# Presentation: 170021

## NuMI Magnet Power Supply System 

**WBS 1.1.3  *****Power Supply System***
**Level 3 Manager**
***Nancy Grossman***** **
***FNAL***
**July 11, 2001**

## Outline

**Overview and Specifications (Nancy Grossman, 20’)**
- Conventional Power Supplies and Cables (PS)
- Kicker Power Supply and Cables (PS)
_**Status of Refurbished PS (Steve Hays, 30’)**_
_**Status of Kicker PS (Chris Jensen, 30’)**_
_**Status of Cooling System for PS (Dave Pushka, 30’)**_
**Cost/Schedule/Concerns (Nancy Grossman, 10’)**

## Overview of the Magnet Power Supply System

**Conventional Power Supplies (PS) (all existing PS’s to be refurbished or bought from FNAL spares inventory; Steve Hays, Bob Ducar)**
**Ten 500 KW PS **
**1 Main Ring PS **
**Three 240 KW PS (one used at MI8 for testing horns)**
**Ten 20 KW PS**
**PS for 12 Main Injector trim magnets**
**1 Kicker PS (to be designed, built and tested; Chris Jensen)**
**AC (480 panel to PS) and DC Power Supply Cables and Connectors (Steve Hays, Bob Ducar)**
**All large power supplies are ramped.**
**All quad and trim PS’s are DC and have their own PS.**

## Refurbished Magnet Power SuppliesSpecifications

_**Conventional Power Supplies and Cables (Steve Hays, Bob Ducar)**_
**Must provide reliable, stable power to beamline elements while minimizing power consumption.  **
**The NuMI facility is expected to be operational for of order ten years, and the power supply system has been designed with this in mind.  **
**Power supplies must accommodate a repetition period of 1.9 seconds (~1 msec flatop).**
- Want PS to stabilize at flatop, read it to check current and have time to still extract.
**Personnel safety must be assured from possible electrical, mechanical and radiological hazards during installation and operations. **
**Voltage and current requirements for the various beamline elements determine what power supplies and cables will be needed.  **
- _Table_ summarizes these requirements and indicates the chosen power supply for each case.
**For beam tuning and focusing, each trim and quadropole magnet has its own power supply.  **
**Bend circuits use several 500 kW supplies in series (or for the V105 circuit a Main Ring Power Supply) in order to obtain the desired voltage levels.**

## Refurbished Magnet Power Supplies:MI60

## Technical Progress & Status: HV101 PS at MI60

## Technical Progress & Status:  V100, LAM60 and Quad PS MI60

## Refurbished Magnet Power Supplies:MI62

## Refurbished Magnet Power Supplies:Target Hall Service Building

## Refurbished Magnet Power Supply Regulation

**Power supply regulation “requirements” shown below**
- Groundwater irradiation
- Stability of beam on target
**720 Hz line ripple effect on the PS currents is shown in the table below.**
- Need filters on all bend strings

## Refurbished Magnet Power Supply Regulation

**Simulations were run for the NuMI V105 string, assuming a constant reference voltage.**
** ****5% change in line voltage was easily corrected for at the level of ~25 ppm  **
**        ****with standard voltage regulation. (most variation one would expect)**
** ****5% load change (resistance) gave a 240 ppm current variation.**
- Corresponds to about a 100 C change in the copper in the magnet or the LCW changing 150C
- Need additional regulation.
**HOLEC transductor ($5K/string) & Special FNAL regulation electronics ($5K/string)**
**Both are designed and installed in the Main Injector**
**This combination of electronics would give another factor of 2         120 ppm**

## Refurbished Magnet Power Supply Regulation

**Three strings are still above the required specifications. **
**So now what?**

## Refurbished Magnet Power Supply Regulation

_**Bandwidth**_
**Each string will be tuned for maximum bandwidth.**
- 20 Hz is assumed in the previous calculations, 40 Hz may achieved (but not guaranteed).
- Gives a factor of 2 in current stability.
_**Auto-tune**_
**Load changes are typically slow changes and thus Auto-tune can correct for these.**
**One could then argue why do you need the extra power supply regulation too?**
- Auto-tune does not always work.
**Needs beam and working beam position monitors to work.**
**Assumes next beam pulse like the previous one.**
- Experience at FNAL where significant beam control is needed says do both.
- Since the power supply regulation is also driven some by groundwater concerns, we want something that is always working.

## Refurbished Magnet Power Supply Regulation

**NuMI bend string  power supply regulation levels will be achieved by:**
- Filters on all 7 strings.
- HOLEC and FNAL Electronics on all 7 strings.
- Auto-tune.
- Tuning for maximum bandwidth.
**Quadropole power supplies (20 KW  PEI’s):**
- Standard regulation is at +/- 0.05% of the maximum current (100 or 200 amps)
**Corresponds to up to +/-0.44% variation in operating current.**
- Believed to be sufficient.
**Main Injector Trim Magnet  power supplies:**
- Standard regulation is at +/- 0.1% of the maximum current (15 amps)
- Believed to be sufficient.

## Refurbished Magnet Power SuppliesStatus

_**Conventional Power Supplies and Cables (Steve Hays, Bob Ducar)**_
**MI60 Power Supply Cables:**
- DC cable pulls complete (except kicker PS), including termination on PS side.
- AC cabling of power supplies is complete (except kicker PS).
**MI62 Power Supply Cables:**
- AC cabling done except for Main Ring PS.
**Conventional Power Supplies:**
- 9 refurbished, 4 for Target Hall still need to be refurbished.
- Ones in existing construction are also in place (except MR PS and Kicker PS).
**6 large power supplies, 7 quads and 12 trim power supplies.**
- Testing of the PS will begin shortly.
- Filter chokes and the Main Ring PS need to be installed (not behind schedule).
- Scheduled to happen soon.
- All ahead of schedule and within budget.

## Specifications for the Extraction Kicker

- Minimum Integrated Field: 	2.24 kG - m
- Kick Angle @ 120 GeV: 		563 μrad to inside of ring
- Field Rise Time (1%-99%): 	1.30 μs
- Field Fall Time: 		N/A
- Field Flattop Time: 		9.78 μs minimum( 6 batches)
- Flattop During Pulse:		± 1%
- Flattop pulse to pulse:		± 1%
- Repetition Rate:		1.9 seconds
- Required Charging Time:		1.5 seconds
- Magnet Location: Immediately Downstream Q602
- Power Supply Location: MI-60 Service Building, South Power Supply Room

## Kicker Power Supply

_**Kicker Power Supply - based on MI-52 kicker design (Chris Jensen)**_
- Design modifications to change polarity of supply. (Significant design effort.)
- Pulse Forming Network driving two (or three series/parallel) magnets in parallel.
- PFN has 32 sections, 33 nF/section, 825 nH/section, 46 kV at minimum kick
- Increase coupling of Pulse Forming Network (versus MI-52)
- Longer lifetime capacitors for PFN (versus MI-52)

## Kicker Power Supply

**Work on the charging power supply specification is in progress.**
**Drafting is in progress:**
- Design is ~40% complete
- Swtich tube enclosure 50% complete.
**Some long lead time parts ordered:**
- End of  line clipper diodes
- Controls parts
**Kicker controls are 30% complete.**
_**Much of the design is delayed due to magnet design questions (ceramic tube)**_
_**Much of the kicker construction, machining and purchase orders will be delayed to FY2003.**_**  **
- Due to funding profile with re-baseline
- Still allows several months of float in the kicker construction, testing and installation.

## Other Presentations

**Overview and Specifications (Nancy Grossman, 20’)**
- Conventional Power Supplies and Cables (PS)
- Kicker Power Supply and Cables (PS)
_**Status of Refurbished PS (Steve Hays, 30’)**_
_**Status of Kicker PS (Chris Jensen, 30’)**_
_**Status of Cooling System for PS (Dave Pushka, 30’)**_
**Cost/Schedule/Concerns (Nancy Grossman, 10’)**

## Costs

**Refurbished Power Supply & Cable Costs**
- Total Budget: ~$900K
- Percent Complete:~48%
**Cables, MR PS, regulation/filters, testing**
**Kicker Power Supply and Cables**
- Based on 2 magnet design....
- Total Budget: ~$534K
- Percent Complete: ~40%
- Need new cost estimate based on 3 magnet design - in progress.

## Schedule & Milestones

## Concerns/Summary

**Refurbishing of conventional PS and installation of their AC and DC cables is ahead of schedule and within budget.**
- Regulation requirements are tight, but doable
- Concerned about integration of the power supply regulation/readout into the NuMI Beam Permit System
**Kicker Magnet Power Supply**
- On schedule and budget so far, but...
- Will the magnet design change to 3 magnets versus two due to having to use a shorter ceramic tube?
**Cost/schedule implications of that are in progress and nearly complete.**