To provide high quality electron bunches for linear accelerators used in free electron lasers and particle colliders, RF gun cavities operate with extreme electric fields, resulting in a high pulsed RF power. The main L-band superconducting linacs of such facilities also require a long RF pulse length, resulting in a high average dissipated RF power in the gun cavity. The newly developed cavity based on the proven advantages of the existing DESY RF gun cavities, underwent significant changes. The shape of the cells is optimized to reduce the maximal surface electric field and RF loss power. Furthermore, the cavity is equipped with an RF probe to measure the field amplitude and phase. The elaborated cooling circuit design results in a lower temperature rise on the cavity RF surface and permits higher dissipated RF power. The paper presents the main solutions and results of the cavity design.

Design of an L-band normally conducting RF gun cavity for high peak and average RF power

The normal conducting booster cavity is intended to increase the electron bunch energy in the Photo Injector Test (DESY, Zeuthen) stage 2 experiments [1]. The normal conducting cavity is selected due to infrastructure particularities in DESy Zeuthen. The L-band cavity is designed to provide the accelerating gradient up to 14 MV/m with the total input rf power up to 8.6 MW, rf pulse length up to 900 mks and repetition rate 5 Hz. The multi-cell cavity is based on the CDS compensated accelerating structure with the improved coupling coefficient value. The main design ideas and decisions are described briefly together with cavity parameters - rf properties, cooling and pumping circuits.

/pdf/desgign-parameters-of-the-normal-conducting-booster-cavity-xf0snfz9v2.pdf

Desgign parameters of the normal conducting booster cavity for the pitz-2 test stand

In some special parts of present projects, such as X-FEL and ILC, normal conducting cavities are applied, operating with high electric and magnetic fields. RF gun cavities with an electric field up to 60 MV m at the photo cathode are now under development. Capture cavities in the ILC positron source should operate with an accelerating gradient of up to 15 MV m , practically the same value (14 MV m ), as for the CDS booster cavity in the Photo Injector Test Facility at DESY in Zeuthen (PITZ). Such operating conditions, together with long (∼ 1ms) RF pulse, lead to the apparent cavity pulsed heating effect. In this report we describe the procedure and results of pulsed heating effect simulations in L-band cavities, operating with high pulsed RF loss density and long RF pulse.

https://flash.desy.de/sites/site_vuvfel/content/e403/e1642/e1849/e1933/infoboxContent2144/tesla-fel2007-04.pdf

Pulsed RF heating simulations in normal-conducting L-band cavities.

At DESY normal conducting RF Gun cavities operate with electric fields at the cathode of Ec = 40MV/m or Ec = 60MV/m and a pulse input RF power of Pi ∼ 3.2MW and Pi ∼ 6.8MW , respectively. In combination with a long RF pulse of τ ∼ 1ms and 10Hz repetition rate it results in average dissipated RF power of Pa = 0.01Pi, equal to Pa ∼ 32kW and Pa ∼ 68kW . Taking into account the cavity dimensions, the average RF power of Pa ∼ 68kW corresponds to a heat load of ∼ 300 kW m . To remove such a high heat value from the cavity body, an advanced cooling circuit is required. The cooling circuit capability depends on the cooling channel design and the water flow parameters and finally defines the maximal possible dissipated RF power, which can be removed from the cavity and, hence, limiting the cavity duty factor. In this report we describe a cooling circuit study for DESY RF Gun cavities N2, N3 with the aim to optimize the water flow distributions for a maximal dissipated RF power. For Gun 4, with independent cooling channels, the goal of the study is to investigate the flexibility of such a design decision.

https://flash.desy.de/sites/site_vuvfel/content/e403/e1642/e2308/e2310/infoboxContent2318/TESLA-FEL2008-02.pdf

RF gun cavities cooling regime study

Due to dispersion properties, 4-vane RFQ cavity without resonant coupling is a thermally unstable structure. With deterioration of balance for local detuning, especially near cavity ends, there is a possibility for runaway in the field distribution and related thermal-stress effects. It can, in principle, finish with irreversible plastic deformations and cavity frequency shift. Both the increment and the threshold of instability are proportional to the average dissipated RF power. This possibility increases for long RFQ cavities. Also particularities for the cavity ends design are important. Some general features of this effect are discussed and illustrated with simulations.

/pdf/one-aspect-of-thermal-stability-for-4-vane-rfq-operation-2jn19azlxg.pdf

One aspect of thermal stability for 4-vane rfq operation with high heat loading

The design of high intensity proton linacs with high RF duty factor or cw operation requires critical evaluation of a 3-D coupled RF-thermal- structural-RF analysis for a normal conducting accelerating structure. The problem of heat removal from a normal conducting proton linac structure sets a limit on the operational RF duty factor. Therefore it is very important for a normal conducting high current proton linac structure to be analyzed as precise as possible for structural stability if it has to be operated at mush higher heat loading. A detailed procedure has been developed by performing a series of coupled analysis of rf-thermal and structural behavior using a single Finite Element software (ANSYS) environment. The appropriate constrain conditions in the structural analysis are of primary importance, a special procedure to establish the correct displacement values for the equilibrium conditions for the longitudinal structural expansion are also explained. The possible shift in the RF frequency due to non-uniform heating of the structure is also described. The particularities of the transient thermal behavior of the structure are discussed.

/pdf/the-complete-3-d-coupled-rf-thermal-structural-rf-analysis-4o7p9vl36h.pdf

The complete 3-d coupled rf-thermal-structural-rf analysis procedure for a normal conducting accelerating structure for high intensity hadron linac

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

M. Ikegami

Author Tools

Chat about Author

Papers

The complete 3-d coupled rf-thermal-structural-rf analysis procedure for a normal conducting accelerating structure for high intensity hadron linac