# Presentation: 219033

## MuCool / Linac Diagnostic Beamline and MTA facility: 

- External Beams Dept.
- C. Johnstone, + others
- Review
-  Nov. 30, 2005

## Purpose:

- test the basic techniques and components proposed for muon ionization cooling and
- provide accurate measurements of linac beam properties – important for future, stable high-intensity running of the downstream accelerators.

## Description:

- The new beamline and facility consists of
- 15 Hz pulsed-magnetic extraction system which diverts an entire Linac macropulse into the new beamline
- An ~50 m long beamline which feeds and ends in experiments housed in a 20’ x 40’ hall; the Mucool Test Area (MTA)
- Using civil construction and resources that remain from the 400-MeV Linac Upgrade; this project is considerably economical.
- The experimental hall is shielded and separated from the Linac by 12’ of concrete blocks— the beamline penetrates through these shield blocks to the hall
- The new facility is capable of:
- Accepting full Linac beam intensity (1.6 x 1013 protons @ 15 Hz) to within the radiological limits imposed by the current state of shielding and radiological controls

## MTA facility:  Plan View

## Low-loss Beam Extraction from Linac

- Extraction to MTA
- Begins upstream and continues downstream of 400-MeV chopper to contain H- magnetic stripping losses to 10-4 level.
- Requires 10” movement of Q74 upstream*
- The entire Linac macropulse is extracted (the length of the macropulse may be varied from 2-50 by the 750-keV chopper.
- Pulsed extraction magnets:
- Pulsed extraction magnets: two “C” magnets
- One 3 magnet upstream and one 7.5 magnet downstream; single power supply for both
- >1” of clearance/no conflicts with 400-MeV line
- No 400-MeV vacuum interruption for installation/removal
- Design is complete; bids are in; awaiting final division budgets

- *kicking beam through Q74 causes a large displacement in the 2” Linac beampipe with accompanying high losses.

## 400 MeV Linac Enclosure

**~2m Extraction Drifts**

**Ramp trajectories**

**Ramp enclosure wall**

## H- Extraction Requirements

**Beam entering ramp requires ~30******** of bend relative to Linac**
**Dipole field strengths**
- 7kG to avoid stripping H-,
- upstream of chopper, ~6kG (Chopper is highly sensitive to electrons and sparking)
**First component to clear is Q2**
- Controls beam separation to Booster/diagnostic line
- Cannot be moved; tricky to align
- Requires 11” to clear manifolding, 13-15” beam center to center relative to transfer line
**Next element to clear is lambertson**
- Dipole (CR) conveniently fits next to transfer line between Q2 and lambertson
- If CR dipoles are used (10 max) another one is required to avoid enclosure corner, 45 total is required for ramp curvature and align beam parallel with the experimental hall enclosure.

## Linac modifications: Q74 moves ~10’ upstream

**Quad to be moved**

**BLD – will be removed to make space for quad**

## Pulsed Extraction System: Two C Magnets

**Two C magnet: 10”, 25” long, 6.2 kG, 3********, 7.5******** bends**

**Chopper**

## Extracted Beam trajectories

## Critical Path: C magnets 

**   ****76.281”**
**(1.9375 m)**

- sssssssssssssssssssssss

- z

- z

** ****10”**
**0.254 m**
**IRON**

**   ****Tube ******** 2” ******
**0.0625” WALL 304 SS**
****** ****1.5” Beam Tube ******

- Z

**16.75” slot**
**(0.4254 m)**
**(17.8” total **
**flange to**
**quad steel)**

**QUADRUPOLE**

**3.005******

** **
**  ****4.563”**
**(0.1159 m)**

**   ****25.866”**
**(0.6570 m)**
**  ****IRON**

- z

**4.869”**
**(0.1126 m)**

**    ****TUBE 304 SS ******** 3.25”**
**        ****0.0625” WALL**

**R1.625”**
**(0.04128 )**

**1.949’ (0.0495 m)**

**4.618”**
**(0.1173 m)**

- X

**2.125” min **

**(0.0540 m)**

- See example coil and lamination details  in text + tables

**2” schedule **
**to pipe **

**   ****1.850”**
**(0.0470 m)**

**Example coil**
**(0.4096” Cu):**

**Gap: 2.000”**

**~1/16” spacing between beam tubes**
**@entrance to magnet**

- Beam tubes in longer magnet

## Diagnostic Line Design - 

- New design incorporates
- 10 m straight for transverse emittance measurements of linac beam
- 50 cm low beta waist at center of straight
- Order of magnitude change in beam size
- Access to low beta focus point
- Dispersion suppression
- Inexpensive straight bore through shield blocks
- Simple, stable match to linac based on linac FODO cells (~90)
- High (~7m) dispersion point for momentum-spread measurement

## Optical functions

## Half-width beam size:

- MW1

- MW2

- MW3

- Experimental Hall

- Shield blocks

## Layout, plan view

- Shield blocks

## Operational details of Diagnostic Tune

- Minimum beam stay clear –
- 0.3” (8mm) in upstream 2” chopper mating flange and triplet quadrupoles based on 10  mm-mr linac emitance.
- Dispersion suppression can be checked and tuned by :
- varying linac output energy and varying last CR dipole strength
- Beam will be “steered” into hall using trims after the diagnostic straight
- Low-beta waist can be adjusted and focused onto the second multiwire (just downstream of shield blocks)
- Using the quad low-beta triplet
- Critical Devices:
- Pulsed extraction magnets
- Beam stop upstream and downstream of shield blocks
- Occupancy and radiological controls
- Beam stops provide unlimited occupancy in experimental hall
- Postings, fencing, eberm module will allow us to run at  ~1 Hz and full linac intensity
- Pulsed power supply will be hard-wired to 1 Hz.

## Low-loss beam tune for MTA running

- Beamline can be re-tuned for MTA experiments to achieve the lowest-loss optics. One example is given below with momentum spread included. The peak beam envelope is reduced by 1 cm in the half width (2 cm full width).  If a polarity flip of the quadrupole is allowed, even smaller beam envelopes can be achieved.

## Component Inventory

| Description | # required | #available | Peak power specifications per component |
| --- | --- | --- | --- |
|  Quadrupoles
(9 200-MeV quads, 5 Pbar quads to be 
removed from old 8 GeV line during 
shutdown) | 14 | 14 | 50V x 40 A |
| Pulsed Extraction dipoles
(designed, bids are in, contract awaiting 
budget decisions) | 2 | to be built | 500-1000 A (under design) |
| Cooling Ring dipoles
(4 with refurbished coils, to be removed 
from A0 during shutdown) | 5 | >10 | 18V x 711 A |
| Air Core Trim dipoles | 8 |  8 | 24V x 12A |

## Power supplies and power requirements

| Description | # | Power Supply
Requirements | Power (potential peak power)
kW |
| --- | --- | --- | --- |
| 200-MeV. Quadrupoles
Pbar quadrupoles
(many old supplies are available) | 9
5 | 14  (50V x 40A) | 28  |
| Pulsed Extraction dipoles
(power supply to be built in house) | 2 | 300V x 800A
700V x 800A | 0.4 
0.6  |
| Cooling Ring dipole string
(Trans Rex) | 4 | 4 (18V x 711A) | 51  |
| CR dipole, single
(Trans Rex or PEI) | 1 | 18V x 400 A | 7.2  |
| Trims
(need to build bulk supply) | 8 | 8 (24V x 12A) | 2.3  |
| Total Power |  |  | 90 kW |

## Resource Synopsis: M&S

**Beamline Components**
- With the exception of the C magnet, all beamline components are available
- quadrupoles and dipoles
- trim magnets
- diagnostics
- beam stops
- instrumentation and controls such as an eberm system
**Power Supplies**
- With the exception of the pulsed power supply,
- all major supplies and a number of smaller ones are available
- dipole supplies
- misc quad and trim supplies
**Vacuum**
- ion pumps are available (30 liters/min)
- misc vacuum components
**Water**
- 55  Linac water is available
- Tevatron sled available

## Resource requests: Summary

**PPD**
- C magnet
- PPD Machine shop:
- magnet stand fabrication/modify existing stands
- spool pieces
**TD**
- magnet inspection and testing
- small repairs (hoses)
**AD (SWF)**
- C magnet power supply labor
- Installation:
- vacuum, safety, water, power supplies, beamline, controls
**Muon Funds**
- C magnet power supply parts
- electricians
- cable tray and civil (6” bore through shield blocks)

## C magnet specifications:

| General | Value |
| --- | --- |
| Bpeak, range | 6.0 - 6.5 kG |
| Repetition Rate | 15 Hz |
| Pulse Length (half sine wave)  | 8.33 msec |
| Integrated strength, error |  |
| 1st magnet | 0.1668 T-m,  1%  at peak |
| 2nd magnet |  2.5  1st magnet strength, 1%  at peak |
| Good Field Region |  |
| Width, field error | 0.0600 m ( 2.36”), 10-3 at peak |
| Gap | 0.05100 m (2.008”) |
| Beam tube (elliptical) ~width x height | 0.1173 m (4.618”), 0.0508 m (2”) |
| Beam tube thickness | 1.59 10-3 m (0.0625”) |
| 2nd magnet: |  |
| Tube diameter, thickness, outside beamline | 0.08255 m(3.25”), 1.59 10-3 m (0.0625”) |
| Center to center spacing - beam tubes
@upstream magnet entrance | 0.1126 m  0.0003 m (4.433 0.006”) |

## C magnet specificatons cont...

| Physical Dimensions |  |
| --- | --- |
| Minimum spacing between coils (top to bottom) | 0.1080   0.0064 (4.25  0.125”) |
| Maximum slot length |  |
| 1st magnet | 0.4254 m  0.0064 (16.75 0.25”) |
| Maximum steel Length |  |
| 1st magnet | 0.2604 m (10.25”) |
|  |  |
| Required Mechanical Properties |  |
| Operational flexing or fatiguing of coil+core | 0.1 mil |
| Coil or Core temperature rise, at any point | <10 C ,  for  |
| Cooling water available | ~1 gal/min @60psi and 95F |
| Connections, water and power | Standard Fermilab connections |

## 06 Shutdown Tasks - complete

- Quadrupole move
- Installation of new chopper flanges and gate valve
- Further installation can then proceed independent of linac and as time and resources permit

## Chopper Modification Drawings

## New Chopper Parts: detail

## Status of MTA/Linac beamline - summary

- Line design complete and components identified
- Final layouts and full engineering in progress
- C magnet bids contract awarded to Everson; shipping by Jan, 2007
- Q74 move and chopper modifications/gate valve completed ’06 shutdown and A0 CR dipoles pulled from Tevatron enclosure
_**Further installation can now proceed without vacuum interruption/disruption to Linac or Booster**_
- Installation complete in ’07 shutdown