target foil

Top PDF target foil:

Characterization of proton and heavier ion acceleration in ultrahigh-intensity laser interactions with heated target foils

Characterization of proton and heavier ion acceleration in ultrahigh-intensity laser interactions with heated target foils

Proton acceleration from the front and rear surfaces of the Fe target foils was also diagnosed for the same heated and unheated shots by measuring 共 p , n 兲 reactions in 63 Cu. The proton energy spectra were deduced by convoluting the lit- erature cross section for the 63 Cu 共 p , n 兲 63 Zn reaction [ 15 ] and the SRIM-2003 calculated proton stopping ranges in Cu. The technique is described in detail elsewhere [7]. The deduced proton spectra are shown in Fig. 5, and have been corrected for the protons passing through the 1-mm-thick carbon sample ( Fig. 1 ) . The measurement was limited to protons with energy above ⬃ 13 MeV. As observed in previous ex- periments [7] the proton maximum cutoff energy is lower for the protons measured at the front side of the target. Signifi- cantly, the numbers of protons accelerated from both the front and rear surfaces of the heated target are reduced by about 2 orders of magnitude compared to the unheated target. The energy conversion efficiency to protons in this energy range is of the order of 2% for the unheated target, falling to ⬃ 0.01% for the heated target. The total energy conversion efficiency to protons ( over the full proton energy range ) from unheated targets under similar experimental conditions was measured to be about 7%.
Show more

6 Read more

Würl, Matthias
  

(2018):


	On the spectrometry of laser-accelerated particle bunches and laser-driven proton radiography.


Dissertation, LMU München: Fakultät für Physik

Würl, Matthias (2018): On the spectrometry of laser-accelerated particle bunches and laser-driven proton radiography. Dissertation, LMU München: Fakultät für Physik

To extract the absolute energy spectrum from the measured TOF signal current, a dedi- cated reconstruction method was developed. In contrast to TOF measurements of laser- accelerated ion bunches which had previously been published by other groups, the ap- proach presented within this thesis explicitly takes into account the temporal response function of the detection system. This is essential, as TOF differences of protons in the (near-)relativistic energy range are in the same time scale as the detector response. The approach was validated using an energy-modulated proton beam from a conven- tional electrostatic accelerator in the energy range up to 20 MeV and with ns-short proton bunches. Agreement between reconstructed energy distributions and the spectrum as ex- pected from Monte Carlo simulations and measurements using a magnetic spectrometer was found very promising. Measurements were also performed at LEX Photonics using laser-accelerated proton bunches from thin target foils. TOF signals were acquired for an unperturbated TNSA spectrum, as well as for a focused proton beam. Despite the dominant high frequency noise caused by the EMP, reasonable agreement was found be- tween the reconstructed spectrum using the TOF approach and measurements using the WASP or analytical calculations for an unfocused beam and for a beam focused by a pair of PMQs, respectively.
Show more

230 Read more

Intra-pulse transition between ion acceleration mechanisms in intense laser-foil interactions

Intra-pulse transition between ion acceleration mechanisms in intense laser-foil interactions

Multiple ion acceleration mechanisms can occur when an ultrathin foil is irradiated with an intense laser pulse, with the dominant mechanism changing over the course of the interaction. Measurement of the spatial-intensity distribution of the beam of energetic protons is used to investigate the transition from radiation pressure acceleration to transparency-driven processes. It is shown numerically that radiation pressure drives an increased expansion of the target ions within the spatial extent of the laser focal spot, which induces a radial deflection of relatively low energy sheath- accelerated protons to form an annular distribution. Through variation of the target foil thickness, the opening angle of the ring is shown to be correlated to the point in time transparency occurs during the interaction and is maximised when it occurs at the peak of the laser intensity profile. Corresponding experimental measurements of the ring size variation with target thickness exhibit the same trends and provide insight into the intra-pulse laser-plasma evolution.
Show more

13 Read more

EMP control and characterisation on high-power laser systems

EMP control and characterisation on high-power laser systems

energy, when more escaping electrons can be produced. Since the GHz component of the EMP is caused by a neutralization current propagating across the target stalk, by reducing the magnitude and duration of this current one may hope to limit the damaging effects of EMP. In this paper, we present new data that shows how a significant reduction in EMP can be achieved with minimal experimental disruption. Experimental results are divided into two main sections - one for EMP varia- tion with laser parameters and the other for variation with target foil and stalk/mount characteristics. The data presented here is independent of target thickness, of which more details can be found in the Appendix (see Section VII). All data used to produce the figures in this work, along with other supporting material, can be found at http://dx.doi.org/10.15124/a5d78c76-0546- 412c-8b02-9edcb75efbb7.
Show more

8 Read more

Learning to merge - language and vision: A deep evaluation of the encoder, the role of the two modalities, the role of the training task.

Learning to merge - language and vision: A deep evaluation of the encoder, the role of the two modalities, the role of the training task.

mantic similarity between the original word and the foil (computed as the cosine between the two corresponding word2vec embeddings Mikolov et al. (2013)); 2) frequency of original word in FOIL-COCO captions; 3) frequency of the foil word in FOIL-COCO captions; 4) length of the caption (number of words). The mixed-effect model was performed to get rid of possible effects due to ei- ther object supercategory (indoor, food, vehicle, etc.) or target::foil pair (e.g., zebra::giraffe, boat::airplane, etc.). For both LSTM + norm I and HieCoAtt, word2vec similarity, the frequency of the original word, and frequency of the foil word turned out to be highly reliable predictors of the model’s response. The higher the values of these variables, the more the models tend to provide the wrong output. That is, when the foil word (e.g. cat) is semantically very similar to the original one (e.g. dog), the models tend to wrongly classify the caption as ‘correct’. The same holds for frequency values. In particular, the higher the frequency of both the original word and the foil one, the more the models fail. This indicates that systems find it difficult to distinguish related concepts at the text-vision interface, and also that they may tend to be biased towards frequently occurring concepts, ‘seeing them everywhere’ even when they are not present in the image. Caption length turned out to be only a par- tially reliable predictor in the LSTM + norm I model, whereas it is a reliable predictor in HieCoAtt. In particular, the longer the caption, the harder for the model to spot that there is a foil word that makes the caption wrong.
Show more

140 Read more

Angle-dependent modulated spectral peaks of proton beams generated in ultrashort intense laser-solid interactions

Angle-dependent modulated spectral peaks of proton beams generated in ultrashort intense laser-solid interactions

The experiment was conducted on the Xtreme Light (XL) Ti: sapphire laser facility at the Institute of Physics, Chinese Academy of Sciences 16 . The schematic setup is shown in Fig 1. A p-polarized laser pulse of 100 fs pulse duration, 1~2.5 J energy and 800 nm central wavelength was focused using an f/1.67 off-axis parabola (OAP) mirror onto target foils at an incidence angle of 15 °. The laser energy on target after compression was from 1 to 2.5 J. The full width at half maximum (FWHM) of the laser focal spot was 8 μm, giving a maximum laser intensity of 5×10 19 W/cm 2 . The contrast ratio at 7 nanoseconds before
Show more

15 Read more

A study of the charged particles emitted from certain fast-neutron induced reactions

A study of the charged particles emitted from certain fast-neutron induced reactions

Data R e duction. After composite spectra had been formed for the whole energy range IMeV to löMeV, changes were made in the energy associated with each channel to allow for the ionization losses within the proportional counters and give the energy spectrum at the surface of the target foil. B e ­ cause the protons originated anywhere throughout the volume of the foil, a simple change in scale was not capable of correcting for these ionization losses. In the present work, considerable effort was expended to develop a computer programme which would reduce the experimental data, obtained using a target foil of finite thickness, to that spectra which would be observed if the foil caused no ionization losses. A programme for this data reduction was designed for the computer SILLIAC. Also included was a routine to convert the results to centre-of-mass coordinates and to lin­ earize the energy scales of the observed spectra. A flow diagram for this programme is presented in the Appendix.
Show more

155 Read more

Measurement of radioactivity and evaluation of activated nuclides due to secondary particles produced in stripper foil in J-PARC RCS

Measurement of radioactivity and evaluation of activated nuclides due to secondary particles produced in stripper foil in J-PARC RCS

Two methods to evaluate the secondary particles emitted by the foil are employed in our experiment. One is the direct measurement method to detect and identify each secondary particle, and the other is the radioactivity analysis method that uses several metal irradiation targets. In case of the first method, the development of radiation counters that can classify radiation as protons, neutrons, or gamma rays and analyse each energy level is vital. In case of the second method, it is important to select the target material and examine the radionuclides as indicators of secondary protons or neutrons in different energy ranges. Herein, we examine the radioactivity analysis method with PHITS code to search for radionuclides as indicators.
Show more

7 Read more

A parametric study on the accuracy of bending in micro W-bending using Taguchi method

A parametric study on the accuracy of bending in micro W-bending using Taguchi method

In this study, the output responses, namely the springback and negative springback angles, can be envisaged as a linear combination of the input parameters, i.e., foil thickness, foil orientation, grain size and punching frequency. Hence, a multiple-linear regression model using the least square method was employed to develop a mathematical model revealing the quantitative relationship between the parameters and corresponding response. The regression analysis was calculated using Minitab 17 based on the mean values of the springback and negative springback listed in Tables 3 and 4. Accordingly, the following regression equations for the springback and negative springback were obtained:
Show more

25 Read more

Trefftz method for solving two-dimensional temperature field of boiling fluid flowing along the minichannel

Trefftz method for solving two-dimensional temperature field of boiling fluid flowing along the minichannel

After deaeration, there is a laminar flow of FC-72 working fluid in the main loop in the experimental set-up. The liquid, at the temperature below its boiling point, flows laminarly into the minichannel (#1), figure 1. When the desired pressure and flow rate are reached, the gradual increase in the electric power supplied to the heating foil results in an increased heat flux transferred to the liquid in the minichannel. The current supplied via copper elements (#9) to the heating foil (#2) is controlled by an electrical system equipped with an inverter welder (#16). This leads to the incipience and next to the development of nucleate boiling. Then, the current supplied to the foil is reduced gradually. Thanks to the liquid crystal layer located on its surface contacting the glass it is possible to measure the temperature distribution on the heating wall. Flow structure observation is carried out simultaneously at the opposite side of the minichannel.
Show more

7 Read more

Design and CFD Analysis of Air Foil

Design and CFD Analysis of Air Foil

Based on the CFD analysis of the flow over NACA 0012 air foil we can conclude that at the two degree of AOA there is no lift force generated and if we want to increase amount of lift force and value of lift co efficient then we have to increase the value of AOA. By doing

5 Read more

Measurement of antibacterial properties of foil-backed electrospun nanofibers

Measurement of antibacterial properties of foil-backed electrospun nanofibers

Current methodologies for evaluation of antibacterial properties of traditional textiles are not applicable to foil‑backed, poorly‑absorbent electrospun nanofiber materials, since existing test methods require absorbent fabrics. Since electrospun nanofibers are adhered to the foil backing only by electrostatic interactions, methods used to evalu‑ ate antibacterial properties of surfaces cannot be used because these protocols cause the nanofibers to lift from the foil backing. Therefore, a novel method for measurement of the antibacterial properties of electrospun metallic foil‑backed nanofiber materials was developed. This method indicated that acetate‑based nanofibers manufactured to contain 5 to 30 weight percent of cold‑pressed hemp seed oil or full‑spectrum hemp extract inhibited the growth of Staphylococcus aureus in a dose‑dependent man‑ ner, from 85.3% (SEM = 2.2) inhibition to 99.3% (SEM = 0.15) inhibition, respectively. This testing method represents an advanced manufacturing prototype procedure for assessment of antibacterial properties of novel electrospun, metallic foil‑backed nanofiber materials.
Show more

11 Read more

Free surface interaction of a ‘T foil’ hydrofoil

Free surface interaction of a ‘T foil’ hydrofoil

Hydrofoils are used to reduce hull drag by lifting a vessel clear of the sea surface or to a lesser extent by reducing a vessel’s dynamic displacement. Once a vessel has been raised above the sea surface, only the hydrodynamic drag originating from the hydrofoils remains. T-foil hydrofoils, are a type of hydrofoil where a horizontal lifting foil is mounted at the base of a vertical strut beneath a vessel. T-foils permit the lifting foil to remain fully immersed, thus providing a smoother ride than surface piercing dihedral foils due to reduced wave interaction. Lifting foils on hydrofoil borne maritime vessels operate in close proximity to the sea surface - at low immersion - due to the requirement to minimize strut drag through reduction of strut immersion and vessel draft restrictions when in displacement mode. Binns et al. (2008) reported a drag optimisation point based on Froude number of particular note for sailing vessels such as the International Moth Class sailing dinghy and the International America’s Cup Class foiling catamaran yacht.
Show more

222 Read more

Automatic Mechanism for the Feeding of Foil Bags in Box

Automatic Mechanism for the Feeding of Foil Bags in Box

the process of packaging Silver foil bags into the boxes and decrease operating costs, I decided to design a machine that would place the foil bags silver coming out of the x-ray machine into the box. With very few pre-existing designs for automated packaging/loading of these types of bags into the moving boxes without making the conveyor carrying boxes to stop, I essentially had to come up with a design from scratch. To make my machine as simple as possible, I decided to make it primarily conveyor system based. Using both the graphical and analytical methods for conveyor linkage synthesis and with the aid of computer aided design software such as Factory I/O, Solidworks; I was able to determine the details of my system to be designed.
Show more

9 Read more

Determination of oxygen permeability of polyethylene and polypropylene nonwoven fabric foils

Determination of oxygen permeability of polyethylene and polypropylene nonwoven fabric foils

was made in the company Gabriel-Chemie, Lázně Bohdaneč, Czech Republic. Then the polyethyl- ene Polyten®MLB black&white foils were stud- ied, which were made in the company Chemosvit Fólie, a.s., Svit, Slovak Republic. The thickness of the foils was 90 m m. Black polypropylene nonwo- Table 2. Measured quantities of (A) the PE Bralen 2-63 with 9% coloured concentrate Maxithen HP 533041 – violet foil (thickness 50 m m), (B) PE Polyten®MLB black&white foil (thickness 90 m m) and (C) PP polypropylene nonwoven fabric foil (thickness 50 m m) at the air temperature 295 K
Show more

9 Read more

Apology and Medical Mistake: Opportunity or Foil?

Apology and Medical Mistake: Opportunity or Foil?

debriefed the mock jurors, they learned that the failure to disclose the error "exacerbated the belief that the organization should be punished for more than compe[r]

41 Read more

Studies on New Type Current Collectors for Polyaniline Batteries

Studies on New Type Current Collectors for Polyaniline Batteries

Five kinds of possible material as current collectors for PANI batteries were selected. Stainless steel (SS) was offered by Dongguan Mingnuo metal materials co., LTD. Aluminum foil (AF) was supplied by National medicine group chemical reagent co., LTD. Lead foil (LF) came from Qingdao Yongjiasheng industry and trade co., LTD. They were polished with abrasive paper to remove the oxidation layer on the surface before tested. Conductive plastics (CP) came from Shenzhen Xinrida technology co., LTD. Carbon fiber (CF) was supplied by Nantong Senyou carbon fiber co., LTD.
Show more

13 Read more

Progress status in fabrication of HBC stripper foil for 3-GeV RCS at J-PARC in Tokai site

Progress status in fabrication of HBC stripper foil for 3-GeV RCS at J-PARC in Tokai site

Some vapor deposition conditions for new foil fabrication are different from the original conditions because of repair and overhaul of the deposition apparatus. Furthermore, detailed procedure to fabricate the HBC foils prescribed by Sugai is not available. In such an environment, we started an attempt to fabricate the new foil at the Tokai site by recalling how he had fabricated the HBC foils previously. And the vacuum components were treated with extra care to prevent any contamination. For example, the glass plates were washed with an ultrasonic cleaning machine, and the deposited foils both before and after their release from the glass plate were stored in a desiccator. After several trial deposition tests, we successfully fabricated a new HBC foil at the JAEA Tokai site. (As mentioned before, we call the new foils J-HBC foil.) Subsequently, the performance of the J-HBC foil was evaluated before installation in the RCS and to use for the user operation.
Show more

7 Read more

The solution of the two-dimensional inverse heat transfer problem with the use of the FEM in combination with Trefftz functions

The solution of the two-dimensional inverse heat transfer problem with the use of the FEM in combination with Trefftz functions

Boiling incipience is recognised as a sudden drop in the heating surface temperature that follows its systematic increase, at constant capacity of the internal heat source. It is called “boiling front” and it shifts in the direction opposite to the liquid flow in the minichannel with the increase in the heat flux supplied to the heating surface [5,9-13]. Figure 6 shows hue distribution on the foil surface during increasing heat flux, obtained with liquid crystal thermography, with a visible “boiling front” (BI). The “boiling front” occurrence for the investigated enhanced heating foil was analysed in [9] of this collection of conference papers.
Show more

11 Read more

Co design/simulation of flip chip assembly for high voltage IGBT packages

Co design/simulation of flip chip assembly for high voltage IGBT packages

The layout of the fabricated LIGBT developed in 0.6μm/5V bulk silicon technology is shown in Fig. 4(a), and 3 dimensional schematic of the LIGBT device structure presented in Fig. 4(b). The PCB package design for an effective cooling of the LIGBT is presented in Fig.3 (a). The package is designed for optimal thermal performance using vias linking the device solder balls and top PCB copper layer to the base which can be used for cooling. An additional copper foil is used as a heatsink to extract heat from the backside of the device and the PCB copper layer. Solder is used to attach the copper foil to the device backside to improve thermal performance.
Show more

5 Read more

Show all 10000 documents...