Target-and recoil chamber

Figure 6.1 Schematic representation of a target-and-recoil chamber arrangement with He-aerosol jet. Reproduced with permission from Trautmann (1995). 1995 R. Oldenbourg Verlag.

Target and recoil chamber are placed in a pile and irradiated with... 

The catcher foil can take the form of a jet of rapidly moving gas, a helium jet. The atoms produced in a nuclear reaction recoil out of a thin target and are stopped in — 1 atm of helium gas in the target chamber. The gas contains an aerosol, typically... 

A schematic plan view of the new on-line separator located on beam line C is given in figure 2. The beam from the accelerator enters the He-jet recoil chamber through a thin Ni window (2mg/cm2), bombards the target and is then stopped in a beam-stopper composed mainly of iron, lead and polystyrene in order to prevent from both neutron and y background. 

A promising development in this direction is the DRIFT detector Snowden-Ifft, Martoff Burwell (2000). This detector consists of a negative ion time projection chamber, the gas in the chamber serving both as WIMP target and as ionization medium for observing the nuclear recoil tracks. The direction of... 

A uranium film (0.5 mg/cm2) deposited on a Ft disc (diameter 1.6 cm) Is used. The Kr activity recoiled from the target Is collected In the recoil chamber and transferred Into an evacuated cell. The Hb daughter Is then collected on a negatively charged strip of Al. 

Figure Bl.24.1. Schematic diagram of the target chamber and detectors used in ion beam analysis. The backscattering detector is mounted close to the incident beam and the forward scattering detector is mounted so that, when the target is tilted, hydrogen recoils can be detected at angles of about 30° from the beam direction. The x-ray detector faces the sample and receives x-rays emitted from the sample.

Feasibility studies have shown that a He-jet activity transport line, with a target chamber placed in the LAMPF main beam line, will provide access to short-lived isotopes of a number of elements that cannot be extracted efficiently for study at any other type of on-line facility. The He-jet technique requires targets thin enough to allow a large fraction of the reaction products to recoil out of the target foils hence, a very intense incident beam current, such as that uniquely available at LAMPF, is needed to produce yields of individual radioisotopes sufficient for detailed nuclear studies. We present the results of feasibility experiments on He-jet transport efficiency and timing. We also present estimates on availability of nuclei far from stability from both fission and spallation processes. Areas of interest for study of nuclear properties far from stability will be outlined. 

There are good prospects for using some simpler dedicated modifications or varieties of the above separators to help future studies of TAE chemistry. Such equipment will mainly serve to separate the recoils from the projectiles to avoid the technical and principal problems due to the heat and ionization produced in the target chamber by the heavy ion beam. A broader spectrum of recoil energies is allowed and so also thicker targets. An ultimately efficient separation from the... 

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