# Presentation: 688892

## MTA RF Status01/31/ 2007NF&MCC MeetingUCLA

**A. Moretti**

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## Purpose of the 805 and 201 MHz testing in the MTA

**The 805 MHz testing is a continuation of the 805 MHz testing conducted in Lab G with the addition of a 201 MHz  test facility. The purpose being:**
**Study  Breakdown Limit of Vacuum Cavities.**
**Study Dark Current  and X-Ray emissions at high gradient**
**Study the effect of High Magnetic on Breakdown, Dark Current and X-Ray emissions**
**Study Fast Muon Detectors in this environment.**
**Study in the Button cavity methods to reduce dark current with different materials, coatings and processing using small insertable samples ( Buttons).**
**   **

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## Description of the Experimental Setup

**                     ****Linac Type Modulator and Controls**
** ****12 MW 805 MHz Klystron system and 100 m **
**     ****Waveguide run and 5 MW 201 MHz system with 120 m**
**      ****0.23 m Coaxial cable run.**
** ****Cavity High Vacuum  System **
** ****Cavity cooling Water System**
** ****5.0 T Solenoid**
** ****Support Cryogenic System**
** ****X-Ray Shielded Cave and X-Ray monitors**
**     ****Surrounding the cavity.**
** ****Interlocked RF with Sparking, Cavity Vacuum**
**      ****and External X-Ray level.**
** ****Clean room for preparing samples.**

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## Experimental Layout

**Detector**
**   ****# 1**

**805 MHz Cavity**

**201 MHz Cavity**

**5 T Solenoid**

**2.73 m**

**1.38 m**

**Window**

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

##  805 MHz Cavity under Test

-  805 MHz Cavity under Test

**Testing Curved Be Windows coated with TiN.**
**Flat windows were  Freq unstable because of EM impulse.**
**Frequency instability stopped by Eddy current brake in Magnetic Field.**
**Curved window have been shown to be  frequency stable without magnetic field.**

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## Button Cavity to continue the 805 MHz Study with different Materials and Coatings.

**Vacuumed Sealed Sample Holder**

**Sample Button Material**

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## LBL 201 MHz 

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## Picture of MTA Hall and 201 MHz Cavity

- Current Picture of the MTA Hall showing the 5 T magnet in the foreground and the waveguide RF power input to 805 MHz cavity in back ground is the 201 MHz cavity.

- 201 MHz cavity during preparation for installation in Aug 05.

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## 201 MHz 5 MW Amplifier and the 805 MHz 12 MW Klystron 

**201 MHz 5 MW Amplifier**

**805 MHz 12 MW Klystron System**

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## First RF 805 MHz Commissioning without Magnetic Field Last March

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## First Radiation Measurement with Magnetic Field compared to No Field Data

**March 06, Results. Safe     E Field Limit ~ 16 MV/m Detector Distance=1.34 m**

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## Nov. 06 Results: Electric field limit at 2.5 T in the LBLSingle Cell Cavity with Curve Be Windows coated with TiN

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## Latest Electric field limit Data at 2.5 T and 1.25 T in the LBLSingle Cell Cavity with Curve Be Windows coated with TiN

**Asymptotic Gradient  limit line at 1.25 T**

**2.5 T Data**

**RF Conditioning without Magnetic Field **

**The **_**Asymptotic limit line**_** shown indicates the continuous Gradient sparking limit. In all the cases studied including Lab G this line as predicted the Gradient Limit for the cases under Study.**
**For the 1.25 T case the   Save operating limit has been shown to be**
**         ****20 MV/m**** **

**1.25 T Data**

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## Comparison of Lab G Results with the MTA Data

**MTA Result ~ 16 MV/m**

**MTA 1.25 T  Result Jan. 07**

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## CERN DC Spark Breakdown Compared to 805 MHz Cavity 

**CERN DC Spark Breakdown Compared to 805 MHz Cavity **

- Sparking History of 805 MHz Cavity

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007

## Conclusions and future plans

**Results of Lab G have been verified with the curved Be windows in March 06 and in Nov 06 at 805 MHz in the MTA at 2.5 T and In January 07 at 1.25 T.**
**We need to continue the study to determine the mechanism for the enhancement of Dark Current in Large Magnetic fields: does it increase the number of emitters, the electric enhancement factor, or both? **
**The button cavity will be used to study these and other questions: materials, coatings, etc. Plans are underway to install the Button cavity and begin these studies.**
**Studies on the 201 MHz cavity are continuing and plans are underway to move it close to magnet to be in as high as fringe field as possible.**

- A. Moretti, NF&MCC Meeting, UCLA

- 01/31/2007