# Presentation: 172067

**SNS D-plate System **
**Preliminary Design Review – **
**Physics, Requirements, and Interfaces**
**Los Alamos, July 18, 2001**
**by Michael Plum**

## D-plate components

## D-plate isometric image

## D-plate instrumentation

**Beam current measurement.**
**Beam position measurement (3 ea.).**
- Also time of flight energy measurement.
**Video profile and position.**
**Wire scanner profile (3 planes).**
**Slit and collector emittance measurement (2 planes).**
**Faraday Cup / energy degrader.**
**Halo scraper.**

## D-plate usage scenarios

**Set DTL tank 1 phase and amplitude.**
**Measure properties of beam exiting DTL tank 1.**
- Beam energy by time of flight between two identical BPMs.
- E = mc2 (*)3 (c/L) t gives 26 keV accuracy, or 0.5% tank 1 energy gain.
- Beam profile measurements with wire scanner, phosphor screen, and emittance gear.
- Beam emittance measurement with slit and collector (x and y).
- Beam current with toroid.
**Accommodate DTL tank 1 aperture scans.**
**Test DTL diagnostics (WS, CM, ED/FC) and steering magnets.**
**Check MEBT to Tank 1 matching.**
**DTL transmission measurement.**
**Beam stop for full power tests of front end systems plus DTL tank 1.**
**Tests of methods to improve MEBT beam quality.**

## D-plate usage scenarios (cont.)

- Example of PARMILA model of LANSCE DTL tank 2 phase scan.
- (From L. Rybarcyk)

**Set amplitude**

**Set phase**

## Beam modes and parameters

**The D-plate must function under a variety of beam parameters, depending on the beam mode. **
*Commissioning mode beam parameters*
*Nominal beam parameters during normal operation*
*Troubleshooting beam parameters*
- Same as commissioning beam parameters.
*Beam development beam parameters*
- Same as commissioning beam parameters.

## Beam parameters for commissioning

| MEBT commissioning | 1 – 10 Hz; 1 to a few minipulses or 10 – 100 us overall pulse length, 20 – 30 us ramp; 10 to 60 mA peak (as measured during mini pulse); 300 ns to unchopped mini pulses. |
| --- | --- |
| DTL commissioning | 1 – 10 Hz; 1 to a few minipulses or 50 us overall pulse length; 20 – 30 us ramp, 10 to 60 mA peak (as measured during mini pulse); 300 ns to unchopped mini pulses. |
| CCL commissioning
 | 1 Hz, 1 to a few minipulses or 50 us overall pulse length, 20 – 30 us ramp; 10 to 60 mA peak (as measured during mini pulse); 300 ns to unchopped mini pulses. |
| SCL commissioning
 | 1 Hz; 1 to a few minipulses or 100 us overall pulse length, 100 us ramp; 10 to 60 mA peak (as measured during mini pulse; 300 ns to unchopped mini pulses. |
| Ring commissioning
 | 1 – 10 Hz, 1 mini pulse, 10 to 60 mA peak (as measured during mini pulse), 300 to 700 ns long single mini pulses. |

- * All beams are H–

## Beam parameters for normal operation

| Peak beam current | 38 mA averaged over 690 ns mini pulse (26 mA avg.). (Was 52 mA in original design.) |
| --- | --- |
| Mini pulse period | ~ 950 ns |
| Mini pulses per pulse | ~ 1000 |
| Pulse length | 1 ms |
| Rep rate | 60 Hz |
| Beam sizes | MEBT:	x = 1.3 – 3.4 mm, y = 1.0 – 2.8 mm (1 )
DTL:	x = 1.8 – 2.7 mm, y = 1.0 – 2.7 mm (1 )
   Extreme sizes are about sqrt(5) times larger |

## D-plate system requirements

- Requirements as defined in Design Criteria Document SNS_104050000_DC0001_R00; April 30, 2001.

- Note: SNS parameters list, SNS-100000000-PL0001-R05, May 2001, lowers the peak current to 38 mA, and the average current to 26 mA. (11.7 kW)

## D-plate system requirements (cont.)

**DTL tank 1 phase and amplitude set point requirements are ****±0.5****o**** and ±0.5% (WBS 1.4 SRD, WBS 1.4.2 DCD).**
- Time of flight system accuracy is ±0.5%.

## D-plate design issues

**The D-plate is the last point in the linac where the machine can be run at full nominal beam current until spallation target is commissioned.**
**Need a system that will insure average beam current is kept within limits. 60 Hz, 1 ms pulse length, unchopped beam, will exceed the operating envelope.**
- Plan to use the machine protection system and a the current monitor system to limit beam power.
**Emittance measurement will use electronics now being developed at LBL.**
**To reduce costs we are utilizing as much used equipment as possible. **

## Other reviews relevant to the D-plate 

**BPMs – PDR held Feb. 2001.**
**WS – PDR held Jul. 2001.**
**CM – PDR not yet scheduled.**
**ED/FC – PDR not yet scheduled.**
**Systems for which we have no plans for a separate PDR:**
- Phosphor screen profile measurement.
- Slit and collector emittance measurement (but there may be one for the MEBT emittance measurement).
- Beam stop (but there will be a safety review).

## D-plate optics

- Plot of rms beam size vs. distance for the **emittance tune**. The solid line and circles show the horizontal rms beam size, and the dotted line and triangles show the vertical rms beam size.

- Plot of rms beam size vs. distance for the **beam stop tune**. The solid line and circles show the horizontal rms beam size, and the dotted line and triangles show the vertical rms beam size.

## Interfaces

- Interface to
- DTL tank 1

- Interface with DTL
- vacuum and water system

## Interfaces (cont.)

**The electrical interface occurs at the rack (except for pickup cables) where the electronics are mounted. I/O from the RTDL / event link, Ethernet, MPS, 120 Vac on/off.**

- Network attached
- instrument

- Pickup

- IP

- RTDL

- Event link

- Ethernet
- Channel Access

- Machine protect

- Application programs

- 120 Vac on/off

- Control system

## System responsibilities

**Saeed Assadi, responsible  for ORNL portion of project.**
- Acceptance of D-plate and integration into SNS project.
- Oversight of installation and testing.
**Mike Plum, responsible for LANL portion of project.**
- Delivery of D-plate to ORNL.
**Responsible parties will work together to develop a handoff strategy and agree on the criteria that define a successful system handoff.**

## Schedule

**The MEBT will be delivered to ORNL in the summer of 2002.**
**DTL tank 1 installation complete and ready for D-plate installation 26/Nov/01.  **
**The D-plate will be delivered to ORNL in the fall of 2002. **

## Summary

**We are on track to deliver, on schedule, a D-plate that meets all target requirements.**