ii) economic variable namely, the wealth index, and (iii) biological variables which consisted of sex of the children, birth order, and mother's body mass index (BMI). Three models of Logistic regression were carried out to examine the influence of the combinations of these direct and indirect factors. RESULTS: In India, nearly 20% of new borns have LBW. Males have less frequency of LBW than females. The North-east zone has the lowest prevalence of LBW while the north zone has the highest. Mother's education, access to TV and nuclear family, and intake of iron tablets are the most important socio-economic influences on the determination of birth weight in India. CONCLUSION: It is essential to provide proper diet and nutritional care of mothers during pregnancy. Increased education of mothers through programmes in TV and newspapers articles have significant roles to play in reducing LBW in India.

Vessels in femoral triangle in a rare relationship.

The femoral region of the thigh is utilised for various clinical procedures, both open and closed, particularly in respect to arterial and venous cannulations. A rare vascular pattern was observed during the dissection of the femoral region on both sides of the intact formaldehyde-preserved cadaver of a 42-year-old Indian man from West Bengal. The relationships and patterns found were contrary to the belief that the femoral vein is always medial to the artery, just below the inguinal ligament and the common femoral artery. The femoral artery crossed the vein just deep to the inguinal ligament so that the femoral vein was lying deep to the artery at the base of the femoral triangle. Just deep to the inguinal ligament, the profunda femoris artery (deep femoral artery) arose from the femoral artery, and the long saphenous vein drained into the femoral vein. The embryological and clinical correlations are discussed.

Median defect in the skull.

A median defect in the region of the root of the nose, in between the two orbits, was discovered in the dried skull of a 44-year-old female cadaver, during routine undergraduate teaching. The two small nasal bones articulated with each other and the cribriform plate of the ethmoid. The lacrimal bones and frontal processes of the maxillary bones were also deformed. We propose that the median defect was due to abnormality at the fonticulus frontalis, the prenasal space and the interorbitonasal part of the nasal capsule, as well as defects in the ossification of the maxilla, lacrimal and frontal bones.