Treatment of Coulomb collisions within the beam requires consideration of both large and small angle scattering. Such collisions lead to the Touschek effect and Intrabeam Scattering (IBS). The Touschek effect refers to particle loss as a result of a single collision, where only transfer from the transverse direction into longitudinal plays a role. It is important to consider this effect for ERL design to have an appropriate choice of collimation system. The IBS is a diffusion process which leads to changes of beam distribution but does not necessarily result in a beam loss. Evaluation of IBS in ERLs, where beam distribution is non-Gaussian, requires special treatment. Here we describe the IBS and Touschek effects with application to ERLs.

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Treatment of Coulomb collisions within the beam requires consideration of both large and small angle scattering. Such collisions lead to the Touschek effect and Intrabeam Scattering (IBS). The Touschek effect refers to particle loss as a result of a single collision, where only transfer from the transverse direction into longitudinal plays a role. It is important to consider this effect for ERL design to have an appropriate choice of collimation system. The IBS is a diffusion process which leads to changes of beam distribution but does not necessarily result in a beam loss. Evaluation of IBS in ERLs, where beam distribution is non-Gaussian, requires special treatment. Here we describe the IBS and Touschek effects with application to ERLs. In circular accelerators both the Touschek effect and IBS were found important. The generalized formulas for Touschek calculations are available and are already being used in advanced tracking simulations of several ERL-based projects. The IBS (which is diffusion due to multiple Coulomb scattering) is not expected to cause any significant effect on beam distribution in ERLs, unless one considers very long transport of high-brightness beams at low energies. Both large and small-angle Coulomb scattering can contribute to halo formation in future ERLs …

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Wake fields in high-current ERLs can cause significant beam quality degradations. Here we summarize effects of coherent synchrotron radiation, resistive wall, accelerating cavities and wall roughness for ERL parameters of the eRHIC project. A possibility of compensation of such correlated energy spread is also presented. An emphasis in the discussion is made on the suppression of coherent synchrotron radiation due to shielding and a possible reduction of wall roughness effects for realistic surfaces.

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Wake fields in high-current ERLs can cause significant beam quality degradations. Here we summarize effects of coherent synchrotron radiation, resistive wall, accelerating cavities and wall roughness for ERL parameters of the eRHIC project. A possibility of compensation of such correlated energy spread is also presented. An emphasis in the discussion is made on the suppression of coherent synchrotron radiation due to shielding and a possible reduction of wall roughness effects for realistic surfaces. In this report we discuss the wake fields with a focus on their effect on the energy spread of the beam. Other effects of wake fields are addressed elsewhere. An energy spread builds up during a pass though a very long beam transport in the eRHIC ERL under design. Such energy spread become important when beam is decelerated to low energy, and needs to be corrected. Several effects, such as Coherent Synchrotron Radiation (CSR), Resistive Wall (RW), accelerating RF cavities (RF) and Wall Roughness (WR) were considered. In this paper, we briefly summarize major contributions to energy spread from the wake fields for eRHIC parameters, and present possible energy spread compensation for decelerated beam. In the rest of the report we discuss effects which we believe are …

Photograph of Fabiana González-Cobos (right) and Kathryn Supina (left) performing "Pur ti miro" at an event titled "Opera's Greatest Hits: A Gala Concert" held at Winspear Hall. González-Cobos is standing behind Supina with her hands on Supina's shoulders.

Photograph of Jennifer Youngs performing "Regnava nel silenzio" at an event titled "Opera's Greatest Hits: A Gala Concert" held at Winspear Hall. The University of North Texas Symphony Orchestra is performing in the background while Youngs sings.

Photograph of students performing "Anvil Chorus" at an event titled "Opera's Greatest Hits: A Gala Concert" held at Winspear Hall. Performers are standing in pairs as the University of North Texas Symphony Orchestra plays in the background.

Daily newspaper from Sweetwater, Texas that includes local, state, and national news along with advertising.

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Working group 4 was charged with presentations and discussions on instrumentation and controls with regards to Energy Recovery Linacs (ERL). There were 4 sessions spanning 3.5 hours in which 7 talks were delivered, the first being an invited plenary presentation. The time allotted for each talk was limited to 20-25 minutes in order to allow 5-10 minutes for discussion. Most of the talks were held in joint session with working group 5 (Unwanted Beam Loss). This format was effective for the purpose of this workshop. A final series of discussion sessions were also held with working group 5. Summary of the working group 4 activities, presented in the closing plenary session. We had a plenary presentation on operational performance, experience, and future plans at the existing ERL injector prototype at Cornell. This included instrumentation data, controls system configurations, as well as description of future needs. This was followed by four talks from KEK and RIKEN/SPring-8 that described electron beam instrumentation already in use or under development that can be applied to ERL facilities. The final talks described the ERLs under construction at KEK and BNL. The format of having joint sessions with working group 5 was beneficial as there were …

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.

Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.

Semi-weekly newspaper from Livingston, Texas that includes local, state and national news along with advertising.

Semiweekly newspaper from Carthage, Texas that includes local, state, and national news along with advertising.

Newspaper from Berkeley, California that includes news and information about the Black Panther Party.

Photograph of Fabiana B. González-Cobos (left) and Kathryn Supina (right) performing "Pur ti miro" at an event titled "Opera's Greatest Hits: A Gala Concert" held at Winspear Hall. The performers are facing each other with their arms around each other.

Photograph of Nan Qin performing "Madamina, il catalogo è questo" at an event titled "Opera's Greatest Hits: A Gala Concert" held at Winspear Hall. The University of North Texas Symphony Orchestra is performing in the background while Qin sings.

Photograph of Jennifer Youngs performing "Regnava nel silenzio" at an event titled "Opera's Greatest Hits: A Gala Concert" held at Winspear Hall. The University of North Texas Symphony Orchestra is performing in the background while Youngs sings.