Exotic Beam Summer School 2017: July 23-29, 2017

List of hands-on activities:

1. Precision mass measurements using the Canadian Penning Trap (CPT)

The hands-on exercise with the Penning trap at CARIBU will provide participants with the opportunity of learning a new technique that is now being used to make precise mass measurements of radioactive isotopes: the phase-imaging ion-cyclotron-resonance technique (PI-ICR). By imaging the orbital motion of the ions in a Penning trap, the characteristic frequencies can be measured very precisely and from that the masses can be determined. During the Exotic Beam Summer School, participants will become familiar with the PI-ICR technique and will use this technique to obtain precise mass measurements and identify the constituents of a CARIBU beam.

2. Identification of reaction products with the Fragment Mass Analyzer (FMA)

The Argonne Fragment Analyzer (FMA) separates products of nuclear reactions from a primary beam and disperses them according to their mass over charge ratio. In this exercise products of nuclear reactions induced by a heavy-ion beam from ATLAS impinging on a thin target will be detected at the FMA focal plane. A position-sensitive transmission Parallel-Grid Avalanche Counter (PGAC) will be used to measure position of the reaction products in the FMA focal plane. The reaction products will be stopped in a segmented ionization chamber placed behind the PGAC and their energy loss and energy will be measured. Based on these measurements the atomic mass and the atomic number of the reaction products will be deduced. In addition, a Ge detector will be placed at the target position and coincidences between prompt gamma rays and the recoiling nuclei will be measured to assign the gamma rays to individual reaction channels.

3. Gamma-ray detection techniques with digital Gammasphere and GRETINA

The Gammasphere Ge-detector array will be used to detect beta-delayed gamma rays. Digital pulse analysis will be used to determine gamma ray energies and times. A nuclear level scheme will be constructed based on gamma-gamma coincidence measurements. The gamma-ray signal decomposition and position determination will be demonstrated using a GRETINA gamma-ray tracking module.

4. Characterization of charged particles using HELIcal Orbit Spectrometer (HELIOS)

Students will be able to calculate various properties (target-detector distance, cyclotron period, etc...) key to the use of the Helical Orbit Spectrometer - HELIOS - in direct reaction studies in inverse kinematics. Then they will have the opportunity to set up the target position and alignments inside the solenoid magnet in order to test their calculations through the collection of alpha-source data. Also, they can learn about a digital data acquisition and processing such data.

5. Measurement of the Bragg curve using the MUlti-Sampling Ionization Chamber (MUSIC)

The Multi-Sampling Ionization Chamber detector (MUSIC) is a highly efficient "active target" system that allows the study of nuclear reactions (e.g. (a,p), (a,n), (p,a), fusion,..) covering a large energy range using a single beam energy. The hands-on activities with MUSIC will give the students the opportunity to see real-time data collection of the Bragg curve of alpha particles with different energies as they travel through a gas medium at different pressures. The students will use these data and energy-loss tables from the literature to calculate the energy of the alpha particles and to predict the pressure which is required to sto p the alphas at different positions inside the detector. The students will then have the opportunity to change the pressure of the gas in the detector and verify their energy loss calculations.

6. Target preparation techniques in the Traget Laboratory

A brief introduction to the Physics Division Target Facilities will be presented. Hands on activities will include an exhibition of Physical Vapor Deposition (PVD) as a method of target production using one of the vacuum evaporators. Next, the students will try their hands at the floating technique used to mount the ultra-thin foils onto ATLAS target frames.