摘要:

ACU undergraduates have played significant roles in the experimental program in baryon spectroscopy at the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). The most recent data consist primarily of cross sections for&pgr;−p→Neutralsat 130–750 MeV/c obtained with the Crystal Ball detector. An overview of the undergraduate involvement will be presented, culminating with the analysis of the data to obtain differential cross sections for&pgr;−p→&pgr;0n.©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1395505

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

As a neutron tube manufacturer, SODERN is now in charge of manufacturing tritium targets for accelerators, in cooperation with CEA/DAM/DTMN in Valduc. Specific deuterium and tritium targets are manufactured on request, according to the requirements of the users, starting from titanium target on copper substrate, and going to more sophisticated devices. A wide range of possible uses is covered, including thin targets for neutron calibration, thick targets with controlled loading of deuterium and tritium, rotating targets for higher lifetimes, or large size rotating targets for accelerators used in boron neutron therapy. Activity of targets lies in the 1 to 1000 Curie, diameter of targets being up to 30 cm. Special targets are also considered, including surface layer targets for lowering tritium desorption under irradiation, or those made from different kinds of occluders such as titanium, zirconium, erbium, scandium, with different substrates. It is then possible to optimize either neutron output, or lifetime and stability, or thermal behavior. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1395506

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

For the preparation of actinide targets electrochemical methods have been used. Electrolytic deposition in form of the actinide hydroxide on a Ta- or Ti-backing is performed from an aqueous solution, applying current densities up to several A/cm2. In the case of Be or Al as backing material, molecular plating was applied. Here, the deposition from an organic solution (usually isopropanol) with current densities of only a few mA/cm2and voltages up to 1000 V occurs. With these techniques target densities up to 1 mg/cm2are possible. In most cases, prior to deposition, chemical separation procedures are required to ensure high purity of the target material. Targets with thicknesses ranging from fg/cm2up to mg/cm2for the actinides Ac to Es have been produced. A brief survey for the applications of actinide targets in chemical and physical studies is given. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1395507

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

We report on the status of target development for the heavy-element program at GSI, namely for the SHIP experiment. We present some recent results in enhancing the durability of the targets irradiated with the more and more intense heavy-ion beams. The enhancement of the beam intensity is necessary in order to keep beam times at reasonable length despite cross sections in the picobam region. We synthesised new compound targets on208Pb-basis with significantly higher melting temperatures and built up a target monitoring system. To investigate the high-current targets and develop an active cooling system we built up a test bench for offline experiments. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1395508

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The creation of a specific heavy ion residue via heavy ion fusion can usually be achieved through a number of beam and target combinations. Sometimes it is necessary to choose combinations with rare beams and/or difficult targets in order to achieve the physics goals of an experiment. A case in point was a recent experiment to produce152Dyat very high spins and low excitation energy with detection of the residue in a recoil mass analyzer. Both to create the nucleus cold and with a small recoil-cone so that the efficiency of the mass analyzer would be high, it was necessary to use the80Seon76Gereaction rather than the standard48Caon108Pdreaction. Because the recoil velocity of the152Dyresidues was very high using this symmetric reaction (5&percent; v/c), it was furthermore necessary to use a stack of two thin targets to reduce the Doppler broadening. Germanium targets are fragile and do not withstand high beam currents, therefore the76Getarget stacks were mounted on a rotating target wheel. A description of the76Getarget stack preparation will be presented and the target performance described. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1395509

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

In heavy-ion physics, high beam currents can eventually melt or destroy the target. Tightly focused beams on stationary targets of modest melting point will exhibit short lifetimes. Defocused or “wobbled” beams are employed to enhance target survival. Rotating targets using large diameter wheels can help overcome target melting and allow for higher beam currents to be used in experiments. The purpose of the calculations in this work is to try and predict the safe maximum beam currents which produce heat loads below the melting point of the target material. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1395510

出版商:AIP    

年代:1901

数据来源: AIP