Abstract: An ion implantation system, ion source, and method are provided having a gaseous aluminum-based ion source material. The gaseous aluminum-based ion source material can be, or include, dimethylaluminum chloride (DMAC), where the DMAC is a liquid that transitions into vapor phase at room temperature. An ion source receives and ionizes the gaseous aluminum-based ion source material to form an ion beam. A low-pressure gas bottle supplies the DMAC as a gas to an arc chamber of the ion source by a primary gas line. A separate, secondary gas line supplies a co-gas, such as a fluorine-containing molecule, to the ion source, where the co-gas and DMAC reduce an energetic carbon cross-contamination and/or increase doubly charged aluminum.

Abstract: An example system includes a particle accelerator to produce a particle beam to treat a patient and a carrier having openings including a first opening and a second opening. The carrier is made of a material that inhibits transmission of the particle beam and the carrier is located between the particle accelerator and the patient. A control system is configured to control movement of the particle beam to the first opening to enable at least part of the particle beam to reach the patient, to change an energy of the particle beam while the particle beam remains stationary at the first opening, and to control movement of the particle beam from the first opening to the second opening. The example system also includes an energy degrader that includes at least some boron carbide.

Abstract: The invention relates to a method for the spectrometry, in particular mass spectrometry, ion-mobility spectrometry, or optical emission spectroscopy, of a sample, comprising the following steps: providing a solid-state generator for generating a high-frequency signal, having a control element for varying the power and/or frequency of the signal, providing a plasma ignition head fed by the signal for generating a plasma jet, applying the plasma jet to a sample, performing a first measuring operation, wherein the plasma jet is generated with a first power of the solid-state generator and a spectrum emitted by the sample, preferably charged ions and/or optical spectrum, is recorded by means of a spectrometer, wherein the first power leads to a soft ionization of the sample, and performing a second measuring operation on the same sample, wherein the plasma jet is generated with a second power of the solid-state generator and a spectrum emitted by the sample, preferably charged atoms and/or optical spectrum, is re

Abstract: A system and method for varying the temperature of a faceplate for an ion source is disclosed. The faceplate is held against the chamber walls of the ion source by a plurality of fasteners. These fasteners may include tension springs or compression springs. By changing the length of the tension spring or compression spring when under load, the spring force of the spring can be increased. This increased spring force increases the compressive force between the faceplate and the chamber walls, creating improved thermal conductivity. In certain embodiments, the length of the spring is regulated by an electronic length adjuster. This electronic length adjuster is in communication with a controller that outputs an electrical signal indicative of the desired length of the spring. Various mechanisms for adjusting the length of the spring are disclosed.

Abstract: Apparatus and methods are described for use with a vaporizer that vaporizes at least one active ingredient of a plant material. In response to receiving a first input to the vaporizer, the plant material is heated, in a first heating step. An indication of the temperature of the plant material is detected, and, in response to detecting an indication that the temperature of the plant material is at a first temperature, the first heating step is terminated, by withholding causing further temperature increase of the plant material. The first temperature is less than 95 percent of the vaporization temperature of the active ingredient. Subsequently, a second input is received at the vaporizer. In response thereto, the plant material is heated to the vaporization temperature, in a second heating step. Other applications are also described.

Abstract: The invention generally relates to systems and methods for sample analysis. In certain embodiments, the invention provides a system for analyzing a sample that includes a probe including a material connected to a high voltage source, a device for generating a heated gas, and a mass analyzer.

Abstract: Femtoliter to milliliter volumes of one or a plurality of different liquids are accurately transported, dispensed and/or treated where the fluids are energized purely electrokinetically or in a hybrid mode where auxiliary coordinated energy sources including but not limited to pneumatic, piezoelectric; peristaltic; ultrasonic; thermal; gravitational, acoustic are employed concurrently or sequentially to transport liquids for various purposes from diverse devices to targets of all types being made of a conductive, non-conductive or semiconductive materials. Liquids in nested Gaussian surfaces or common liquid handling devices (e.g.

Abstract: An apparatus that generates molecular ions and methods to generate molecular ions are disclosed. At least a first species is ionized in an ion source. The first species ions and/or first species combine to form molecular ions. These molecular ions may be transported to a second chamber, which may be an arc chamber or diffusion chamber, and are extracted. The molecular ions may have a larger atomic mass than the first species or first species ions. A second species also may be ionized with the first species to form molecular ions. In one instance, the first and second species are both molecules.

Abstract: A system and method comprising an ion production chamber having a plasma source disposed in said chamber, a harvest gas disposed to flow through the chamber from an inlet to an outlet, and a jet, said jet operable to introduce a sample into the harvest gas flow. In some embodiments the system includes using helium as the harvest gas. Certain embodiments include introducing a sample perpendicular to the harvest gas flow and using multiple sample introduction jets to increase mixing efficiency. The charge sample may be coupled to a MEMS-based electrometer.

Abstract: Provided is a mass spectrometer capable of easy exchange of a measurement sample and suppressing a carryover. The mass spectrometer includes a mass spectrometry section, an ion source the internal pressure of which is reduced by a differential pumping from the mass spectrometry section and the ion source ionizes the sample gas, a sample container in which the sample gas is generated by vaporizing the measurement sample, a thin pipe that introduces the sample gas generated in the sample container into the ion source, an elastic tube of openable and closable that connects the sample container and the thin pipe, a pair of weirs that closes or opens the elastic tube so as to sandwich the elastic tube, and a cartridge that integrates the sample container, the thin pipe, and the elastic tube, and is detachable in a lump from a main body of the mass spectrometer.

Abstract: The present invention is directed to a method and device to desorb an analyte using heat to allow desorption of the analyte molecules, where the desorbed analyte molecules are ionized with ambient temperature ionizing species. In various embodiments of the invention a current is passed through a mesh upon which the analyte molecules are present. The current heats the mesh and results in desorption of the analyte molecules which then interact with gas phase metastable neutral molecules or atoms to form analyte ions characteristic of the analyte molecules.

Abstract: The invention generally relates to systems and methods for mass spectrometry analysis of microorganisms in samples.

Abstract: The invention generally relates to systems and methods for sample analysis. In certain embodiments, the invention provides a system for analyzing a sample that includes a probe including a material connected to a high voltage source, a device for generating a heated gas, and a mass analyzer.

Abstract: A ion source comprises: a chamber, an injection to inject matter into the chamber, wherein said matter comprises at least a first species, a tip with an apex located in the chamber, wherein the apex has a surface made of a metallic second species, a generator to generate ions of said species, and a regulation system adapted to set operative conditions of the chamber to alternatively generate ions from the gaseous first species, and ions from the non-gaseous metallic second species.

Abstract: Methods and apparatus for desolvating flowing liquid streams while retaining temporal resolution of dissolved substrates are disclosed. A novel small-scale self-regulating spray dryer preserves temporal resolution while desolvating a liquid chromatography eluent stream and depositing the solute onto an optical surface for infrared spectrographic analysis. The liquid eluent is pumped through a heated nebulizer to create a high-speed jet of solute containing liquid and solvent vapor. This jet is directed circumferentially inside a hot cylindrical cavity. Centrifugal force causes the larger liquid droplets to travel along the outer diameter of the cavity. The cavity surface is heated to cause the droplets to film boil. Film boiling reduces droplet contact with the cavity surface thereby retaining the solute in the droplets. The solute temperature is limited by controlling the pressure into which the solvent evaporates from the droplets.

Abstract: An extreme ultraviolet light source apparatus generating an extreme ultraviolet light from plasma generated by irradiating a target material with a laser light within a chamber, and controlling a flow of ions generated together with the extreme ultraviolet light using a magnetic field or an electric field, the extreme ultraviolet light source apparatus comprises an ion collector device collecting the ion via an aperture arranged at a side of the chamber, and an interrupting mechanism interrupting movement of a sputtered particle in a direction toward the aperture, the sputtered particle generated at an ion collision surface collided with the ion in the ion collector device.

Abstract: The present invention relates to the design and use of an ion source with a rapid beam current controller for experimental and medicinal purposes. More particularly, the present invention relates to the design and use of a laser ion source with a magnetic field applied to confine a plasma flux caused by laser ablation.

Abstract: The invention generally relates to systems and methods for mass spectrometry analysis of microorganisms in samples.

Abstract: The present invention is directed to a method and device to desorb an analyte using heat to allow desorption of the analyte molecules, where the desorbed analyte molecules are ionized with ambient temperature ionizing species. In various embodiments of the invention a current is passed through a mesh upon which the analyte molecules are present. The current heats the mesh and results in desorption of the analyte molecules which then interact with gas phase metastable neutral molecules or atoms to form analyte ions characteristic of the analyte molecules.

Abstract: PVD and HPHT methods and apparatus for producing materials, for example nitrides, are disclosed.

Abstract: The invention relates generally to sample ionization, and provides ionization probe assemblies, systems, computer program products, and methods useful for this purpose.

Abstract: An ionic liquid ion source can include a microfabricated body including a base and a tip. The body can be formed of a porous material compatible with at least one of an ionic liquid or room-temperature molten salt. The body can have a pore size gradient that decreases from the base of the body to the tip of the body, such that the at least one of an ionic liquid or room-temperature molten salt is capable of being transported through capillarity from the base to the tip.

Abstract: An apparatus for chemical separations includes a microfluidic substrate having an outlet aperture for outputting an eluent of a sample, a spray unit having an inlet to receive the eluent and an outlet to emit a spray of the eluent, and a force-applying unit. The spray unit has a deformable portion defining the inlet and having an elastic modulus that is lower than an elastic modulus of the microfluidic substrate. The force-applying unit, such as a spring, is disposed to urge the deformable portion in contact with the substrate to form a substantially fluid-tight seal.

Abstract: A spinning cell device is described for fast and convenient standardization and analysis of constituents and isotopes in solid samples by laser ablation inductively coupled plasma (LA-ICP) spectrometry. The method and apparatus for performing the method require the sample under test and a standard to be spun during ablation allowing the quasi-simultaneous ablation of both materials. The aerosols resulting from the ablation of sample and standard are mixed in the ablation cell allowing quantification of the ablated metals by the method of standard addition or isotope dilution. The relative proportion of standard verses sample ablated can be changed by altering the trajectory of the laser beam. The ablated aerosol is swept into an inductively coupled plasma by a carrier gas and analyzed by mass spectrometry.

Abstract: An apparatus for generating ions includes an Electrospray ionization source configured to provide a spray of charged droplets from a sample solution during operation of the apparatus; an atmospheric pressure chemical ionization (APCI) source including a corona discharge needle configured to produce a corona discharge that further ionizes the spray during operation of the apparatus; and a gas delivery system configured to deliver a gas flow to the corona discharge needle during operation of the apparatus, wherein the gas flow comprises a reagent ion gas which facilitates ionization of the spray by the corona discharge.

Abstract: A droplet generation and detection device may include: a droplet generation unit for outputting a charged droplet; at least one droplet sensor including a magnetic circuit including a coil configured of an electrically conductive material, the magnetic circuit being disposed such that the charged droplet passes around the magnetic circuit, and a current detection unit for detecting current flowing in the coil and outputting a detection signal; and a signal processing circuit for detecting the charged droplet based on the detection signal.

Abstract: A UV liquid treatment system comprises least one UV treatment unit including a unit container having a container interior; a liquid distribution head carried by the unit container; at least one liquid inlet passage in the liquid distribution head and disposed in fluid communication with the unit container interior of the unit container; at least one liquid outlet passage in the liquid distribution head and disposed in fluid communication with the unit container interior of the unit container; a transparent light bulb shield carried by the liquid distribution head and having a shield interior; an assembly cavity in the liquid distribution head and communicating with the shield interior of the light bulb shield; a UV light assembly having a UV light bulb removably seated in the assembly cavity, the UV light bulb disposed in the shield interior of the light bulb shield; and a power source electrically connected to the UV light bulb of the UV light assembly.

Abstract: Target molecules in a sample can be detected at an improved sensitivity by means of a mass spectrometer. A sample with or without a matrix is placed on a substrate and irradiated with a converged and pulsed primary beam selected from an ion beam, a neutral particle beam or a laser beam. Secondary ions and neutral molecules are emitted along with protons from the irradiated point of the sample as an electric field is applied between the substrate and an extraction electrode disposed above the substrate. A proton-control electrode is arranged in axial symmetry with the trajectory of the primary beam. A voltage is applied thereto so that the generated electric field decelerates the flying protons to raise their adhering efficiency to the flying neutral molecules.

Abstract: Methods and apparatus for desolvating flowing liquid streams while retaining temporal resolution of dissolved substrates are disclosed. A novel small-scale self-regulating spray dryer preserves temporal resolution while desolvating a liquid chromatography eluent stream and depositing the solute onto an optical surface for infrared spectrographic analysis. The liquid eluent is pumped through a heated nebulizer to create a high-speed jet of solute containing liquid and solvent vapor. This jet is directed circumferentially inside a hot cylindrical cavity. Centrifugal force causes the larger liquid droplets to travel along the outer diameter of the cavity. The cavity surface is heated to cause the droplets to film boil. Film boiling reduces droplet contact with the cavity surface thereby retaining the solute in the droplets. The solute temperature is limited by controlling the pressure into which the solvent evaporates from the droplets.

Abstract: An EUV light source device properly compensates the wave front of laser beam which is changed by heat. A wave front compensator and a sensor are provided in an amplification system which amplifies laser beam. The sensor detects and outputs changes in the angle (direction) of laser beam and the curvature of the wave front thereof. A wave front compensation controller outputs a signal to the wave front compensator based on the measurement results from the sensor. The wave front compensator corrects the wave front of the laser beam to a predetermined wave front according to an instruction from the wave front compensation controller.

Abstract: A device and associated methods of operations are disclosed for interfacing on ion trap to a mass analyzer, such as a TOF mass analyzer. The device includes a plurality of sequentially arranged confinement cells having fixed locations. A group of ions, e.g., ions within a relatively narrow window of mass-to-charge ratio, is received by the device from the ion trap, undergoes fragmentation, and is transported through the device from a first to final confinement cell by a series of transfers between adjacent cells. The ion group is confined in each cell for a prescribed cooling period. By providing a suitable aggregate ion confinement time and by enabling concurrent transport and cooling of successively ejected ion groups, the ions are cooled sufficiently to enable the acquisition of mass spectra at high resolution, without having to substantially delay the ejection of a subsequent group of ions from the ion trap until cooling of the previous group is completed.

Abstract: An Atmospheric Pressure Chemical Ionization (APCI) source interfaced to a mass spectrometer is configured with a corona discharge needle positioned inside an APCI inlet probe assembly. Liquid sample flowing into the APCI inlet probe is nebulized and vaporized prior to passing through the corona discharge region all contained in the APCI inlet probe assembly. The APCI probe is configured to shield the electric field from the corona discharge region while allowing penetration of an external electric field to focus APCI generated ions into an orifice into vacuum for mass to charge analysis. Ions that exit the APCI probe are directed only by external electric fields and gas flow maximizing ion transmission into a mass to charge analyzer. Sample ions and gas phase reagent ions are generated in the APCI probe from liquid or gas inlet species or mixtures of both.

Abstract: An extreme ultraviolet light source apparatus generating an extreme ultraviolet light from plasma generated by irradiating a target material with a laser light within a chamber, and controlling a flow of ions generated together with the extreme ultraviolet light using a magnetic field or an electric field, the extreme ultraviolet light source apparatus comprises an ion collector device collecting the ion via an aperture arranged at a side of the chamber, and an interrupting mechanism interrupting movement of a sputtered particle in a direction toward the aperture, the sputtered particle generated at an ion collision surface collided with the ion in the ion collector device.

Abstract: An extreme ultraviolet light source apparatus has a magnetic field generator which generates a magnetic field region around a direction of the magnetic field passing through a plasma region in which a plasma is to be generated and converges charged particles including ion emitted from the plasma region toward the direction of the magnetic field, a first charged particle collector (receiver) mounted at both sides of an axis of the magnetic field in the magnetic field region in order to collect (receive) the charged particles converged by the magnetic field, a target supply unit supplying a target from a nozzle located outside a converging region in which the charged particles are to be converged inside the magnetic field region in an extreme ultraviolet light generating chamber, and a target collector located at a position opposite to the nozzle, the target retrieval portion retrieving a residual target which does not contribute to generation of the plasma.

Abstract: An electrospray ion source apparatus comprises: a plurality of emitter capillaries, each comprising an internal bore for transporting a portion of a liquid sample from a source, an electrode portion for providing a first applied electric potential and an emitter tip for emitting a cloud of charged particles generated from the liquid sample portion; a counter electrode for providing a second applied electric potential different from the first applied electric potential; and at least one shield electrode disposed at least partially between the counter electrode and the emitter tip of at least one of the emitter capillaries for providing a third applied electric potential intermediate to the first and second applied electric potentials, wherein the at least one shield electrode is configured such that provision of the third applied electric potential to the at least one shield electrode minimizes electric field interference effects between the plurality of emitter capillaries.

Abstract: An assembly includes a cold ion source and a chip. The cold ion source is fixed to the chip so that ions from the ion source can enter an acceleration channel in the chip. In one specific example, the ion source includes an ion exchange membrane that produces cold ions in that the ions as produced have an energy of less than 30 eV. The chip includes a substrate (such as a semiconductor substrate or a glass substrate) and a dielectric layer disposed on substrate, where the acceleration channel is a channel formed into the dielectric layer. In one specific example, the assembly is part of a Direct Write On Wafer (DWOW) printing system. The DWOW printing system is useful in semiconductor processing in that it can direct write an image onto a 300 mm diameter wafer in one minute.

Abstract: A laser-ablation plasma generator generates laser-ablation plasma from a target in a vacuum vessel. An ion beam extractor generates an ion beam by extracting ions included in the laser-ablation plasma from the vacuum vessel. An ion detector detects unintended ions other than intended ions, which are obtained by ionizing the elements in the target, out of ions in the vacuum vessel and outputs a detection signal representing a value which is a number of the unintended ions or a mixing ratio of the unintended ions to the intended ions as a detection result. The ion source using the laser beam makes it possible to normally monitor unintended ions other than intended ions out of ions in the vacuum vessel.

Abstract: A method of enhanced speciation of both positive and negatives species in an analyte is disclosed. The method can include producing a first analyte solution comprising an analyte composition and an effective amount of silver triflate, and analyzing the first analyte solution with an electrospray ionization mass spectrometer. The method can also include producing a second analyte solution comprising a portion of the analyte composition and an effective amount of a compound of formula I, and analyzing the second analyte solution with an electrospray ionization mass spectrometer. The compound of formula I is [NX+][OH?], where X is a linear, branched, or cyclic C1-C10 alkane; an aryl; a heterocyclic aromatic; or a heterocyclic moiety.

Abstract: An apparatus for electrospray ionization may include: a platform including an inlet port, a first channel connected to the inlet port, a second channel connected to the first channel, and an outlet port connected to the second channel; a nebulizer provided in the first channel and configured to spray inert gas to a sample sprayed into the first channel through the inlet port; and a focusing lens provided in the second channel and configured to focus ions produced from the sprayed sample toward the outlet port.

Abstract: An extreme ultraviolet light source apparatus provided with a magnetic field forming unit having sufficient capability of protection against ions radiated from plasma while using a relatively small magnetic source. The apparatus includes: a target nozzle for injecting a target material; a driver laser for applying a laser beam to the target material to generate plasma; a collector mirror for collecting extreme ultraviolet light radiated from the plasma; and a magnetic field forming unit including at least one magnetic source and at least one magnetic material having two leading end parts projecting from the at least one magnetic source to face each other with a plasma emission point in between, and forming a magnetic field between a trajectory of the target material and the collector mirror.

Abstract: An electrostatic atomizing device comprises an electrostatic atomizing part (2) applying high-voltage to water supplied to an atomization electrode (1), thereby generating negatively-charged minute water particles, a positive ion generator (3) being configured to generate positive ions, and a controller (16) being configured to control operation of said electrostatic atomizing part (2) and said positive ion generator (3). Said controller (16) controls so as to cause said electrostatic atomizing part (2) to generate the negatively-charged minute water particles, after the positive ions are generated by said positive ion generator (3).

Abstract: An electrospray ion source for a mass spectrometer for generating ions of an analyte from a sample comprising the analyte dissolved in a liquid solvent comprises: an electrode receiving the sample and comprising at least a first plurality of protrusions protruding from a base, each protrusion of the at least a first plurality of protrusions having a respective tip; and a voltage source, wherein, in operation of the electrospray ion source, the sample is caused to move, in the presence of a gas or air, from the base to each protrusion tip along a respective protrusion exterior so as to form a respective stream of charged particles emitted towards an ion inlet aperture of the mass spectrometer under application of voltage applied to the electrode from the voltage source.

Abstract: A nozzle protection device capable of protecting a target nozzle from heat of plasma without disturbing formation of a stable flow of a target material in an LPP type EUV light source apparatus. This nozzle protection device includes a cooling unit which is formed with an opening for passing the target material therethrough, and which is formed with a flow path for circulating a cooling medium inside, and an actuator which changes a position or a shape of the cooling unit between a first state of evacuating the cooling unit from a trajectory of the target material and a second state of blocking heat radiation from the plasma to the nozzle by the cooling unit while securing a path of the target material in the cooling unit.

Abstract: An EUV light source device properly compensates the wave front of laser beam which is changed by heat. A wave front compensator and a sensor are provided in an amplification system which amplifies laser beam. The sensor detects and outputs changes in the angle (direction) of laser beam and the curvature of the wave front thereof. A wave front compensation controller outputs a signal to the wave front compensator based on the measurement results from the sensor. The wave front compensator corrects the wave front of the laser beam to a predetermined wave front according to an instruction from the wave front compensation controller.

Abstract: An aerosol particle analyzer includes a laser ablation chamber, a gas-filled conduit, and a mass spectrometer. The laser ablation chamber can be operated at a low pressure, which can be from 0.1 mTorr to 30 mTorr. The ablated ions are transferred into a gas-filled conduit. The gas-filled conduit reduces the electrical charge and the speed of ablated ions as they collide and mix with buffer gases in the gas-filled conduit. Preferably, the gas filled-conduit includes an electromagnetic multipole structure that collimates the nascent ions into a beam, which is guided into the mass spectrometer. Because the gas-filled conduit allows storage of vast quantities of the ions from the ablated particles, the ions from a single ablated particle can be analyzed multiple times and by a variety of techniques to supply statistically meaningful analysis of composition and isotope ratios.

Abstract: The present invention relates to a debris mitigation device for use with a radiation source (2) generating optical radiation, in particular extreme ultraviolet radiation (EUV) or soft x-rays, and emitting undesired substances and/or particles which can deposit on optical surfaces in a radiation path of said radiation source (2), and to a corresponding drive assembly. The debris mitigation device comprises at least one rotating foil trap (5) and the drive assembly. The drive assembly comprises a driving motor (14) and a driving axis (10), to which the rotating foil trap (5) is fixed. The driving motor (14) and bearings (13) supporting the driving axis (10) are enclosed in a casing (20) having an aperture for the driving axis (10) and at least one outlet opening (21) for a sealing gas. The outlet opening (21) is connectable to a pump for pumping out the sealing gas.

Abstract: An apparatus for direct analysis of the redox products, or intermediates, of an electrochemical reaction by coupling an electrochemical cell to desorption electrospray ionization mass spectrometry.

Abstract: An ionic liquid ion source can include a microfabricated body including a base and a tip. The microfabricated body can be formed of a porous metal compatible (e.g., does not react or result in electrochemical decaying or corrosion) with an ionic liquid or a room-temperature molten salt. The microfabricated body can have a pore size gradient that decreases from the base of the body to the tip of the body, so that the ionic liquid can be transported through capillarity from the base to the tip.

Abstract: The mass spectrometer includes an ion source; a mass spectrometry part; a sample container; a heater for the sample container; a first gas tube connected to the sample container to introduce a gas into the sample container; and a second gas tube connected to the sample container to transfer a headspace gas of the sample container to the ion source, in which the ion source generates ions of the headspace gas and the mass spectrometry part performs mass spectrometry of the ions. Thereby, the mass spectrometer as a drug detection equipment can analyze various drugs in urine rapidly and with high sensitivity.

Abstract: An electrically conductive heat-blocking plate 11 with an opening 12 for allowing thermions to pass through is provided between a filament 3, whose temperature can be as high as 2000° to 3000° C., and an ionization chamber 2. The heat-blocking plate 11 is thermally connected via an aluminum block 10 to a heater for maintaining the ionization chamber 2 within a range temperature from 200° to 300° C., and also electrically set at a ground potential, which is approximately equal to the potential of the ionization chamber 2. The heat-blocking plate 11 blocks the radiation heat that the filament 3 emits when energized. Thus, the wall of the ionization chamber 2 is prevented from being locally heated to an abnormally high temperature. As a result, the inner space of the ionization chamber 2 is maintained at an approximately uniform temperature, and the noise due to the decomposition of a metallic material by abnormal heating is prevented.