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January 25, 2005 GRETINA 2004 Review 1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

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Page 1: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 1

GRETINA2004 Annual Review

Steve Virostek

Lawrence Berkeley National Lab

Mechanical System

Page 2: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 2

Presentation Overview

• Mechanical system conceptual design

• Detector mechanical interface

• Installation site interfaces

• Mechanical requirements document

• LN system and target chamber

• Detector scanning table

• Prototype detector QC: CMM and X-ray

Page 3: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 3

Mechanical Conceptual Design

Page 4: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 4

D1

D2

R2

R1

S

Target Ball Radius

• Scientific considerations: the effect on the volume available within the ball and the efficiency of data capture

• Mechanical issues: the quarter sphere detector support radius and the position of the detector mounting flanges

Detector Modules Mounted in 2 Structure around Target Ball at Center

2Structure/Target Ball Size Parameters

Page 5: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 5

GRETINA Assembly Features

Detector module Cap

Preamp housing LN dewar

Quarter sphere shell

Axle bearings

Axle

Worm and worm gear set

HexapodRailroad car, tracks

Flange

Wedge plate (under and attached to detector flange)

Page 6: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 6

Quarter Sphere Structure• Large-radius quarter sphere allows space for

17 detector module flanges as well as sufficient material to provide a stiff structure for accurate positioning

• As the quarter sphere radius increases, the required thickness and weight increase as well – eventually reducing the clearance around GRETINA due to the larger support components

• Preliminary calculations indicate a shell thickness of 3 to 4” with a quarter sphere radius of 25 to 30”

Page 7: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 7

Other Design TopicsAXLE

• Design issues include loaded quarter sphere weight and distances to the bearings

• A larger axle tube size reduces weight but increases the axle bearing cost and impinges on space constraints

• Preliminary calculations indicate an axle tube of 10” OD and 1/2 to 1” thick wall

HEXAPOD

• The hexapod (or Stewart platform) is a fairly standard octahedral mount using ALS struts

• The hexapod is very stiff due to the tensile/compressive (no bending) loading of the struts and is finely adjustable over a large range

• Alignment of a hexapod is non-intuitive, but is easily accomplished using a computer code

WEDGE PLATE

• The absolute error in the shape of the detector caps should be small

• In order to nest the detectors as closely as possible, the position of the caps must be controlled carefully with the flange mount

• Since the distance from the cap to flange is not small nor direct (tolerance stack-up), we will correct for the position of each flange with a custom made wedge plate

• Can accommodate errors of 3 mm in the flange plane, 5 mm out of plane and 1º tilt errors

Page 8: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 8

Detector Mechanical Interface

Module Caps Nest Together with 1mm Nominal Gap

Quad Detector ModuleWedge Plate

2 Structure

+ +

Page 9: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 9

Site Installation Overview

• TBD

Page 10: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 10

ANL Installation

Page 11: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 11

LBNL Installation

The 8x8 needs to move in so that its right end is at the centerline

Page 12: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 12

MSU Installation

Page 13: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 13

ORNL Installation

Page 14: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 14

Requirements Document• Requirements are for the Mechanical System as defined in the PEP:

– Detector Support Structure– Liquid Nitrogen System (interface only)– Target Chamber (interface only)– Detector Installation Tool

• The LN system (ORNL) and the target chamber (Washington U.) design requirements will be presented in separate documents prepared by their respective developers

• Purpose of ME Requirements Document– Based on the Functional Requirements in the PEP

– Describes mechanical requirements necessary to meet Functional Requirements and physics goals

Page 15: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 15

Requirements Document (details)

Coordinate Systems

Tolerances

Page 16: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 16

Requirements Document (details)

2 Spherical Structure

Page 17: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 17

Requirements Document (details)

Structure and Tracks• • • • Translation and Rotation• • • •

Page 18: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 18

Requirements Document (details)

Detector Installation Tool

Material Issues

Page 19: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 19

Requirements Document (details)

Interfaces

• Mechanical …

• Electrical …

• LN System

• Target Chamber

• Transportation

Page 20: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 20

Requirements Document (details)

Interfaces

• Site Specific …

• Operating Envelope …

• Site Requirements …

Page 21: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 21

LN System and Target Chamber

• TBD?

Page 22: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 22

Detector Scanning TableCoincidence scan setup

Scanning table Adjunct cart

The scanning table may be used with or without the adjunct cart.

• Horizontal and vertical americium collimators outline surface areas of crystals

• Vertical cesium collimator…• Vertical cesium collimator in conjunction with slit collimators and cloverleaf detectors…

• Slit collimators with external source….

Page 23: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 23

Scanning TableTriple-crystal prototype detector module

Cloverleaf detectors

XY drive for vertical collimator Elevation drive’s tracking rollers

Vertical source- collimator onXY drive

Horizontal source-collimator on Z drive

Detector module rotary table withdegree markings

Scan cart

Cloverleaf elevation drive

Adjunct cart

Horizontal slits collimator, attached to Z drive

Page 24: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 24

Scanning Table DetailsTriple-crystal prototype detector module

Slit collimator, attached to Z axis

Cloverleaf detectors

Cloverleaf elevation drive

Americium or cesium vertical collimator

Horizontal americium collimator (not visible)on Z drive

Detector module rotary table withdegree markings

XY drive for vertical collimator Elevation drive’s tracking rollers

Page 25: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 25

Detector CMM Measurement

366 points measured at room and liquid-nitrogen temperatures

Results:• Deviation from design value = 0.2 mm (RMS)• Warm – cold difference = 0.02 mm (RMS)

Page 26: January 25, 2005GRETINA 2004 Review1 GRETINA 2004 Annual Review Steve Virostek Lawrence Berkeley National Lab Mechanical System

January 25, 2005 GRETINA 2004 Review 26

Detector X-ray Imaging• Crystal positions were determined by X-ray imaging

at the UC Berkeley Medical Center

The three crystals were positioned withan accuracy of better than 0.5 mm.