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iitmsat Project Phase B

Team Expansion V Reviews, 13th Sep 4th Oct, 2012

2012 IITM | ISRO

Design of Photomultiplier CalibrationDevice

Lokaditya

AjayrajRakesh

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2012 IITM | ISRO

Problem Statement Definition

PMT is a device that converts light to electricsignals with an amplification factor in the range of

millions. The given PMT (9807B) has a gain of 7

million.

We need to calibrate the PMT to correlate the

output readings to the actual input values.

A LED light is used to calibrate the given PMT. OurTask is to design a cylindrical, light tight support

structure for the PMT and the LED.

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Objectives

The entire casing should be such that it is lighttight.

LED should be inter-changeable conveniently

without having to remove PMT from casing

The cylinder should be insulated from the LED

input voltage

Input to LED given via a Function Generator.

Provision for BNC female port to be included

3

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Methodology

The task handed out to us was fairly simple at theoutset

Task complicated by the words Light proof

Obstacles faced due to practical constraints

Simple and Elegant solution the need of the hour

Too much complication would result in inefficiency

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2012 IITM | ISRO

Construction

Construction of hollow MILD STEEL cylinder of following

dimensions

Inner groove to prevent lid containing LED from sliding further in

5

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Completed Set-up

The Mild Steel Hol lowCylinder

( i ) ( i i )

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Completed Set-up

WoodenBase and

Components

( i )

( i i )

( i i i )

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Completed Set-up

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M i l d S t e e lh o l l o w

C y l i n d e r

W o o d e nB a s e w i t hL E D a n d

L E D h o l d e r

L E Dc o n n e c t o r

w i t h B N Cp o r t

Assembly

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Completed Set-up

9

P M T I n

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Objectives Completed

Hollow cylinder has groove of 10mm depth toprevent wooden base from sliding further in

LED is easily interchangeable with no soldering

required

LED is placed exactly in the centre of the wooden

base as photocathode efficiency is maximum in

centre

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Objectives Completed

Wooden base ensures no leakage of current fromLED to PMT

Entire assembly is stable and can be reassembled

without any hassle

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Thank you!