Pumped helium system for cooling positron and electron traps to 1.2K

Wrubel, Jonathan; Gabrielse, Gerald; Kolthammer, W. Steven; Larochelle, P.; McConnell, Robert; Richerme, Philip; Grzonka, D.; Oelert, W.; Sefzick, T.; Zieliński, Marcin; Borbely, Joseph Steven; George, M. C.; Hessels, E. A.; Storry, C. H.; Weel, M.; Müllers, A.; Walz, J.; Speck, A.

doi:10.1016/j.nima.2011.01.030

Cited by 7 publications

(10 citation statements)

References 23 publications

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“…To increase the likelihood that cold " H would be produced, we cooled the electrodes of the traps containing " p and e þ to 1.2 K [12], demonstrated that e þ or e À stored within these thermalized at 20 K [13], and prepared up to…”

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confidence: 99%

Trapped Antihydrogen in Its Ground State

2012

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Antihydrogen atoms (H¯) are confined in an Ioffe trap for 15-1000 s-long enough to ensure that they reach their ground state. Though reproducibility challenges remain in making large numbers of cold antiprotons (p¯) and positrons (e(+)) interact, 5±1 simultaneously confined ground-state atoms are produced and observed on average, substantially more than previously reported. Increases in the number of simultaneously trapped H¯ are critical if laser cooling of trapped H¯ is to be demonstrated and spectroscopic studies at interesting levels of precision are to be carried out.

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confidence: 99%

Trapped Antihydrogen in Its Ground State

2012

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“…The general design principles of the capillary system are based on DeLong et al [8], wherein they describe a two stage 4 He cryogenic system for a dilution refrigerator. Similar designs are described in various publications [16,17,18,19].…”

Section: No Mechanical Valves or Other Moving Partsmentioning

confidence: 86%

“…Figure 17 shows the temperature spectral density as measured by MT and SFT thermometers (Silicon Diode DT-470) as well as a Cernox thermometer mounted on the edge of the X2 focal plane. 17 The data, derived from a five hour period during which all telescopes were operational, provide an upper limit for focal plane temperature fluctuations.…”

Section: In-flight Thermal Behaviormentioning

confidence: 99%

The thermal design, characterization, and performance of the S pider long-duration balloon cryostat

Gudmundsson

Amiri

Benton³

et al. 2015

Cryogenics

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We describe the Spider flight cryostat, which is designed to cool six millimeter-wavelength telescopes during an Antarctic long-duration balloon flight. The cryostat, one of the largest to have flown on a stratospheric payload, uses liquid 4 He to deliver cooling power to stages at 4.2 and 1.6 K. Stainless steel capillaries facilitate a high flow impedance connection between the main liquid helium tank and a smaller superfluid tank, allowing the latter to operate at 1.6 K as long as there is liquid in the 4.2 K main tank. Each telescope houses a closed cycle 3 He adsorption refrigerator that further cools the focal planes down to 300 mK. Liquid helium vapor from the main tank is routed through heat exchangers that cool radiation shields, providing negative thermal feedback. The system performed successfully during a 17 day flight in the 2014-2015 Antarctic summer. The cryostat had a total hold time of 16.8 days, with 15.9 days occurring during flight.

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“…There are distinct advantages of orienting the cryogenic Penning trap vertically. A vertical orientation simplifies the cryogenic system design required to maintain a temperature of 4.2 K for the SC solenoid and a temperature of 1.2 K for the Penning trap electrodes [9]. Long thermally insulating supports suspend the Penning trap electrode stack from only a few points at the top of the trap, whereas a far larger number of shorter supports would be required along the length of the cryogenic Penning trap if it were oriented in the horizontal direction, resulting in much poorer thermal isolation.…”

Section: The Atrap Apparatusmentioning

confidence: 99%

“…Stacking of p from subsequent cycles of the AD traps a greater number (up to 10 7 ) of p [8]. A pumped helium system allows for p within a 1.2 K Penning trap [9]. Antiproton plasmas have been further cooled by evaporative cooling [10] or, more recently, by adiabatic cooling [7].…”

Section: Introductionmentioning

confidence: 99%

Efficient transfer of positrons from a buffer-gas-cooled accumulator into an orthogonally oriented superconducting solenoid for antihydrogen studies

et al. 2012

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Positrons accumulated in a room-temperature buffer-gas-cooled positron accumulator are efficiently transferred into a superconducting solenoid which houses the ATRAP cryogenic Penning trap used in antihydrogen research. The positrons are guided along a 9 m long magnetic guide that connects the central field lines of the 0.15 T field in the positron accumulator to the central magnetic field lines of the superconducting solenoid. Seventy independently controllable electromagnets are required to overcome the fringing field of the large-bore superconducting solenoid. The guide includes both a 15• upward bend and a 105• downward bend to account for the orthogonal orientation of the positron accumulator with respect to the cryogenic Penning trap. Low-energy positrons ejected from the accumulator follow the magnetic field lines within the guide and are transferred into the superconducting solenoid with nearly 2 100% efficiency. A 7 m long 5 cm diameter stainless-steel tube and a 20 mm long, 1.5 mm diameter cryogenic pumping restriction ensure that the 10 −2 mbar pressure in the accumulator is isolated well from the extreme vacuum required in the Penning trap to allow for long antimatter storage times. Contents

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Pumped helium system for cooling positron and electron traps to 1.2K

Cited by 7 publications

References 23 publications

Trapped Antihydrogen in Its Ground State

Trapped Antihydrogen in Its Ground State

The thermal design, characterization, and performance of the S pider long-duration balloon cryostat

Efficient transfer of positrons from a buffer-gas-cooled accumulator into an orthogonally oriented superconducting solenoid for antihydrogen studies

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