Breakthrough 4π helium ion energy spatial distribution determination in plasma focus space by Sohrabi mega-size panorama cylindrical ion image detector

doi:10.21203/rs.3.rs-4362896/v1

Download PDF

Article

Breakthrough 4π helium ion energy spatial distribution determination in plasma focus space by Sohrabi mega-size panorama cylindrical ion image detector

https://doi.org/10.21203/rs.3.rs-4362896/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

Recently Sohrabi theorized and discovered that ions in plasma focus devices (PFD) are emitted in 4π ion space instead of within small solid angle above anode, as commonly believed. Ion energies are commonly determined by others at single points above or around anode top. In this study, He ion energy distributions were determined in 4π PFD space applying Sohrabi mega-size panorama cylindrical polycarbonate ion image detectors pre-etched by surface layer removal (SLR) process before electrochemical etching. The SLR is pre-etching process which remove certain thickness of detector surface. Results show that track density versus layer thickness removed has saturation plateau corresponding to countable track density which is equal to penetration range of “minimum detected energy” in the detector. Also, thickness in which track density approaches zero is equal to penetration range of “maximum detected energy” in detector. At different cylindrical detector heights studied, corresponding minimum ion energies (7.0 to 328 keV) and maximum ion energies (70 to 640 keV) and for top cylinder base at different angles minimum energies (57 to 535 keV) and maximum energies (135 to 640 keV) were determined. The novel methods applied proved quite efficient for determination of He ion energies in 4π PFD ion space.

Physical sciences/Physics

Physical sciences/Physics/Applied physics

Polycarbonate cylindrical detectors

ion energy distribution

Surface layer removal process

electrochemical etching

plasma focus device

A plasma focus device (PFD) is a source of high-energy electrons, ions, x-rays and neutrons for applications such as radioisotope production^1,2, synthesis of nanophase materials^3,4, lithography⁵, thin film material processing⁶, ion implantation^1,7, radiography imaging⁸, and “Ionology Art for Art Ionology⁹”. Accordingly, safety and efficiency of PFD operation needs information on ion fluences and energies in PFD space¹⁰.

Extensive studies have been performed to characterize ion emission in PFDs in order to determine ion fluence, ion energies, ion emission distribution and energy spatial distribution. Such studies have been commonly by others at one point on or around the z-axis above the anode by applying ion detectors like activation detectors for deuterium and nitrogen ions^2,11, Faraday cups for hydrogen, helium, neon, argon and nitrogen ions^12–22, Thomson spectrometer for hydrogen, deuterium, helium and nitrogen ions^23–26, other methods used time of flight (TOF) technique for hydrogen and carbon^27,28, CR-39 for hydrogen, deuterium, neon and nitrogen^23,29–33, PM-355 for deuterium ions³², LR-115 for hydrogen ions³⁴ and polycarbonate detectors by using extra aluminum filter as attenuators for nitrogen³⁵.

Recently, a breakthrough 4π ion emission theory by Sohrabi led to discovery of ion emission in 4π PFD ion space^36,37. For this discovery, Sohrabi 3D panorama position sensitive mega-size cylindrical polycarbonate ion image detectors (MS-PCIDs) were used around the walls of a PFD for hydrogen, deuterium, helium, and nitrogen ion distribution which observed for the first time “ion cathode shadows” on the MS-PCIDs^36–40, In this discovery, “Two-sources Ion Emission Model” was also theorized accordingly based on which ions are emitted in 4π PFD ion space from “anode top” as an intense “point ion source” and “anode cathodes assembly” as a “line ion source^36,41”. Also, a third possible ion generating source was discovered in 4π PFD space by Sohrabi which is thought to be due to in-space ion generation⁴², yet to be further verified. In line with such studies, the effects of different PFD technical parameters on 4π ion emission were studied such as effects of anode geometry on forward wide-angle neon ion emissions and gas pressure on angular distribution of hydrogen ions^38,41.

Also, relative ion energy distributions in 4π PFD ion space have been directly observed by unaided eyes on MS-PCIDs during electrochemical etching (ECE) processing by a recently-invented panorama single-cell mega-size (MS-ECE) chamber system applying 50 Hz – HV field strength^40,43. The qualitative results also showed that higher-energy ions with low-fluence are on top of the anode axis and low-energy high-fluence ions are at radial distances from the anode axis with an angular distribution. However, there is still a crucial need to determine quantitatively ion energy ranges and distributions in 4π PFD ion space to better understand PFD mechanisms and to better use the ions for different applications.

To quantitatively identify ion energy ranges and distributions in 4π PFD ion space, an ion energy determination method was recently introduced and used in this study. This method has the ability to determine ion penetration range and energy for ions such as He ions, by applying a pre-etching surface layer removal process before ECE processing to small detectors cut from the area of the MS-PCID, called here "Surface Layer Removal” (SLR) process.

Having said the above, it is the purpose of this study is to:

Determine He ion energy ranges and distributions in a Mather-type 3.5 kJ PFD using Sohrabi panorama cylindrical MS-PCID by applying a new SLR process before an ECE process,
Develop and improve practical aspects of the SLR process for extensive ion energy distribution determination in 4π PFD ion space.
Characterize He ion energy spatial distribution along the z-axis on the cylindrical detector and its top cylinder base as well as angular ion energy distribution in 4π PFD ion space, and
Analyze the ion energy ranges and distributions in 4π PFD ion space in comparison with the methods commonly used at single points in limited PFD space.

A 3.5 kJ Mather-type plasma focus device (~ 12 kV, 40 µF, and 115 nH) was used in this study with technical specifications as follow:

cylindrical upright geometry with 26 cm inner diameter, 38 cm inner height and 81 cm inner circumference;
central “anode cathodes arrays assembly” with a flat-end cone type solid copper anode (2 cm diameter, 14.8 cm length) and six copper cathodes (0.9 cm diameter, 13 cm length) placed at 4.5 cm distance from the anode; all inserted on a circular base of 1 cm thickness and 14.5 cm diameter; and
with 5.5 cm length Pyrex glass tube as the insulator sleeve.

The flat-end cone anode type provides high He ion fluences in 4π PFD ion space compared to other anode types studied³⁸. In order to determine He ion energy distribution in 4π PFD ion space, panoramic cylindrical MS-PCID (500 µm thick) (circular detector 26 cm in diameter top base, 21 cm from the anode top and a rectangular detector (38 cm × 81 cm) installed on the inner cylindrical wall of the PFD. Subsequently, the PFD was filled with He gas at approximately ~ 7.5 mbar pressure and fired for only one single pinch, unlike other studies which apply many pinches. Schematic diagram of the PFD and MS-PCIDs placed inside the PFD is shown in Fig. 1a,b,c.

The panorama cylindrical MS-PCID is then exposed to He ions in 4π PFD ion space emitted under only a single pinch, followed by SLR and ECE processes in order to determine He ion energy distributions, as described in four main steps below to:

Locate the so-called “ion cathode shadows”³⁶ and areas with negligible ion fluence in 4π PFD ion space. This step is of importance since He ion energy is measured in ion saturated areas with high enough ion fluence;
Cut the circular and rectangular MS-PCID respectively into small pieces; 6 concentric circular stripe polycarbonate track detectors (PCTDs) for the top cylinder base and 10 stripe PCTDs on the wall cylinder detector along the z-axis. Then, each PCTD was further cut into smaller 2.0 cm × 2.0 cm pieces for 6 concentric circular stripe PCTDs and 3.1 cm × 3.8 cm pieces for 10 stripe PCTDs.
Obtain an optimum pre-etching rate for step-by-step SLR process to determine the highest thickness layers removed from small PCTD surface; and
Determine He ion energy distribution by applying SLR process followed by ECE process of small PCTDs and shifting them between the two processes within the ECE chamber. This ensures the study of ion energy within saturated areas in the 4π PFD ion space.

Step one: Locate ion cathode shadows in rectangular MS-PCID

It has been proved that for the PFD used with six cathodes, 6 ion cathode shadows have been formed on rectangular MS-PCID installed on PFD wall which has been exposed to He ions emitted under only a single pinch and processed by single-cell MS-ECE chamber (Fig. 2a). Ion cathode shadow have ~ 12 cm length and ~ 2.6 cm width with 13 cm distance from each other³⁶. A new long ECE chamber recently invented by Sohrabi (not yet published) was applied to stripe PCTDs to find a section of an ion cathode shadow. This chamber has ability to process stripe PCTDs with constant width of 3.6 cm and variable length of 12 cm to 81 cm. A small stripe PCTD (3.6 cm × 12 cm) cut from the rectangular MS-PCID (6 cm distance from PFD base) was processed using the long ECE chamber, as shown in Fig. 2.

As can be seen in Fig. 2b, a section of an ion cathode shadow after ECE process is observed as dark region with unaided eyes. The areas under 6 ion cathode shadows were not included in the He ion energy distribution determination due to having negligible ion fluence.

Step two: Cutting rectangular and circular MS-PCID into small PCTDs

The qualitative study of hydrogen ion energy distribution in PFD shows a variation of ion energy along the z-axis on the cylindrical wall of PFD and also by varying the angle from the anode axis on top PFD base⁴⁰. The same variations were assumed also for He ion energy distribution to verify this assumption. Accordingly, the circular MS-PCID was cut into 6 concentric circular rings by considering angle from the anode tope axis including 0^o, 6^o, 12^o, 18^o, 24^o and 30^o. Then, each circular stripe PCTD was cut into small PCTDs with 2 cm × 2 cm area. Also, the rectangular MS-PCID were cut into 10 stripe PCTDs along the z-axis and then each one was cut into 26 small PCTDs of 3.1 cm × 3.8 cm as shown in Fig. 3a,b. He ion energy and its distribution was performed on these small PCTDs by applying SLR and ECE processes. The areas of the ion cathode shadow and the area cut for locating the shadows before ECE process were eliminated from the He ion energy study due to negligible ion fluence as expected (white areas in Fig. 3b).

Step three: Determining the optimum pre-etching rate in SLR process

A SLR process was applied to determine He ion energy distribution through which penetration range of ions registered on PCTDs is determined and the corresponding energy was estimated by SRIM software^44,45. The SLR process applies a chemical pre-etching process by a concentration of ethylenediamine (ETD) solution to remove a layer of a certain thickness from an exposed PCTD surface before ECE process. This method was validated for alpha particles of various energies at a constant fluence. It is proved that the registrable energy range of PCTD alters by varying the layer removal thickness, so that the upper limit of the energy range can be determined in He ion field in 4π PFD space. The SLR process was applied in another study to obtain different thickness removal rates by applying different ETD concentrations (article under publication process in another Journal), However, for this study for determining an optimum ETD concentration for precise layer removal rate, first ETD solution of 70% concentration was used to estimate the highest thickness layer removed from the small PCTD surfaces leading to 0.3 µm/min thickness removal rate. This preliminary concentration (70% ETD) was applied on 18 randomly selected small PCTDs (3.1 cm × 3.8 cm) cut from rectangular MS-PCID to remove thickness of 1, 2, 3, 4, 5 and 6 µm from each small PCTD surface. Then, the small PCTDs were processed in the triplet ECE chamber applying 50 Hz − 2 kV with PEW at 26 ± 1°C for 6 h⁴⁶. The analysis of He ion tracks on small PCTDs after applying SLR and ECE processes, as observed under a Vikon light microscope, shows that He ion tracks are washed out after 3 µm layer removal. Consequently, an ETD solution with concentration of 50% (with slower thickness removal rate 0.01 µm/min) is used to remove Different thicknesses ranging from 0.1 to 3 µm from small PCTD surface in 0.1 µm steps by applying appropriate pre-etching duration. Then, after applying the ECE process and by further washing and drying, track density of each small PCTDs was determined.

Step four: Applying SLR and ECE processes to small PCTDs for energy determination

Although the regions with low ion fluences like as ion cathode shadows were determined and ignored in energy distribution determination in step 2, a further assurance was obtained by a special way of processing of each small PCTD as shown in Fig. 4a,b,c. The SLR process was first performed on each small PCTD. Then, the ECE process was applied to each small PCTD by slightly shifting them within the triplet ECE chamber, where the effective etch areas of these two processes overlap by approximately 90%, as shown in Fig. 4a. After applying these two processes, three distinct regions were formed on each small PCTD. Region (I) represents 10% of the effective ECE etched area, where He ion tracks were formed only by the ECE process, resulting in narrow crescents on each small PCTD, region (II) covers 90% of the effective ECE etched area, where He ion tracks were formed by both SLR process and the ECE process. region (III) zero tracks formed, as this area was only processed by SLR process. In other words, the narrow crescents observed on each small PCTD are considered a reference to qualitatively compare the changes in He ion track density registered with and without applying SLR process before ECE processing on small PCTDs, as shown in Fig. 4b. Also, this method ensures that He ion energy determination is performed on small PCTDs with ion saturation in narrow crescent area, excluding those where ion track density is not saturated.

The data of extensive measurements on He ions energy distribution in 4π PFD ion space is presented including the overall observation on He ions registered on MS-PCIDs and data on He energy range detected and also spatial distribution of He ion energy on cylindrical MS-PCID obtained after SLR and ECE processes.

As stated in material and method section, the He ion energy determination was performed in areas of high enough fluence by defining a reference area like a narrow crescent on each small PCTD. Small PCTDs were selected where detector response reached saturation due to He ion tracks within this narrow crescent area. It has been proved that alpha track density registered on PCTDs is linear up to an upper detection limit of ~ 3.0 × 10⁶ alpha.cm^− 2 at all energies⁴⁷. Beyond this threshold, the detector response becomes saturated with increasing alpha fluence. Consequently, in areas where the detector response is saturated, the He ion fluence exceeds 3.0 × 10⁶ ion.cm^− 2. This saturation response is visible by unaided eyes on the narrow crescent of each small PCTD as processed just by ECE, allowing for qualitative comparison of the He ion fluence registered on small PCTDs with and without applying SLR process.

Table 1 shows direct photography of narrow crescent detector area with SLR and ECE-processed area of small PCTDs by a normal scanner and their microphotographs (40x magnification) at the margins of these two areas of small PCTDs at a height of 31 cm on the cylinder detector wall from the PFD base, as an example. The thickness of layer removed from small PCTD surfaces is shown under each image in the table. Some main (overall) observations from Table 1 are as follow:

The saturation (high-density) area is observed as white on all images with observed by unaided eyes (Table 1a). The intensity of the white color is reduced by increasing the thickness of layer removed from small PCTDs showing gradual wash out of ion tracks with low-energy. The areas with no He ion track density is observed in black.
The reference area of narrow crescent is white on all different thicknesses removed (Table 1a). This observation confirms that He ion energy determination is performed on areas with high enough He ion fluence.
The small PCTD saturation disappears after removing a certain thickness from small PCTD surface which is equal to the penetration range of the low-energy ions registered with high-track intensity on small PCTDs (Table 1b, 0.5 µm). The corresponding energy of this penetration range is called hereafter as “minimum detected energy” which is the upper energy limit of most probable ions registered on small PCTDs. In other words, the tracks of low-energy ions that saturated on the small PCTD are washed out during pre-etching process up to the “minimum detected energy” after which He ion track density can be counted and analyzed.
No track density is observed after removing a certain thickness that is equal to the penetration range of the He ions registered with maximum energy on the small PCTDs hereafter called “maximum detected energy” (Table 1b, 1.3 µm).
The intensity of the He ion tracks decreases with increasing layer thickness removed. However, this reduction from 0.2 to 0.5 µm is qualitatively evident and cannot be quantified due to PCTD saturation caused by the high fluence of low-energy ions (Table 1b).

Figure 5 shows ion track density versus layer thickness removed from small PCTD surfaces; small PCTDs were cut from cylindrical MS-PCID exposed to He ions in 4π PFD space at different heights from the PFD base on the inner cylindrical wall, and at different angles from the anode axis on the top PFD base. The main conclusions obtained from Fig. 5 follow:

The same trend is observed for all graphs, i.e. a plateau followed by an almost sharp fall of track density by increasing the layer thickness removed. The plateau is corresponding to the PCTD saturation caused by the high fluence of low-energy ions. Although the intensity of the He ion fluence decreases by increasing the layer thickness removed, such reduction is not countable in the plateau region. The layer removal thickness in which the plateau ends is equal to penetration range of minimum detected energy described above. Also, the decreasing trend of track density after plateau is related to a step-by-step reduction of the He ion fluences with lower energies. Finally, the track density reaches zero value that is equal to the penetration range of maximum detected energy described above.
For the height of 7 cm, no plateau is observed showing that the ion fluences are not high enough to saturate the PCTD probably due to ion cathode shadow effects. However, a decreasing trend is observed by increasing the layer thickness removed from the PCTDs.
The energy of He ions registered on the PCTDs increases by increasing the layer thickness removed. Since the high energy He ions have a higher penetration range in PCTDs which are detectable by SLR process as described in details elsewhere (article under publication process in another Journal).

The accuracy of He ion energy distribution in different heights from the PFD base was investigated by applying SLR process on all 26 small PCTDs cut from MS-PCID at each height. The results show no change in He ions energy distribution at each height, i.e. He ions have the same energy regardless of their angular position on the cylindrical wall of PFD. Also, the He ions energy distribution on the anode top depends only the angle from the anode axis and no variation was observed on each concentric ring, i.e. radial direction from the anode axis, as predicted previously qualitatively⁴⁰.

The minimum and maximum He ions energies on the inner cylindrical wall of the PFD obtained for different cylinder heights from the PFD base and different angles from the anode axis on top PFD base are presented respectively in Tables 2 and 3. The lowest energy detected range is 7.0 to 70 keV for the cylinder height of 37 cm and the highest He ion energy range is 380 to 640 keV for the cylinder height of 6.9 cm. On the other hand, the lowest energy range is 57 to 135 keV on the angle of 30° from the anode axis and highest He ion energy range from 535 to 640 keV on the anode top center, i.e. 0° from the anode axis on top PFD base. Also, Fig. 6a,b shows the minimum detected energy and maximum detected energy distributions in 4π PFD ion space according to the cylinder height from the PFD base and angle from the anode axis on top PFD base. As can be seen, the minimum and maximum detected energy decrease by increasing the cylinder height from the PFD base and by increasing the angle from the anode axis on top PFD base.

Table 2

The minimum and maximum He ions energies obtained for different cylinder heights from the PFD base using rectangular MS-PCID installed on the inner cylindrical wall of the PFD.
Height (cm)	Detected Energy (keV)
Distance from the PFD Base	Minimum	Maximum
37.00	7	70
34.50	15	117
31.05	45	213
27.60	85	378
24.15	135	405
20.70	192	455
17.25	257	535
10.35	304	600
6.90	380	640

Table 3

The minimum and maximum He ions energies obtained for different angles from the anode axis using circular MS-PCID installed on top PFD base.
Angle (degree)	Detected Energy (keV)
from Anode Axis	Minimum	Maximum
30°	57	135
24°	135	213
18°	236	328
12°	304	430
6°	430	565
0°	535	640

The 3D distribution of the maximum detected energy as well as the extended graphs of 2D energy distribution for the cylindrical MS-PCID are shown in Fig. 7a,b,c. The change in color on the graphs indicates variations in the energy distribution at different points. For example, the constant energy of the He ions is simply observed at Y-axis (circumference of the cylindrical MS-PCID) and decreasing trend of the He ions energy is also observed along the Z-axis (different height from the PFD base) (Fig. 7b). Also, a “U-shaped curve” of the energy distribution for the circular MS-PCID on the anode top simply shows the maximum energy observed at the center as a peak and a decreasing of the energy on both site by increasing the radial distance from the center (Fig. 7a). This graph simply provides a visual representation of how the He ions energy is distributed across the 4π PFD ion space which is of importance in applications involving ion energy information.

Having insights on spatial ion energy distribution in 4π PFD space is of high importance in understanding ion acceleration during the PFD pinch process and 4π ion applications. The discovery of 4π ion emission in PFD space by Sohrabi^{36,37,40–42}, required having in-depth information on determination 4π ion energy spatial distribution. Therefore, this study was focused on a breakthrough methods for determination of helium ion energy distribution in 4π PFD space by applying a surface layer removal of mega-size cylindrical ion image detector. In this method, the SLR process was applied on areas of cylindrical MS-PCID installed on the inner walls of a Mather-type 3.5 kJ PFD. The results provided information on relationship between ion fluence and ion energy in 4π PFD ion space, He ion energy range and spatial ion energy distribution in 4π PFD ion space are discussed as described further in detail below.

Relationship between ion fluence and ion energy in 4π PFD ion space

The plateaus observed in Fig. 5 for different cylinder heights from PFD base (except at height of 7 cm) and also different angles from anode axis shows that the low-energy He ions are produced with higher fluences in 4π PFD ion space. Also, at a certain height and a certain radial distance from the anode axis, He ion fluences decrease, and He ion energies shift to the higher energies. This observation confirms our pervious study in which the lower track density and higher ion energy was reported at the center of circular MS-PCID for hydrogen ions⁴⁰. The same trend was also observed in other studies in which low-energy hydrogen and He ions contribute to high fluences as studied for limited points in PFD space^20,27.

He ion energy range in 4π PFD ion space

The minimum and maximum He ions energy are reported for each location in the 4π PFD ion space as summarized in Tables 2 and 3. The first interesting result obtained is that He ions with a relatively wide range of energy are emitted in a single pinch in 4π PFD ion space from minimum 7.0 keV (at 37 cm height from the PFD base) to maximum 640 keV (at the center of circular MS-PCID located 21 cm from the anode top). Also, the locations with high energy He ions is reported to be the center of anode top and height of 7 cm from the PFD. The locations with low energy He ions are 30° from anode axis at a height of 37 cm from the PFD base.

Spatial distributions of He ion energies in 4π PFD space

The “minimum detected energy” determined is constant at each height on the rectangular MS-PCID (installed on PFD cylindrical wall) and decreases by increasing the height from the PFD base. On the other hand, the “minimum detected energy” has a decreasing trend by increasing the angle from the anode axis on top PFD base. The “maximum detected energy” has the same trend as “minimum detected energy” for different heights from the PFD base and different angles from the anode axis.

The combined information on He ion fluence, energy range and spatial distribution is of importance for applications in which a sample need to be irradiated at a special point in PFD space; e.g. for studying destructive effects of He ions on materials such as tungsten, which is used in nuclear fusion reactors¹⁰. In such applications, a group of samples can be placed for example at the same height from the PFD base around the inner circumference or at the same radial distance from the anode axis to be irradiated by He ions with a relatively same energy range. By this sample arrangement, uncertainties and complexities observed in other methods may be reduced.

Obviously, the ion energy range obtained in PFD depends on different parameters such as ion type, anode geometry, gas pressure, energy of the bank and location of ion energy measurement inside the PFD. The energy ranges of He ions, obtained from limited points in other studies and from 4π space in this study are summarized in Table 4. As can be seen, the active detection methods applied like Thomson analyzer method are able to determine ion energies at limited points due to complex experimental set up, time and cost considerations and also difficulty in analysis of the data obtained. However, the method applied in this study, i.e. applying SLR process on areas of cylindrical MS-PCID before ECE processing has some advantages including:

The Sohrabi cylindrical MS-PCID can register He ions in 4π PFD space only under one effective single PFD pinch while the other methods like Faraday cup method needs usually large numbers of pinches to be able to provide precise energy data in a single point.
The cylindrical MS-PCID followed by SLR process can determine He ion energy in 4π PFD space that can provide a 3D spatial distribution of ions energy and in turn can extend the application of PFD. While the other methods applied so far have provided ions energy data in a single and discrete points in the PFD space by a well-collimated ion beam emitted from PFD.
The cylindrical MS-PCID can be applied in different sizes according to the PFD size requirement and can be inserted in PFD space with different sizes simply without any setup complexity or damage to the detector itself.
The environment conditions presented in PFD space such as temperature, humidity, mechanical shocks and electromagnetic noise has no effect on the cylindrical MS-PCID ion registration and response while the active methods are affected by such variations making uncertainties in their responses.

Table 4

He ion energy ranges obtained in different studies
Reference	PFD Gas Pressure / Energy of the Bank	Detection Method / Location Measurement	He Ion Energy Range
This study	7.5 mbar / 3.5 kJ	Sohrabi cylindrical MS-PCID with 1 pinch / at 4π ion space	7.0-640 keV
El-Aragi 2014¹⁹	1.1 mbar / 112.5 J	Faraday cup / at a single point above anode top	0.3–540 keV
Seyyedhabashy 2020²⁴	1.1 mbar / 2.7 kJ	Thomson spectrometer with 20 pinches / at a single point above anode top	10–200 keV
Sharma 2021²⁰	2.0 mbar / 3.0 kJ	Faraday cup with 20 pinches / At a single point above anode top	100–800 keV

The spatial distribution of He ions energy and energy range in 4π PFD ion space were determined for the first time in this study. The Sohrabi panorama cylindrical MS-PCID was installed on the walls of the PFD to register He ion fluence and energy by applying SLR pre-etching process to remove a certain thickness from the PCTD surface. The spatial distribution of He ions energy on the cylindrical MS-PCID shows higher energy He ions at lower heights from the cylinder base with a constant energy range all around the circumference of the cylindrical MS-PCID. Also, spatial distribution of He ions energy on the anode top shows higher energy ions at the center with no change in energy range for each radial distance from the anode axis. For different cylinder heights, corresponding minimum ion energies were 7.0 to 328 keV and maximum ion energies were 70 to 640 keV. On the other hand, for top cylinder base at different angles minimum energies were 57 to 535 keV and maximum energies were 135 to 640 keV. The characterized He ions energies obtained in this study can extend the PFD applications involving a need for ion energy at different PFD location. Last but not least, the cylindrical MS-PCID and applying SLR process was proved for comprehensive coverage of ion registration and in turn ion energy spatial distribution determination in 4π PFD ion space.

Data Availability Statement

All data generated or analyzed during this study are included in this published article.

Acknowledgement

The research was carried out under the current budget of the Amirkabir University of Technology and there is no conflict of interest.

Authors Contribution

M.S., 1^st Ph.D. advisor, originated the idea, invented the “panorama cylindrical MS-PCID, planned and directly supervised the experiments; analyzed and interpreted the data and wrote the final submitted paper together with A.Z.; A.Z. exposed the MS-PCID, applied the SRL and ECE processes; obtained raw data, made extensive literature research, made the graphs and wrote the first draft of the paper in close cooperation and direct supervision of M.M.; R.A. (2^nd advisor), and M.H. supported the He ion beam irradiation in the PFD.

Angeli, E. et al. Preliminary results on the production of short-lived radioisotopes with a plasma focus device. Appl. Radiat. Isot. 63(5–6), 545–551 (2005).
Roshan, M., Rawat, R. S., Talebitaher, A., Lee, P. & Springham, S. V. Neutron and high energy deuteron anisotropy investigations in plasma focus device. Phys. Plasmas 16(5), (2009).
Soto, L. New trends and future perspectives on plasma focus research. Plasma Phys. Control. Fusion 47(5A), A361 (2005).
Rawat, R. High-energy-density pinch plasma: A unique nonconventional tool for plasma nanotechnology. IEEE Trans. Plasma Sci. 41(4), 701–715 (2013).
Kato, Y. & Be, S. Generation of soft x rays using a rare gas-hydrogen plasma focus and its application to x‐ray lithography. Appl. Phys. Lett. 48(11), 686–688 (1986).
Rawat, R., Chew, W., Lee, P., White, T. & Lee, S. Deposition of titanium nitride thin films on stainless steel—AISI 304 substrates using a plasma focus device. Surf. Coat. Technol. 173(2–3), 276–284 (2003).
Wang, Z., Yousefi, H., Nishino, Y., Ito, H. & Masugata, K. Fabrication of DLC films by pulsed ion beam ablation in a dense plasma focus device. Phys. Lett. A A 373(45), 4169–4173 (2009).
Hussain, S., Shafiq, M., Ahmad, R., Waheed, A. & Zakaullah, M. Plasma focus as a possible x-ray source for radiography. Plasma Sources Sci. Technol. 14(1), 61 (2005).
Sohrabi, M. & Zarrinshad, A. Novel “Ionology Art for Art Ionology Methods” in 4π plasma focus device space: bridging art, science and technology. J. Cult. Herit. 43, 219–226 (2020).
Chen, H. Y. et al. The influence of different isochronal annealing temperature on helium ion irradiation damage of W-Nb composites. Fusion Eng. Des. 159, 111857 (2020).
Kelly, H., Lepone, A. & Marquez, A. Nitrogen ion spectrum from a low energy plasma focus device. IEEE Trans. Plasma Sci. 25(3), 455–459 (1997).
Etaati, G., Amrollahi, R., Habibi, M. & Baghdadi, R. Angular distribution of argon ions and X-ray emissions in the APF plasma focus device. J. Fusion Energy 30, 121–125 (2011).
Mohanty, S. R. et al. Effect of anode designs on ion emission characteristics of a plasma focus device. Jpn. J. Appl. Phys. 46(5R), 3039 (2007).
Namini, S. E. et al. Ion beam emission in a low energy plasma focus device. J. Fusion Energy 29, 471–475 (2010).
Habibi, M. Angular distribution of ion beam emitted from a 3.5 kJ plasma focus device using different shapes of anodes. Phys. Lett. A 380(3), 439–443 (2016).
Etminan, M. & Aghamir, F. M. Angular distribution of ion beams energy and flux in a plasma focus device operated with argon gas. Vacuum 191, 110352 (2021).
Mohanty, S. R., Bhuyan, H., Neog, N. K., Rout, R. K. & Hotta, E. Development of multi Faraday cup assembly for ion beam measurements from a low energy plasma focus device. Jpn. J. Appl. Phys. 44(7R), 5199 (2005).
Farmanfarmaei, B., Yousefi, H., Salem, M. & Sari, A. Increasing ion and fusion yield in a dense plasma focus by combination of pre-ionization and heavy ion gas admixture. Phys. Plasmas 25(4), (2018).
El-Aragi, G. M. Detection of energetic particles from plasma focus using Faraday cup and SSNTD (LR-115A). Int. J. Phys. Sci. 9(20), 438–443 (2014).
Sharma, P. et al. High energy density pulsed argon plasma synthesized nanostructured tungsten for damage mitigation under fusion relevant energetic he ion irradiation. Appl. Surf. Sci. Adv. 6, 100172 (2021).
Moreno, J., Pedreros, J. & Soto, L. Alteration of miRNA profile as a result of intracranial self-stimulation. presented at international conferences. J. Phys. Conf. (2014).
Damideh, V. et al. Characteristics of Fast ion beam in Neon and Argon filled plasma focus correlated with Lee Model Code. Vacuum 169, 108916 (2019).
Ahmad, R., Hassan, M., Murtaza, G., Waheed, A. & Zakaullah, M. Study of lateral spread of ions emitted from 2.3 kJ plasma focus with hydrogen and nitrogen gases. J. Fusion Energy 21, 217–220 (2002).
mohammadreza Seyyedhabashy, M., Tafreshi, M. A., Shafiei, S. & Nasiri, A. Damage studies on irradiated tungsten by helium ions in a plasma focus device. Nucl. Eng. Technol. 52(4), 827–834 (2020).
Takao, K. et al. Characteristics of ion beams produced in a plasma focus device. Jpn. J. Appl. Phys. 40(2S), 1013 (2001).
Roshan, M. V., Yap, S. L. & Yap, S. S. Ion acceleration parameter of the plasma focus device. IEEE Trans. Plasma Sci. 49(4), 1340–1343 (2021).
Bhuyan, H., Chuaqui, H., Favre, M., Mitchell, I.& Wyndham, E. Ion beam emission in a low energy plasma focus device operating with methane. J. Phys. D: Appl. Phys. 38(8), 1164 (2005).
Raeisdana, A., Kiai, S. S., Sadighzadeh, A. & Rasouli, C. Measurement of ion energy by TOF detection technique in a dense plasma focus device. J. Fusion Energy 39(5), 292–296 (2020).
Ito, H., Kishimoto, R. & Ohashi, H. Angular distribution measurements of energy spectra of protons emitted from hydrogen plasma focus. presented at ICOPS/BEAMS 2014, (2014).
Bhuyan, M., Neog, N., Mohanty, S., Rao, C. & Raole, P. Temporal and spatial study of neon ion emission from a plasma focus device. Phys. Plasmas 18 (3) (2011).
Banjanac, R. et al. Flux and energy distribution of axial protons emitted from the hydrogen plasma focus. Radiat. Meas. 40(2–6), 483–485 (2005).
Kwiatkowski, R. et al. Measurements of electron and ion beams emitted from the PF-1000 device in the upstream and downstream direction. Nukleonika 56(2), 119–123 (2011).
Szydlowski, A. et al. Measurements of fast ions and neutrons emitted from PF-1000 plasma focus device. Vacuum 76(2–3), 357–360 (2004).
Antanasijević, R. et al. Angular distribution of protons emitted from the hydrogen plasma focus. Radiat. Meas. 36(1–6), 327–328 (2003).
Ghasemi, B., Rouhi, H., Davani, F. A. & Rad, Z. S. Energy and angular distributions of high-energy nitrogen ion of plasma focus device SBUMTPF1 by aluminum filters coated on polycarbonate nuclear track detector. J. Fusion Energy 32, 595–599 (2013).
Sohrabi, M., Zarinshad, A. & Habibi, M. Breakthrough in 4π ion emission mechanism understanding in plasma focus devices. Sci. Rep. 6(1), 38843 (2016).
Sohrabi, M. Breakthroughs in 4π panorama ionology in plasma focus devices for mechanisms understanding with special regards to hydrogen ions (protons). Radiat. Meas. 119, 192–198 (2018).
Sohrabi, M., Soltani, Z. & Sarlak, Z. Effects of anode geometry on forward wide-angle neon ion emissions in 3.5 kJ plasma focus device by novel mega-size panorama polycarbonate image detectors. J. Instrum. 13(03), P03011 (2018).
Soltani, Z., Sohrabi, M. & Habibi, M. Analysis of 3D deuterium ion emission angular distribution in plasma focus device using novel panorama polycarbonate detectors. Radiat. Phys. Chem. 165, 108404 (2019).
Sohrabi, M., Soltani, Z. & Habibi, M. Hydrogen ion emission studies in 4π plasma focus device space. Radiat. Phys. Chem. 172, 108836 (2020).
Sohrabi, M., Amrollahi, R. & Soltani, Z. Novel panorama “anode cathodes assembly” run-away hydrogen ion image studies in 4π plasma focus device space at different gas pressures. Radiat. Phys. Chem. 177, 109170 (2020).
Sohrabi, M. Discovery of third possible ion generating source in 4π plasma focus device space. Health Phys. 122(5), 614–617 (2022).
Sohrabi, M. Novel single-cell mega-size chambers for electrochemical etching of panorama position-sensitive polycarbonate ion image detectors. Rev. Sci. Instrum. 88(11) (2017).
Ziegler, J. Ion implantation Technology (1992).
Ziegler, J. & Manoyan, J. The stopping of ions in compounds. Nucl. Instrum. methods phys. Res. B 35(3–4), 215–228 (1988).
Sohrabi, M. A new triplet electrochemical etching (TECE) method. Radiat. Prot. Dosim. 48 (3), 279–283 (1993).
Sohrabi, M., Zarinshad, A. & Sarlak, Z. Alpha particle energy and fluence dependence of polycarbonate detectors. Radiat. Meas. 104, 8–12 (2017).

Table 1 is available in the Supplementary Files section.

No competing interests reported.

Table1.docx

Download PDF

Version 1

posted

You are reading this latest preprint version

Breakthrough 4π helium ion energy spatial distribution determination in plasma focus space by Sohrabi mega-size panorama cylindrical ion image detector

Status:

Version 1

Abstract

Figures

Introduction

Material and Method

Step one: Locate ion cathode shadows in rectangular MS-PCID

Step two: Cutting rectangular and circular MS-PCID into small PCTDs

Step three: Determining the optimum pre-etching rate in SLR process

Step four: Applying SLR and ECE processes to small PCTDs for energy determination

Results

Discussion

Conclusion

Declarations

References

Tables

Additional Declarations

Supplementary Files

Status:

Version 1